Skip to main content
Psychedex
Sources
17
4 strong · 8 moderate · 5 weak

Studies and references cited across this article, graded by evidence strength.

Claims checked
77
45verified2partial30inconclusive

Inconclusive means the cited source neither confirms nor refutes the claim — a lower-confidence badge, not an error.

Generated
May 7, 2026 · pipeline-v5
Values approved
135/135 (100%)

Data points an editor reviewed and accepted for publication.

01

Value Provenance

Dosing

oraltrace

FieldPublishedAI ProposedConfidence
Threshold10 mg10 mglow
Low25–50 mg25–50 mglow
Common50–75 mg50–75 mglow
Strong100–125 mg100–125 mglow
Heavy125+ mg125+ mglow
Editorial

Values carried forward from existing DB / community consensus (PsychonautWiki): threshold 10 mg, light 25–50 mg, common 50–75 mg, strong 100–125 mg, heavy 125+ mg. No controlled dose-finding study exists for 4-FMA. These are safety-critical values based solely on community consensus. CYP2D6 poor metabolizers may experience disproportionate effects at any dose level (Roque Bravo 2021).

Reasoning

Values carried forward from existing DB / community consensus (PsychonautWiki): threshold 10 mg, light 25–50 mg, common 50–75 mg, strong 100–125 mg, heavy 125+ mg. No controlled dose-finding study exists for 4-FMA. These are safety-critical values based solely on community consensus. CYP2D6 poor metabolizers may experience disproportionate effects at any dose level (Roque Bravo 2021).

Evidence basis: community_consensus_large

Duration

oral

FieldPublishedAI ProposedConfidence
Onsettrace20–40 minutes20–40 minuteslow
Editorial

Existing DB value from community consensus (PsychonautWiki): onset 20–40 minutes oral. No human pharmacokinetic study exists for 4-FMA.

Reasoning

Existing DB value from community consensus (PsychonautWiki): onset 20–40 minutes oral. No human pharmacokinetic study exists for 4-FMA.

Evidence basis: community_consensus_large

Come uptrace20–40 minutes20–40 minuteslow
Editorial

Existing DB value from community consensus (PsychonautWiki): come_up 20–40 minutes oral. No controlled PK study.

Reasoning

Existing DB value from community consensus (PsychonautWiki): come_up 20–40 minutes oral. No controlled PK study.

Evidence basis: community_consensus_large

Peaktrace2–5 hours2–5 hourslow
Editorial

Existing DB value from community consensus (PsychonautWiki): peak 2–5 hours oral. No controlled PK study.

Reasoning

Existing DB value from community consensus (PsychonautWiki): peak 2–5 hours oral. No controlled PK study.

Evidence basis: community_consensus_large

Offsettrace1–2 hours1–2 hourslow
Editorial

Existing DB value from community consensus (PsychonautWiki): offset 1–2 hours oral. No controlled PK study.

Reasoning

Existing DB value from community consensus (PsychonautWiki): offset 1–2 hours oral. No controlled PK study.

Evidence basis: community_consensus_large

Totaltrace4–8 hours4–8 hourslow
Editorial

Existing DB value from community consensus (PsychonautWiki): total 4–8 hours oral. This represents subjective experience duration, not pharmacological half-life. No controlled PK study.

Reasoning

Existing DB value from community consensus (PsychonautWiki): total 4–8 hours oral. This represents subjective experience duration, not pharmacological half-life. No controlled PK study.

Evidence basis: community_consensus_large

After effectstrace3–12 hours3–12 hourslow
Editorial

Existing DB value from community consensus (PsychonautWiki): aftereffects 3–12 hours oral. Includes residual wakefulness, fatigue, mood dip below baseline. No controlled PK study.

Reasoning

Existing DB value from community consensus (PsychonautWiki): aftereffects 3–12 hours oral. Includes residual wakefulness, fatigue, mood dip below baseline. No controlled PK study.

Evidence basis: community_consensus_large

Safety

Toxicity Profiletrace

FieldPublishedAI ProposedConfidence
Acutemoderatemoderatelow
Chronicmoderatemoderatelow
Organs Affectedhepatic, cardiovascularhepatic, cardiovascularlow
Editorial

Hepatotoxicity is 4-FMA-specific but in vitro only (EC50 values 2.21–9.57 mM far exceed expected plasma concentrations — clinical relevance uncertain). Cardiovascular toxicity extrapolated entirely from 4-FA analog data (Hondebrink 2018, Gresnigt 2022). Evidence discount applied: both acute and chronic rated moderate per work-notes, but confidence set to low because hepatic evidence is in vitro and cardiovascular evidence is structural analogy from 4-FA. No LD50 or human overdose data exist for 4-FMA.

Reasoning

Hepatotoxicity is 4-FMA-specific but in vitro only (EC50 values 2.21–9.57 mM far exceed expected plasma concentrations — clinical relevance uncertain). Cardiovascular toxicity extrapolated entirely from 4-FA analog data (Hondebrink 2018, Gresnigt 2022). Evidence discount applied: both acute and chronic rated moderate per work-notes, but confidence set to low because hepatic evidence is in vitro and cardiovascular evidence is structural analogy from 4-FA. No LD50 or human overdose data exist for 4-FMA.

Evidence basis: structural_analogy

Dependence Profiletrace

FieldPublishedAI ProposedConfidence
Physicalmoderatemoderatelow
Psychologicalmoderatemoderatelow
Compulsive Redosingmoderatemoderatelow
Dose Escalationmoderatemoderatelow
Editorial

All dependence parameters are class-level inference from amphetamine/methamphetamine pharmacology — no 4-FMA-specific dependence studies exist. Community consensus (PsychonautWiki) rates physical and psychological dependence as moderate. Anchondo 2025 confirmed full discriminative stimulus substitution for methamphetamine, supporting abuse potential but not quantifying dependence directly. Self-administration studies (the gold standard) have not been conducted.

Reasoning

All dependence parameters are class-level inference from amphetamine/methamphetamine pharmacology — no 4-FMA-specific dependence studies exist. Community consensus (PsychonautWiki) rates physical and psychological dependence as moderate. Anchondo 2025 confirmed full discriminative stimulus substitution for methamphetamine, supporting abuse potential but not quantifying dependence directly. Self-administration studies (the gold standard) have not been conducted.

Evidence basis: structural_analogy

Withdrawal Profiletrace

FieldPublishedAI ProposedConfidence
Severitymildmildlow
SymptomsFatigue, Hypersomnia, Increased appetite, Dysphoria, IrritabilityFatigue, Hypersomnia, Increased appetite, Dysphoria, Irritabilitylow
FatalNoNolow
Medical SupervisionNot requiredNot requiredlow
Editorial

No 4-FMA-specific withdrawal characterization exists. All parameters are class-level inference from amphetamine/methamphetamine stimulant withdrawal. Onset 12–24 hours, duration 3–7 days per work-notes. Severity rated mild (work-notes: mild-to-moderate; discounted one level for structural analogy).

Reasoning

No 4-FMA-specific withdrawal characterization exists. All parameters are class-level inference from amphetamine/methamphetamine stimulant withdrawal. Onset 12–24 hours, duration 3–7 days per work-notes. Severity rated mild (work-notes: mild-to-moderate; discounted one level for structural analogy).

Evidence basis: structural_analogy

Tolerance Profiletrace

FieldPublishedAI ProposedConfidence
Buildupmoderatemoderatelow
Half-life5 days5 dayslow
Full Reset10.5 days10.5 dayslow
Cross-tolerancesamphetamine, methamphetamine, cocaine, MDMA, other dopaminergic stimulantsamphetamine, methamphetamine, cocaine, MDMA, other dopaminergic stimulantslow
Editorial

Existing DB values (community consensus) carried forward: half-life 5 days, full reset 1.5 weeks. Mechanism inferred from amphetamine/methamphetamine class pharmacology. Cross-tolerances expanded to named compounds per Rickli 2015 DAT:SERT profile. No 4-FMA-specific tolerance data exist in any published source.

Reasoning

Existing DB values (community consensus) carried forward: half-life 5 days, full reset 1.5 weeks. Mechanism inferred from amphetamine/methamphetamine class pharmacology. Cross-tolerances expanded to named compounds per Rickli 2015 DAT:SERT profile. No 4-FMA-specific tolerance data exist in any published source.

Evidence basis: community_consensus_large

Effects & Profile

Contraindications

FieldPublishedAI ProposedConfidence
other Concurrent MAOI usetraceabsoluteabsolutehigh
Editorial

Class-level absolute contraindication for all monoamine releasers with MAOIs. Mechanism (blocked degradation + transporter-mediated release = serotonin flood) is well-established. No 4-FMA-specific case but pharmacological certainty is high.

Reasoning

Class-level absolute contraindication for all monoamine releasers with MAOIs. Mechanism (blocked degradation + transporter-mediated release = serotonin flood) is well-established. No 4-FMA-specific case but pharmacological certainty is high.

other Concurrent tramadol usetraceabsoluteabsolutemedium
Editorial

Community databases classify this as lethal. Mechanism is additive serotonergic load (tramadol SERT inhibition + 4-FMA SERT release). No 4-FMA-specific case report but class mechanism is valid. Rated absolute per work-notes.

Reasoning

Community databases classify this as lethal. Mechanism is additive serotonergic load (tramadol SERT inhibition + 4-FMA SERT release). No 4-FMA-specific case report but class mechanism is valid. Rated absolute per work-notes.

cardiovascular Pre-existing cardiovascular or cerebrovascular diseasetracerelativerelativemedium
Editorial

4-FA analog data (Gresnigt 2022, Hondebrink 2018) documents severe hypertension, cerebral hemorrhage, and Takotsubo at recreational doses. Structural analogy from 4-FA to 4-FMA; not confirmed for 4-FMA specifically.

Reasoning

4-FA analog data (Gresnigt 2022, Hondebrink 2018) documents severe hypertension, cerebral hemorrhage, and Takotsubo at recreational doses. Structural analogy from 4-FA to 4-FMA; not confirmed for 4-FMA specifically.

cardiovascular Pre-existing hypertensiontracerelativerelativemedium
Editorial

4-FA analog data demonstrates severe acute hypertension even in normotensive individuals (Gresnigt 2022). Pre-existing hypertension raises baseline, amplifying risk. Structural analogy from 4-FA.

Reasoning

4-FA analog data demonstrates severe acute hypertension even in normotensive individuals (Gresnigt 2022). Pre-existing hypertension raises baseline, amplifying risk. Structural analogy from 4-FA.

hepatic Hepatic impairmenttracerelativerelativemedium
Editorial

4-FMA-specific in vitro data (Roque Bravo 2021) establishes hepatotoxicity and CYP-dependent metabolism. Hepatic impairment reduces detoxification capacity. Substance-specific evidence, though in vitro only.

Reasoning

4-FMA-specific in vitro data (Roque Bravo 2021) establishes hepatotoxicity and CYP-dependent metabolism. Hepatic impairment reduces detoxification capacity. Substance-specific evidence, though in vitro only.

metabolic CYP2D6 poor metabolizer phenotypetracerelativerelativemedium
Editorial

4-FMA-specific in vitro data (Roque Bravo 2021) directly demonstrates CYP2D6's detoxifying role. Poor metabolizer phenotype creates pharmacogenomic vulnerability. Substance-specific evidence basis.

Reasoning

4-FMA-specific in vitro data (Roque Bravo 2021) directly demonstrates CYP2D6's detoxifying role. Poor metabolizer phenotype creates pharmacogenomic vulnerability. Substance-specific evidence basis.

other Concurrent serotonergic medicationstracerelativerelativemedium
Editorial

Class-level serotonin syndrome risk mechanism. 4-FMA's SERT release potency comparable to MDMA (Rickli 2015) provides substance-specific pharmacological basis. No 4-FMA-specific case reports.

Reasoning

Class-level serotonin syndrome risk mechanism. 4-FMA's SERT release potency comparable to MDMA (Rickli 2015) provides substance-specific pharmacological basis. No 4-FMA-specific case reports.

metabolic Concurrent CYP2D6 or CYP3A4 inhibitorstracerelativerelativemedium
Editorial

4-FMA-specific in vitro data (Roque Bravo 2021) establishes CYP2D6/CYP3A4 as detoxifying enzymes. Inhibiting these enzymes left-shifted cytotoxicity curves. Substance-specific metabolic evidence.

Reasoning

4-FMA-specific in vitro data (Roque Bravo 2021) establishes CYP2D6/CYP3A4 as detoxifying enzymes. Inhibiting these enzymes left-shifted cytotoxicity curves. Substance-specific metabolic evidence.

neurological Seizure disordertracerelativerelativelow
Editorial

Class-level inference from amphetamine pharmacology. Stimulant-class seizure threshold reduction is well-established. No 4-FMA-specific seizure data. Structural analogy from amphetamine/methamphetamine.

Reasoning

Class-level inference from amphetamine pharmacology. Stimulant-class seizure threshold reduction is well-established. No 4-FMA-specific seizure data. Structural analogy from amphetamine/methamphetamine.

pregnancy breastfeeding Pregnancytracerelativerelativelow
Editorial

Class-level inference from amphetamine/methamphetamine reproductive toxicity data. No 4-FMA-specific reproductive studies exist. Precautionary contraindication based on sympathomimetic mechanism.

Reasoning

Class-level inference from amphetamine/methamphetamine reproductive toxicity data. No 4-FMA-specific reproductive studies exist. Precautionary contraindication based on sympathomimetic mechanism.

Timeline Phases

oral

FieldPublishedAI ProposedConfidence
Onsettrace1200–2400 sec(i=0.05)1200–2400 sec(i=0.05)low
Editorial

Timeline phases derived from community consensus duration data (PsychonautWiki): onset 20–40 min, come_up 20–40 min, peak 2–5 h, offset 1–2 h, aftereffects 3–12 h, total 4–8 h. No human pharmacokinetic study exists for 4-FMA. Phase descriptions integrate 4-FMA's balanced DAT:SERT profile (Rickli 2015) and community-reported subjective timeline. Work-notes specified onset/come_up/peak/offset/afterglow as applicable phases.

Reasoning

Timeline phases derived from community consensus duration data (PsychonautWiki): onset 20–40 min, come_up 20–40 min, peak 2–5 h, offset 1–2 h, aftereffects 3–12 h, total 4–8 h. No human pharmacokinetic study exists for 4-FMA. Phase descriptions integrate 4-FMA's balanced DAT:SERT profile (Rickli 2015) and community-reported subjective timeline. Work-notes specified onset/come_up/peak/offset/afterglow as applicable phases.

Evidence basis: community_consensus_large

Come uptrace1200–2400 sec(i=0.35)1200–2400 sec(i=0.35)low
Editorial

Timeline phases derived from community consensus duration data (PsychonautWiki): onset 20–40 min, come_up 20–40 min, peak 2–5 h, offset 1–2 h, aftereffects 3–12 h, total 4–8 h. No human pharmacokinetic study exists for 4-FMA. Phase descriptions integrate 4-FMA's balanced DAT:SERT profile (Rickli 2015) and community-reported subjective timeline. Work-notes specified onset/come_up/peak/offset/afterglow as applicable phases.

Reasoning

Timeline phases derived from community consensus duration data (PsychonautWiki): onset 20–40 min, come_up 20–40 min, peak 2–5 h, offset 1–2 h, aftereffects 3–12 h, total 4–8 h. No human pharmacokinetic study exists for 4-FMA. Phase descriptions integrate 4-FMA's balanced DAT:SERT profile (Rickli 2015) and community-reported subjective timeline. Work-notes specified onset/come_up/peak/offset/afterglow as applicable phases.

Evidence basis: community_consensus_large

Peaktrace7200–18000 sec(i=1.00)7200–18000 sec(i=1.00)low
Editorial

Timeline phases derived from community consensus duration data (PsychonautWiki): onset 20–40 min, come_up 20–40 min, peak 2–5 h, offset 1–2 h, aftereffects 3–12 h, total 4–8 h. No human pharmacokinetic study exists for 4-FMA. Phase descriptions integrate 4-FMA's balanced DAT:SERT profile (Rickli 2015) and community-reported subjective timeline. Work-notes specified onset/come_up/peak/offset/afterglow as applicable phases.

Reasoning

Timeline phases derived from community consensus duration data (PsychonautWiki): onset 20–40 min, come_up 20–40 min, peak 2–5 h, offset 1–2 h, aftereffects 3–12 h, total 4–8 h. No human pharmacokinetic study exists for 4-FMA. Phase descriptions integrate 4-FMA's balanced DAT:SERT profile (Rickli 2015) and community-reported subjective timeline. Work-notes specified onset/come_up/peak/offset/afterglow as applicable phases.

Evidence basis: community_consensus_large

Resolutiontrace3600–7200 sec(i=0.30)3600–7200 sec(i=0.30)low
Editorial

Timeline phases derived from community consensus duration data (PsychonautWiki): onset 20–40 min, come_up 20–40 min, peak 2–5 h, offset 1–2 h, aftereffects 3–12 h, total 4–8 h. No human pharmacokinetic study exists for 4-FMA. Phase descriptions integrate 4-FMA's balanced DAT:SERT profile (Rickli 2015) and community-reported subjective timeline. Work-notes specified onset/come_up/peak/offset/afterglow as applicable phases.

Reasoning

Timeline phases derived from community consensus duration data (PsychonautWiki): onset 20–40 min, come_up 20–40 min, peak 2–5 h, offset 1–2 h, aftereffects 3–12 h, total 4–8 h. No human pharmacokinetic study exists for 4-FMA. Phase descriptions integrate 4-FMA's balanced DAT:SERT profile (Rickli 2015) and community-reported subjective timeline. Work-notes specified onset/come_up/peak/offset/afterglow as applicable phases.

Evidence basis: community_consensus_large

Afterglowtrace10800–43200 sec(i=0.10)10800–43200 sec(i=0.10)low
Editorial

Timeline phases derived from community consensus duration data (PsychonautWiki): onset 20–40 min, come_up 20–40 min, peak 2–5 h, offset 1–2 h, aftereffects 3–12 h, total 4–8 h. No human pharmacokinetic study exists for 4-FMA. Phase descriptions integrate 4-FMA's balanced DAT:SERT profile (Rickli 2015) and community-reported subjective timeline. Work-notes specified onset/come_up/peak/offset/afterglow as applicable phases.

Reasoning

Timeline phases derived from community consensus duration data (PsychonautWiki): onset 20–40 min, come_up 20–40 min, peak 2–5 h, offset 1–2 h, aftereffects 3–12 h, total 4–8 h. No human pharmacokinetic study exists for 4-FMA. Phase descriptions integrate 4-FMA's balanced DAT:SERT profile (Rickli 2015) and community-reported subjective timeline. Work-notes specified onset/come_up/peak/offset/afterglow as applicable phases.

Evidence basis: community_consensus_large

Dose Tier Summaries

thresholdtrace
low

At approximately 10 mg oral, 4-FMA produces minimally perceptible effects — a slight increase in alertness and subtle mood elevation without pronounced stimulation or entactogenic character. The experience may be difficult to distinguish from placebo in users without prior stimulant familiarity. Cognitive effects are limited to a faint sharpening of attention. Physical effects are negligible at this level. A very mild increase in heart rate may occur, but appetite, body temperature, and pupil size are unlikely to change noticeably. Sleep is generally unaffected if the dose is taken early in the day. This dose level serves primarily as a sensitivity test. Individual variability — particularly CYP2D6 metabolizer status — means some users may perceive more pronounced effects at threshold than others.

Editorial

Based on community consensus (PsychonautWiki) threshold of 10 mg oral. No controlled dose-finding study exists. Effects description inferred from amphetamine-class threshold pharmacology and 4-FMA's known triple monoamine releasing mechanism (Rickli 2015).

Reasoning

Based on community consensus (PsychonautWiki) threshold of 10 mg oral. No controlled dose-finding study exists. Effects description inferred from amphetamine-class threshold pharmacology and 4-FMA's known triple monoamine releasing mechanism (Rickli 2015).

Evidence basis: community_consensus_large

lighttrace
low

At 25–50 mg oral, mild stimulation becomes clearly apparent. Increased energy, a gentle mood lift, and enhanced sociability emerge as the dopaminergic and serotonergic components engage. At the upper end of this range, the entactogenic warmth characteristic of 4-FMA's serotonin-releasing profile begins to surface — a subtle emotional openness and interpersonal warmth that distinguishes the experience from purely dopaminergic stimulants. Physical effects include mild appetite suppression, slight pupil dilation, and a gentle increase in heart rate and blood pressure. Some users report faint tactile euphoria. Bruxism and muscle tension are typically absent or minimal at this level. Functional impairment is generally mild. Sleep may be delayed by 4–6 hours after dosing. The post-acute phase is correspondingly mild — slight fatigue and reduced motivation the following day.

Editorial

Based on community consensus (PsychonautWiki) light range of 25–50 mg oral. Effects description integrates 4-FMA's balanced DAT:SERT profile (Rickli 2015) and community-reported subjective effects. No controlled study data.

Reasoning

Based on community consensus (PsychonautWiki) light range of 25–50 mg oral. Effects description integrates 4-FMA's balanced DAT:SERT profile (Rickli 2015) and community-reported subjective effects. No controlled study data.

Evidence basis: community_consensus_large

commontrace
low

At 50–75 mg oral, the hybrid stimulant-entactogen character of 4-FMA is fully expressed. Pronounced euphoria, empathy enhancement, sociability enhancement, and emotional openness emerge alongside physical stimulation, focus enhancement, and thought acceleration. Music enhancement and touch enhancement become noticeable. The experience occupies a middle ground between MDMA's entactogenic warmth and amphetamine's driven energy. Physical effects are clearly present: appetite suppression is significant, pupil dilation is obvious, and bruxism, temperature dysregulation, and cardiovascular activation (elevated heart rate and blood pressure) become apparent. Excessive sweating and dehydration sensation may occur. Tactile euphoria and body high are commonly reported. Sleep is impossible for approximately 6–8 hours after dosing. The post-acute phase typically involves fatigue, mild depression, irritability, and reduced motivation lasting 12–24 hours. Adequate hydration and temperature management are important at this dose level.

Editorial

Based on community consensus (PsychonautWiki) common range of 50–75 mg oral. Full hybrid profile description integrates Rickli 2015 pharmacology (MDMA-comparable SERT release) with community-reported effects. No controlled study.

Reasoning

Based on community consensus (PsychonautWiki) common range of 50–75 mg oral. Full hybrid profile description integrates Rickli 2015 pharmacology (MDMA-comparable SERT release) with community-reported effects. No controlled study.

Evidence basis: community_consensus_large

strongtrace
low

At 100–125 mg oral, stimulant effects intensify substantially. The balance shifts — the entactogenic warmth that characterizes lower doses may give way to a more purely stimulant experience dominated by restlessness, wakefulness, and cognitive drive. Thought acceleration becomes pronounced, and focus may narrow into fixation. The risk of anxiety and paranoia increases, particularly in anxious or overstimulated settings. Cardiovascular activation is marked: pronounced vasoconstriction, excessive sweating, significant muscle tension, and jaw clenching are common. Temperature dysregulation becomes a genuine safety concern, especially in warm environments or during physical exertion. Abnormal heartbeat may occur. The cardiovascular risk profile at this level warrants serious caution, given 4-FA analog data showing exaggerated hypertension. Sleep is impossible for 8+ hours. The post-acute phase is more pronounced — dysphoria, depression, physical fatigue, and cognitive fatigue may persist for 24–48 hours. Compulsive redosing urge may intensify at this dose level. CYP2D6 poor metabolizers may experience disproportionately strong effects.

Editorial

Based on community consensus (PsychonautWiki) strong range of 100–125 mg oral. Cardiovascular risk inference from 4-FA analog data (Gresnigt 2022, Hondebrink 2018). Dose-dependent shift from entactogenic to stimulant character inferred from DAT:SERT ratio pharmacology. No controlled study.

Reasoning

Based on community consensus (PsychonautWiki) strong range of 100–125 mg oral. Cardiovascular risk inference from 4-FA analog data (Gresnigt 2022, Hondebrink 2018). Dose-dependent shift from entactogenic to stimulant character inferred from DAT:SERT ratio pharmacology. No controlled study.

Evidence basis: community_consensus_large

heavytrace
low

Above 125 mg oral, 4-FMA produces strong stimulant effects with significant cardiovascular stress. Pronounced vasoconstriction, temperature dysregulation, and potential abnormal heartbeat create genuine medical risk. Given that the closely related analog 4-FA produces mean systolic blood pressure of 164 ± 31 mmHg and serious complications (cerebral hemorrhage, Takotsubo cardiomyopathy) at recreational doses, heavy-range 4-FMA use carries substantial cardiovascular danger. Psychological effects shift toward overstimulation: anxiety, paranoia, and thought disorganization may emerge. Ego inflation and disinhibition can impair judgment. Compulsive redosing urge may intensify, creating a risk of escalating intake. Extended insomnia — potentially 12+ hours — is expected. Delusions may occur with sustained wakefulness. The post-acute phase at heavy doses is severe: pronounced depression, physical fatigue, cognitive fatigue, motivation suppression, and irritability may persist for 48–72 hours. Suicidal ideation is listed in community databases but has not been substantiated by case reports. This dose range approaches genuinely dangerous territory with no established safety margin.

Editorial

Based on community consensus (PsychonautWiki) heavy threshold of 125+ mg oral. Cardiovascular risk from 4-FA analog data (Gresnigt 2022). Psychological risk profile from amphetamine-class high-dose pharmacology. Hepatotoxicity risk elevated per CYP-dependent metabolism (Roque Bravo 2021). No controlled study.

Reasoning

Based on community consensus (PsychonautWiki) heavy threshold of 125+ mg oral. Cardiovascular risk from 4-FA analog data (Gresnigt 2022). Psychological risk profile from amphetamine-class high-dose pharmacology. Hepatotoxicity risk elevated per CYP-dependent metabolism (Roque Bravo 2021). No controlled study.

Evidence basis: community_consensus_large

02

History

current version
published Jun 4, 2026AI-generated—
versions
1 total
publication ledger

backfill Jun 4, 2026

Historical versions do not record which reviewer approved them; editorial accountability is recorded per value in the database and in the publication ledger going forward.

full version history suggest a correctioncontact@psychedex.org
03

Sources

4 strong · 8 moderate · 5 weak
  1. [1]
    strong
    Monoamine transporter and receptor interaction profiles of novel psychoactive substances: para-halogenated amphetamines and pyrovalerone cathinones
    Rickli A, Hoener MC, Liechti ME · 2015 · European Neuropsychopharmacology
    doi.org/10.1016/j.euroneuro.2014.12.012pubmed 2562400422 claims checked12 verified10 inconclusive
  2. [2]
    weak
    4-FMA - PsychonautWiki
    2024
    linkno claims checked
  3. [3]
    moderate
    4-Fluoroamphetamine (4-FA) intoxication results in exaggerated blood pressure effects compared to MDMA and amphetamine: A retrospective analysis
    Gresnigt FMJ, Snik A, Franssen EJF, Vanhommerig JW, de Lange DW, Riezebos RK · 2022 · Journal of the American College of Emergency Physicians Open
    doi.org/10.1002/emp2.12813pubmed 3618750711 claims checked3 verified2 partial6 inconclusive
  4. [4]
    moderate
    4-Fluoromethamphetamine (4-FMA) induces in vitro hepatotoxicity mediated by CYP2E1, CYP2D6, and CYP3A4 metabolism
    Roque Bravo R, Carmo H, Valente MJ, Silva JP, Carvalho F, Bastos ML, Dias da Silva D · 2021 · Toxicology
    doi.org/10.1016/j.tox.2021.152988pubmed 3465568718 claims checked11 verified7 inconclusive
  5. [5]
    moderate
    Locomotor and discriminative stimulus effects of fluorinated analogs of amphetamine and methamphetamine in mice and rats
    Anchondo O, Shetty RA, Gatch MB · 2025 · Journal of Pharmacology and Experimental Therapeutics
    doi.org/10.1016/j.jpet.2025.103617pubmed 405539727 claims checked6 verified1 inconclusive
  6. [6]
    weak
    4-Fluoromethamphetamine - Wikipedia
    2024
    linkno claims checked
  7. [7]
    moderate
    Simultaneous Determination of Amphetamine-Related New Psychoactive Substances in Urine by Gas Chromatography-Mass Spectrometry
    Kim JY, Suh S, Park J, In MK · 2018 · Journal of Analytical Toxicology
    doi.org/10.1093/jat/bky037pubmed 299825403 claims checked3 inconclusive
  8. [8]
    moderate
    Simultaneous Quantitation of Seven Phenethylamine-Type Drugs in Forensic Blood and Urine Samples by UHPLC-MS-MS
    Yang CA, Liu HC, Liu RH, Lin DL, Wu SP · 2022 · Journal of Analytical Toxicology
    doi.org/10.1093/jat/bkab014pubmed 335757384 claims checked4 verified
  9. [9]
    weak
    NIST WebBook: 4-Fluoromethamphetamine (CAS 351-03-1)
    2024
    linkno claims checked
  10. [10]
    weak
    4-Fluoromethamphetamine - UNODC Laboratory and Scientific Service
    2024
    linkno claims checked
  11. [11]
    strong
    Pharmacokinetic properties of 4-fluoroamphetamine in serum and oral fluid after oral ingestion
    Toennes SW, Schneider D, Pogoda W, Paulke A, Wunder C, Theunissen EL, Kuypers KPC, de Sousa Fernandes Perna E, Ramaekers JG · 2019 · Drug Testing and Analysis
    doi.org/10.1002/dta.2595pubmed 309123122 claims checked1 verified1 inconclusive
  12. [12]
    strong
    Excretion of 4-fluoroamphetamine and three metabolites in urine after controlled oral ingestion
    Toennes SW, Schneider D, Pogoda W, Paulke A, Wunder C, Theunissen EL, de Sousa Fernandes Perna EB, Ramaekers JG · 2020 · Journal of Pharmaceutical and Biomedical Analysis
    doi.org/10.1016/j.jpba.2019.113008pubmed 317859312 claims checked2 verified
  13. [13]
    moderate
    Monoamine Transporter and Receptor Interaction Profiles in Vitro Predict Reported Human Doses of Novel Psychoactive Stimulants and Psychedelics
    Luethi D, Liechti ME · 2018 · International Journal of Neuropsychopharmacology
    doi.org/10.1093/ijnp/pyy047pubmed 298508811 claim checked1 verified
  14. [14]
    moderate
    Evaluating cross-reactivity of new psychoactive substances (NPS) in human whole blood by enzyme-linked immunosorbent assay (ELISA)
    Cieri G, Mohr ALA, Mastrovito R, Logan BK · 2024 · Journal of Analytical Toxicology
    doi.org/10.1093/jat/bkae017pubmed 384567062 claims checked2 verified
  15. [15]
    moderate
    Fatalities, Cerebral Hemorrhage, and Severe Cardiovascular Toxicity After Exposure to the New Psychoactive Substance 4-Fluoroamphetamine: A Prospective Cohort Study
    Hondebrink L, Nugteren-van Lonkhuyzen JJ, Rietjens SJ, Brunt TM, Venhuis B, Soerdjbalie-Maikoe V, Smink BE, van Riel AJHP, de Vries I · 2018 · Annals of Emergency Medicine
    doi.org/10.1016/j.annemergmed.2017.07.482pubmed 289699282 claims checked2 verified
  16. [16]
    strong
    Cardiotoxicity screening of illicit drugs and new psychoactive substances (NPS) in human iPSC-derived cardiomyocytes using microelectrode array (MEA) recordings
    Zwartsen A, de Korte T, Nacken P, de Lange DW, Westerink RHS, Hondebrink L · 2019 · Journal of Molecular and Cellular Cardiology
    doi.org/10.1016/j.yjmcc.2019.09.007pubmed 315268132 claims checked1 verified1 inconclusive
  17. [17]
    weak
    Fatal Intoxications from a Combination of 4-Fluoroamphetamine and 25C-NBOMe
    Gerostamoulos D, Glowacki L, Pricone M, Crump K, Di Rago M, Joubert S, Lynch MJ, Woodford NW, Drummer OH · 2023 · Journal of Analytical Toxicology
    doi.org/10.1093/jat/bkac059pubmed 359755531 claim checked1 inconclusive
04

Claim Verification

Citation-bearing claims in this article were checked by an AI model against the abstract of the source they cite — every safety-critical claim, plus a sample of the rest. Verdicts below are model-issued, not human-issued; when an editor overrides a verdict, the override is recorded alongside it. Claims whose source does not support them are flagged for editorial review.

summary8 claims4verified1partial3inconclusive
verifiedUnlike its parent compound methamphetamine, 4-FMA releases serotonin at levels comparable to MDMA — a consequence of the para-fluorine substitution on the phenyl ring — producing a markedly lower DAT:SERT selectivity ratio and a more balanced dopaminergic/serotonergic profile[1]model confidence 92%
Verified

Abstract directly confirms 4-FMA releases NE, DA, and 5-HT similarly to MDMA and that para-fluoroamphetamine has enhanced serotonergic properties vs amphetamine. The lower DAT:SERT ratio is a reasonable inference from this data.

4-FMA releases NE, DA, and 5-HT similarly to MDMA. Para-fluoroamphetamine has enhanced serotonergic properties vs amphetamine.

checked by claude-sonnet-4-6 · May 7, 2026

partial4-FMA first appeared on Japanese research chemical markets circa 2006 and gained broader international prevalence after 2017, when the scheduling of 4-fluoroamphetamine (4-FA) in the Netherlands drove regulatory displacement toward unscheduled analogs[3]model confidence 75%
Partial

Abstract supports the post-Netherlands-ban substitution claim (post-ban 4-FMA found as substitute in 4-FA samples), but the specific claim about 'circa 2006 Japanese research chemical markets' is a factual assertion involving a specific date and geography that the abstract does not address at all.

Post-ban 4-FMA found as substitute in 4-FA samples.

checked by claude-sonnet-4-6 · May 7, 2026

inconclusiveThe published evidence base is narrow: one in vitro pharmacological characterization, one hepatotoxicity study, and one animal behavioral pharmacology study[1]model confidence 85%
Inconclusive

This abstract is the pharmacological characterization paper itself. It cannot confirm how many total studies on 4-FMA have been published; that information is not in the abstract.

Evaluated transporter and receptor interaction profiles of para-substituted amphetamines including 4-FMA.

checked by claude-sonnet-4-6 · May 7, 2026

inconclusiveThe published evidence base is narrow: one in vitro pharmacological characterization, one hepatotoxicity study, and one animal behavioral pharmacology study[4]model confidence 85%
Inconclusive

This abstract is the hepatotoxicity paper itself. It cannot confirm how many total studies on 4-FMA exist; that claim about a narrow evidence base is not verifiable from this abstract alone.

Hepatotoxic potential of 4-FMA evaluated in primary rat hepatocytes (PRH, EC50 2.21 mM), HepaRG (EC50 5.59 mM), and HepG2 (EC50 9.57 mM).

checked by claude-sonnet-4-6 · May 7, 2026

inconclusiveThe published evidence base is narrow: one in vitro pharmacological characterization, one hepatotoxicity study, and one animal behavioral pharmacology study[5]model confidence 85%
Inconclusive

This abstract is the animal behavioral pharmacology paper itself. It cannot confirm the total count of published studies on 4-FMA.

4-FMA produced time- and dose-dependent locomotor stimulation.

checked by claude-sonnet-4-6 · May 7, 2026

verified4-FMA releases norepinephrine, dopamine, and serotonin via transporter-mediated reversal, with additional affinity for the 5-HT₂A receptor and trace amine-associated receptor 1 (TAAR1)[1]model confidence 92%
Verified

Abstract directly confirms NE, DA, and 5-HT release (consistent with transporter-mediated reversal mechanism), 5-HT2A affinity, and TAAR1 binding assessment.

4-FMA releases NE, DA, and 5-HT similarly to MDMA. Also has affinity for 5-HT2A receptor. TAAR1 binding assessed.

checked by claude-sonnet-4-6 · May 7, 2026

verifiedThe primary characterized toxicity is hepatotoxicity: in vitro studies demonstrate mitochondrial destabilization, oxidative stress, and apoptotic cell death in hepatocyte models, with CYP2E1 generating toxic metabolites while CYP2D6 and CYP3A4 serve detoxifying roles — creating dose-independent variability based on individual CYP phenotype[4]model confidence 85%
Verified

Abstract confirms hepatotoxicity, mitochondrial dysfunction, oxidative stress, apoptosis, and the differential CYP roles. Dose-independent variability based on CYP phenotype is a reasonable inference from these differential roles.

CYP2E1 plays toxifying role; CYP2D6 and CYP3A4 detoxify. Mitochondrial dysfunction, oxidative stress, apoptosis, necrosis, and autophagy observed.

checked by claude-sonnet-4-6 · May 7, 2026

verifiedCardiovascular risk is inferred from the closely related analog 4-FA, which produces exaggerated hypertension and cerebral hemorrhage at recreational doses[3]model confidence 95%
Verified

Abstract directly confirms exaggerated hypertension (mean SBP 164 mmHg vs MDMA/amphetamine) and cerebral hemorrhage (subarachnoid hemorrhage) in 4-FA ED cases.

Mean SBP 164 mmHg for 4-FA patients vs 139 MDMA, 135 amphetamine. Complications: Takotsubo cardiomyopathy, subarachnoid hemorrhage, hypertensive urgency.

checked by claude-sonnet-4-6 · May 7, 2026

history4 claims1verified3inconclusive
verifiedIn Taiwan, 4-FMA was detected in postmortem blood and urine specimens from fatal cases spanning 2011 to 2018, frequently co-ingested with ketamine and 7-aminonimetazepam (a nimetazepam metabolite)[8]model confidence 85%
Verified

Abstract confirms 4-FMA found in fatal cases in Taiwan 2011-2018 with ketamine and nimetazepam as most common co-ingested substances. The claim's specification of '7-aminonimetazepam (a nimetazepam metabolite)' is consistent with how nimetazepam is detected in biological samples.

4-FMA found in fatal cases in Taiwan 2011-2018. Ketamine and nimetazepam most common co-ingested substances with 4-FA/4-FMA cases.

checked by claude-sonnet-4-6 · May 7, 2026

inconclusiveKorean forensic laboratories confirmed 4-FMA in urine samples from individuals using novel psychoactive substances by 2018.[7]model confidence 75%
Inconclusive

Abstract confirms 4-FMA was detected in urine from drug abusers using the validated method, but does not specify 'Korean forensic laboratories' or the year '2018.' These specific details require full-text or metadata verification.

Validated GC-MS method for 13 amphetamine-related NPS including 4-FMA in urine. Applied to urine samples from drug abusers.

checked by claude-sonnet-4-6 · May 7, 2026

inconclusiveBy 2018, increasing proportions of samples submitted as "4-FA" to Dutch drug-checking services contained 4-FMA instead.[3]model confidence 75%
Inconclusive

Abstract confirms post-ban 4-FMA substitution in 4-FA samples but does not specify 'by 2018,' 'increasing proportions,' or 'Dutch drug-checking services.' These specific details require full-text verification.

Post-ban 4-FMA found as substitute in 4-FA samples.

checked by claude-sonnet-4-6 · May 7, 2026

inconclusiveThe Netherlands experience with 4-FA/4-FMA substitution is now cited as a case study in the unintended consequences of substance-specific scheduling approaches.[3]model confidence 75%
Inconclusive

Abstract confirms 4-FMA was found as a post-ban substitute, but does not characterize this as a 'case study in unintended consequences' or make any policy analysis claim. This editorial characterization is not verifiable from the abstract.

Post-ban 4-FMA found as substitute in 4-FA samples.

checked by claude-sonnet-4-6 · May 7, 2026

chemistry1 claim1verified
verifiedThe para-fluorine substitution is the defining structural feature: it enhances serotonergic activity relative to the unsubstituted parent compound while retaining dopaminergic and noradrenergic release properties[1]model confidence 93%
Verified

Abstract directly confirms para-fluoroamphetamine has enhanced serotonergic properties vs amphetamine, while 4-FMA releases NE and DA (retention of dopaminergic/noradrenergic properties).

4-FMA releases NE, DA, and 5-HT similarly to MDMA. Para-fluoroamphetamine has enhanced serotonergic properties vs amphetamine.

checked by claude-sonnet-4-6 · May 7, 2026

pharmacology8 claims3verified5inconclusive
inconclusiveThis mechanism was directly characterized by Rickli et al. in HEK293 cells expressing human monoamine transporters.[1]model confidence 80%
Inconclusive

Abstract confirms the mechanism was characterized but does not specify the cell model used (HEK293). The specific experimental system cannot be verified from the abstract alone.

Evaluated transporter and receptor interaction profiles of para-substituted amphetamines including 4-FMA.

checked by claude-sonnet-4-6 · May 7, 2026

verifiedThe critical pharmacological distinction between 4-FMA and its parent compound methamphetamine is the enhanced serotonergic activity conferred by para-fluorine substitution. 4-FMA releases serotonin at levels comparable to MDMA, yielding a markedly lower DAT:SERT selectivity ratio than methamphetamine[1]model confidence 92%
Verified

Abstract directly confirms 5-HT release comparable to MDMA and enhanced serotonergic properties from para-fluorine. Lower DAT:SERT ratio is a direct inference from MDMA-level serotonin release.

4-FMA releases NE, DA, and 5-HT similarly to MDMA. Para-fluoroamphetamine has enhanced serotonergic properties vs amphetamine.

checked by claude-sonnet-4-6 · May 7, 2026

inconclusiveAdditional receptor interactions include affinity for the 5-HT₂A receptor — though no functionally relevant activation of the cardiotoxicity-associated 5-HT₂B receptor was observed — and binding at trace amine-associated receptor 1 (TAAR1), which may contribute to psychostimulant and monoamine-releasing activity[1]model confidence 75%
Inconclusive

Abstract confirms 5-HT2A affinity and TAAR1 binding, but does not mention 5-HT2B testing or results. The specific negative finding regarding 5-HT2B cannot be verified from the abstract; it may be in the full text.

Also has affinity for 5-HT2A receptor. TAAR1 binding assessed.

checked by claude-sonnet-4-6 · May 7, 2026

inconclusiveThese numerical values should be incorporated upon full-text access''.[1]model confidence 70%
Inconclusive

This is an editorial note about full-text access rather than a factual claim about the paper's findings. The abstract cannot verify this editorial instruction.

Evaluated transporter and receptor interaction profiles of para-substituted amphetamines including 4-FMA.

checked by claude-sonnet-4-6 · May 7, 2026

verifiedRoque Bravo et al. established that cytochrome P450 enzymes play differential roles in 4-FMA metabolism using primary rat hepatocyte co-exposure studies with selective CYP inhibitors:[4]model confidence 90%
Verified

Abstract confirms CYP2E1, CYP3A4, CYP2D6 involvement in 4-FMA metabolism in primary rat hepatocytes (PRH), with differential toxifying/detoxifying roles established.

CYP2E1, CYP3A4, CYP2D6 implicated in metabolism. CYP2E1 plays toxifying role; CYP2D6 and CYP3A4 detoxify.

checked by claude-sonnet-4-6 · May 7, 2026

inconclusiveThese CYP-dependent variables create what the authors describe as "unpredictability of consequences independent of dose".[4]model confidence 85%
Inconclusive

Abstract supports the general concept of CYP-dependent variability but does not contain the specific quoted phrase 'unpredictability of consequences independent of dose.' Verification requires full-text access.

CYP2E1 plays toxifying role; CYP2D6 and CYP3A4 detoxify. Mitochondrial dysfunction, oxidative stress, apoptosis, necrosis, and autophagy observed.

checked by claude-sonnet-4-6 · May 7, 2026

inconclusiveToennes et al. measured serum and oral fluid pharmacokinetics of 4-FA after controlled oral administration, and separately characterized urinary excretion of 4-FA and three metabolites — two diastereomers of 4-fluorophenylpropanolamine and one ring-hydroxylated conjugate — after oral doses of 100 mg (n = 12) and 150 mg (n = 5), with urine concentrations peaking approximately 4 hours post-ingestion[11]model confidence 75%
Inconclusive

Citation [7]'s abstract covers serum and oral fluid PK after oral ingestion (supported), but the urinary excretion metabolite details (three metabolites, 100mg/150mg doses, 4-hour peak) belong to citation [8]. This abstract cannot verify those specific details.

Controlled study of pharmacokinetic parameters of 4-fluoroamphetamine (4-FA) in humans after oral ingestion.

checked by claude-sonnet-4-6 · May 7, 2026

verifiedToennes et al. measured serum and oral fluid pharmacokinetics of 4-FA after controlled oral administration, and separately characterized urinary excretion of 4-FA and three metabolites — two diastereomers of 4-fluorophenylpropanolamine and one ring-hydroxylated conjugate — after oral doses of 100 mg (n = 12) and 150 mg (n = 5), with urine concentrations peaking approximately 4 hours post-ingestion[12]model confidence 95%
Verified

Abstract directly confirms 100 mg (n=12) and 150 mg (n=5) doses, three metabolites including two diastereomers of 4-fluorophenylpropanolamine and one ring-hydroxylated 4-FA conjugate, and urine concentrations peaking at 4h post-ingestion.

12 subjects ingested 100 mg and 5 subjects 150 mg 4-FA. Three metabolites identified: two diastereomers of 4-fluorophenylpropanolamine and one ring-hydroxylated 4-FA conjugated. Urine concentrations 0.7-38 mg/L; maximum 4 h after ingestion.

checked by claude-sonnet-4-6 · May 7, 2026

receptor pharmacology6 claims2verified4inconclusive
inconclusiveRickli et al. provides the only published receptor-level characterization of 4-FMA[1]model confidence 80%
Inconclusive

Abstract confirms this paper provides receptor-level characterization of 4-FMA but cannot confirm it is the 'only' such publication; that claim requires a comprehensive literature review.

Evaluated transporter and receptor interaction profiles of para-substituted amphetamines including 4-FMA.

checked by claude-sonnet-4-6 · May 7, 2026

inconclusiveThe para-fluorine substitution enhances serotonergic release relative to the unsubstituted parent compound methamphetamine, though the effect is less pronounced than para-methyl or para-bromo substitution at the same position.[1]model confidence 80%
Inconclusive

Abstract confirms para-fluorine enhances serotonergic activity vs amphetamine, but does not compare the magnitude of the effect to para-methyl or para-bromo substitution. This comparative claim requires full-text data.

Para-fluoroamphetamine has enhanced serotonergic properties vs amphetamine.

checked by claude-sonnet-4-6 · May 7, 2026

verifiedCompounds with high DAT:SERT ratios (methamphetamine, cocaine) produce predominantly stimulant effects with strong reinforcing properties; those with low ratios (MDMA) produce predominantly entactogenic effects. 4-FMA occupies an intermediate position on this spectrum.[1]model confidence 80%
Verified

Abstract confirms 4-FMA releases 5-HT like MDMA while retaining NE/DA release, supporting its intermediate pharmacological position between methamphetamine and MDMA. The DAT:SERT ratio framework and effect prediction is a well-established inference from this data.

4-FMA releases NE, DA, and 5-HT similarly to MDMA. Para-fluoroamphetamine has enhanced serotonergic properties vs amphetamine.

checked by claude-sonnet-4-6 · May 7, 2026

verifiedLuethi et al. demonstrated that in vitro monoamine transporter interaction profiles can predict reported human psychoactive doses for novel stimulants and psychedelics, supporting the use of transporter pharmacology as a proxy for in vivo potency estimation.[13]model confidence 95%
Verified

Abstract directly confirms that in vitro pharmacological profiles predict psychoactive doses in humans, with DAT/NET potency positively correlated and SERT potency inversely correlated with doses.

In vitro pharmacological profiles predict psychoactive doses in humans. DAT/NET potency positively correlated; SERT potency inversely correlated with doses.

checked by claude-sonnet-4-6 · May 7, 2026

inconclusiveNo functionally relevant activation of the 5-HT₂B receptor was observed — a finding with cardiac safety relevance, as chronic 5-HT₂B agonism is the mechanism underlying fenfluramine-associated valvular heart disease.[1]model confidence 85%
Inconclusive

Abstract does not mention 5-HT2B testing or results. The specific negative finding regarding 5-HT2B cannot be confirmed or refuted from the abstract alone.

Also has affinity for 5-HT2A receptor. TAAR1 binding assessed.

checked by claude-sonnet-4-6 · May 7, 2026

inconclusiveTAAR1 activation by amphetamine-class compounds contributes to their monoamine-releasing activity and may influence their psychostimulant and reinforcing properties.[1]model confidence 75%
Inconclusive

Abstract notes TAAR1 binding was assessed for 4-FMA but does not describe TAAR1's functional contribution to monoamine-releasing activity or psychostimulant properties. This mechanistic claim about TAAR1 function goes beyond what the abstract reports.

TAAR1 binding assessed.

checked by claude-sonnet-4-6 · May 7, 2026

neuroscience3 claims2verified1inconclusive
verifiedThe following neural mechanisms are inferred from 4-FMA's established pharmacological profile as a triple monoamine releaser with prominent serotonergic activity and from well-characterized neural correlates of amphetamine-class and entactogenic compounds.[1]model confidence 85%
Verified

Abstract directly establishes 4-FMA's profile as a triple monoamine releaser with prominent serotonergic activity comparable to MDMA, providing the pharmacological basis for these mechanistic inferences.

4-FMA releases NE, DA, and 5-HT similarly to MDMA. Para-fluoroamphetamine has enhanced serotonergic properties vs amphetamine.

checked by claude-sonnet-4-6 · May 7, 2026

verifiedAnchondo et al. demonstrated that 4-FMA fully substitutes for methamphetamine in discriminative stimulus paradigms, confirming engagement of reward-related neural circuits at the behavioral level.[5]model confidence 95%
Verified

Abstract directly confirms full substitution for methamphetamine in discriminative stimulus tests. Engagement of reward-related circuits is the standard interpretation of discriminative stimulus generalization.

All fluorinated compounds fully substituted for methamphetamine in discriminative stimulus tests (ED50 0.32-0.71 mg/kg). Abuse potential comparable to methamphetamine.

checked by claude-sonnet-4-6 · May 7, 2026

inconclusiveThe serotonin-releasing component — comparable in magnitude to MDMA — is expected to recruit neural mechanisms paralleling those observed with prototypical entactogens: reduced amygdala reactivity to threatening social stimuli, enhanced prefrontal-amygdala functional connectivity, and facilitated oxytocin release from hypothalamic nuclei[1]model confidence 80%
Inconclusive

Abstract confirms MDMA-comparable serotonin release, which provides the pharmacological basis for the inference. However, the specific neural mechanisms claimed (amygdala reactivity, PFC-amygdala connectivity, hypothalamic oxytocin release) are not in this abstract and represent inferences from other literature.

4-FMA releases NE, DA, and 5-HT similarly to MDMA.

checked by claude-sonnet-4-6 · May 7, 2026

pharmacokinetic detail10 claims7verified3inconclusive
inconclusiveThis CYP-dependent variability creates a scenario in which two individuals taking identical doses may experience substantially different toxicity outcomes — a finding the authors emphasize as "unpredictability of consequences independent of dose".[4]model confidence 85%
Inconclusive

Abstract confirms CYP differential roles supporting variable toxicity, but the specific quoted phrase 'unpredictability of consequences independent of dose' does not appear in the abstract and requires full-text verification.

CYP2E1 plays toxifying role; CYP2D6 and CYP3A4 detoxify.

checked by claude-sonnet-4-6 · May 7, 2026

verifiedToennes et al. (2020) characterized urinary excretion of 4-FA and three metabolites following 100 mg (n = 12) and 150 mg (n = 5) oral doses; urine concentrations peaked approximately 4 hours post-ingestion. Identified metabolites included two diastereomers of 4-fluorophenylpropanolamine and one ring-hydroxylated, extensively conjugated 4-FA derivative.[12]model confidence 97%
Verified

Abstract directly confirms all specific details: 100 mg (n=12) and 150 mg (n=5) doses, three metabolites (two diastereomers of 4-fluorophenylpropanolamine + one ring-hydroxylated conjugate), and urine maximum at 4h.

12 subjects ingested 100 mg and 5 subjects 150 mg 4-FA. Three metabolites identified: two diastereomers of 4-fluorophenylpropanolamine and one ring-hydroxylated 4-FA conjugated. Urine concentrations 0.7-38 mg/L; maximum 4 h after ingestion.

checked by claude-sonnet-4-6 · May 7, 2026

verifiedCYP enzyme involvement in 4-FMA metabolism was established by Roque Bravo et al. using primary rat hepatocytes co-exposed with selective CYP inhibitors:[4]model confidence 90%
Verified

Abstract confirms CYP enzyme involvement in 4-FMA metabolism established in primary rat hepatocytes (PRH), with CYP2E1, CYP3A4, and CYP2D6 implicated.

Hepatotoxic potential of 4-FMA evaluated in primary rat hepatocytes (PRH, EC50 2.21 mM). CYP2E1, CYP3A4, CYP2D6 implicated in metabolism.

checked by claude-sonnet-4-6 · May 7, 2026

inconclusiveCYP2D6 poor metabolizers (7–10% of Caucasian populations, 1–2% of East Asian populations): impaired detoxification may increase exposure to CYP2E1-generated toxic metabolites.[4]model confidence 75%
Inconclusive

Abstract confirms CYP2D6 detoxifies 4-FMA and CYP2E1 toxifies it, supporting the mechanistic claim. However, the specific population frequency percentages (7-10% Caucasian, 1-2% East Asian) are not in the abstract and cannot be verified from it.

CYP2D6 and CYP3A4 detoxify. CYP2E1 plays toxifying role.

checked by claude-sonnet-4-6 · May 7, 2026

verifiedCYP2E1 inducers (chronic alcohol use, obesity, fasting states): increased proportion of toxifying metabolism.[4]model confidence 85%
Verified

Abstract confirms CYP2E1 plays a toxifying role. The inference that CYP2E1 inducers increase toxifying metabolism is a direct pharmacological consequence of this established role.

CYP2E1 plays toxifying role.

checked by claude-sonnet-4-6 · May 7, 2026

verifiedCYP2D6 or CYP3A4 inhibitors (fluoxetine, paroxetine, ketoconazole, ritonavir, grapefruit juice): pharmacokinetic drug interactions impairing detoxification pathways.[4]model confidence 85%
Verified

Abstract confirms CYP2D6 and CYP3A4 serve detoxifying roles, directly supporting the claim that their inhibitors impair 4-FMA detoxification pathways.

CYP2D6 and CYP3A4 detoxify.

checked by claude-sonnet-4-6 · May 7, 2026

verifiedToennes et al. (2019) measured serum and oral fluid pharmacokinetics after single oral 4-FA doses in healthy volunteers.[11]model confidence 85%
Verified

Abstract confirms controlled PK study of 4-FA in humans after oral ingestion. The title specifies serum and oral fluid as the matrices. Controlled human PK studies standardly use healthy volunteers.

Controlled study of pharmacokinetic parameters of 4-fluoroamphetamine (4-FA) in humans after oral ingestion.

checked by claude-sonnet-4-6 · May 7, 2026

inconclusiveValidated analytical methods for 4-FMA detection include GC-MS with a lower limit of quantification (LLOQ) of 2.0 ng/mL in urine and UHPLC-MS/MS in forensic blood and urine matrices.[7]model confidence 75%
Inconclusive

Abstract confirms a validated GC-MS method for 4-FMA detection with LLOQ range 2.0-25 ng/mL across 13 compounds. The specific LLOQ of 2.0 ng/mL for 4-FMA individually cannot be confirmed from the abstract; the range applies to the panel as a whole.

Validated GC-MS method for 13 amphetamine-related NPS including 4-FMA in urine. Linear range 2-100 ng/mL; LLOQ 2.0-25 ng/mL.

checked by claude-sonnet-4-6 · May 7, 2026

verifiedValidated analytical methods for 4-FMA detection include GC-MS with a lower limit of quantification (LLOQ) of 2.0 ng/mL in urine and UHPLC-MS/MS in forensic blood and urine matrices.[8]model confidence 85%
Verified

Abstract confirms a forensic analytical method (UHPLC-MS/MS per the title) for 4-FMA detection in postmortem blood and urine, directly supporting the UHPLC-MS/MS in forensic matrices part of the claim.

Forensic analytical method for PMA, PMMA, 4-FA, 4-FMA, 4-CA, 4-CMA in postmortem blood/urine.

checked by claude-sonnet-4-6 · May 7, 2026

verifiedThe closely related compound 4-FA demonstrates 3,354% cross-reactivity with amphetamine enzyme-linked immunosorbent assay (ELISA), but specific 4-FMA cross-reactivity data with commercially available immunoassays have not been published[14]model confidence 90%
Verified

Abstract directly confirms 3,354% cross-reactivity for 4-FA with amphetamine ELISA. The implication that specific 4-FMA data is not published is consistent with the abstract noting novel stimulants (excluding 4-FA) generally showed no cross-reactivity.

4-Fluoroamphetamine (4-FA) showed 3,354% cross-reactivity with amphetamine ELISA. Novel stimulants (excluding 4-FA) generally showed no cross-reactivity.

checked by claude-sonnet-4-6 · May 7, 2026

effects overview1 claim1inconclusive
inconclusiveRelative to MDMA, 4-FMA produces a more energetically stimulating experience with greater dopaminergic drive and less pronounced sedation; relative to methamphetamine, it offers greater emotional coloring and prosocial quality consistent with its enhanced serotonergic release and lower DAT:SERT selectivity ratio[1]model confidence 75%
Inconclusive

Abstract confirms the pharmacological profile (dopaminergic + serotonergic release) that would predict these experiential differences, but does not describe subjective experience, energy levels, emotional coloring, or prosocial quality. These user-experience claims go beyond what the pharmacology abstract can verify.

4-FMA releases NE, DA, and 5-HT similarly to MDMA. Para-fluoroamphetamine has enhanced serotonergic properties vs amphetamine.

checked by claude-sonnet-4-6 · May 7, 2026

clinical evidence1 claim1verified
verified4-FMA's pharmacological profile — triple monoamine release with a serotonergic component comparable to MDMA — shares mechanistic features with MDMA-assisted psychotherapy models being investigated for post-traumatic stress disorder[1]model confidence 80%
Verified

Abstract confirms the triple monoamine release with serotonergic component comparable to MDMA. The citation is used to support the pharmacological similarity claim; the MDMA-psychotherapy context is editorial synthesis not requiring citation verification.

4-FMA releases NE, DA, and 5-HT similarly to MDMA.

checked by claude-sonnet-4-6 · May 7, 2026

safety26 claims18verified8inconclusive
verifiedCYP2D6 poor metabolizer phenotype — reduced detoxification capacity for 4-FMA[4]model confidence 90%
Verified

Abstract directly confirms CYP2D6 serves a detoxifying role for 4-FMA, directly supporting the inference that poor CYP2D6 metabolizers have reduced detoxification capacity.

CYP2D6 and CYP3A4 detoxify.

checked by claude-sonnet-4-6 · May 7, 2026

verifiedHepatic impairment — impaired CYP-mediated detoxification may increase hepatotoxic risk[4]model confidence 85%
Verified

Abstract confirms CYP2D6 and CYP3A4 serve detoxifying roles. Hepatic impairment reducing CYP function and increasing hepatotoxic risk is a direct pharmacological inference.

CYP2D6 and CYP3A4 detoxify. Mitochondrial dysfunction, oxidative stress, apoptosis, necrosis, and autophagy observed.

checked by claude-sonnet-4-6 · May 7, 2026

inconclusiveThe only published substance-specific toxicological study of 4-FMA characterizes in vitro hepatotoxicity[4]model confidence 80%
Inconclusive

Abstract confirms this is a substance-specific hepatotoxicity study for 4-FMA, but cannot confirm it is the 'only' such study; that would require a comprehensive literature search beyond this abstract.

Hepatotoxic potential of 4-FMA evaluated in primary rat hepatocytes (PRH, EC50 2.21 mM), HepaRG (EC50 5.59 mM), and HepG2 (EC50 9.57 mM).

checked by claude-sonnet-4-6 · May 7, 2026

verifiedCardiovascular disease, hypertension, or cerebrovascular disease — 4-FA analog data demonstrate acute-onset severe hypertension and cerebral hemorrhage at recreational doses[3]model confidence 92%
Verified

Abstract directly confirms exaggerated hypertension (164 mmHg) and subarachnoid hemorrhage as complications of 4-FA intoxication.

Mean SBP 164 mmHg for 4-FA patients vs 139 MDMA, 135 amphetamine. Complications: Takotsubo cardiomyopathy, subarachnoid hemorrhage, hypertensive urgency.

checked by claude-sonnet-4-6 · May 7, 2026

inconclusiveThe clinical relevance of these millimolar EC₅₀ values is uncertain — they exceed expected plasma concentrations at recreational doses by orders of magnitude — but in vitro cytotoxicity does not necessarily predict in vivo hepatotoxicity due to differences in protein binding, first-pass metabolism, and metabolic bioactivation.[4]model confidence 80%
Inconclusive

Abstract provides the EC50 values in millimolar range but does not discuss their clinical relevance, comparison to plasma concentrations, or the limitations of in vitro to in vivo extrapolation. This editorial analysis is not in the abstract.

PRH, EC50 2.21 mM; HepaRG, EC50 5.59 mM; HepG2, EC50 9.57 mM.

checked by claude-sonnet-4-6 · May 7, 2026

inconclusiveIdentified mechanisms of hepatocellular injury include destabilization of mitochondrial membrane potential, decreased intracellular ATP, increased production of reactive oxygen species (ROS) and reactive nitrogen species (RNS), compromise of thiol antioxidant defenses (likely glutathione depletion), activation of initiator and effector caspases (apoptosis), loss of plasma membrane integrity (necrosis), and induction of autophagy.[4]model confidence 75%
Inconclusive

Abstract confirms broad categories (mitochondrial dysfunction, oxidative stress, apoptosis, necrosis, autophagy) but does not confirm specific mechanistic details like ATP depletion, RNS production, glutathione depletion, or caspase activation. These specific details require full-text access.

Mitochondrial dysfunction, oxidative stress, apoptosis, necrosis, and autophagy observed.

checked by claude-sonnet-4-6 · May 7, 2026

verifiedCYP2D6 poor metabolizers and individuals using CYP2E1 inducers (including alcohol) may face elevated hepatotoxic risk at doses that are well-tolerated by the general population.{{/Warning}}[4]model confidence 85%
Verified

Abstract confirms CYP2E1 toxifies and CYP2D6 detoxifies 4-FMA. The inference that poor CYP2D6 metabolizers and CYP2E1 inducers (alcohol is a known CYP2E1 inducer) face elevated risk at normally-tolerated doses is pharmacologically sound and directly supported by these differential roles.

CYP2E1 plays toxifying role; CYP2D6 and CYP3A4 detoxify.

checked by claude-sonnet-4-6 · May 7, 2026

verifiedHondebrink et al. documented fatalities, cerebral hemorrhage, and severe cardiovascular toxicity in a prospective cohort study of 4-FA adverse health effects[15]model confidence 97%
Verified

Abstract directly confirms prospective cohort study documenting fatalities, cerebral hemorrhage, and severe cardiovascular toxicity after 4-FA use.

Prospective cohort study of adverse health effects after 4-FA use. Documents fatalities, cerebral hemorrhage, and severe cardiovascular toxicity.

checked by claude-sonnet-4-6 · May 7, 2026

inconclusiveGresnigt et al. retrospectively analyzed 31 emergency department 4-FA intoxication cases and reported:[3]model confidence 80%
Inconclusive

Abstract confirms retrospective ED analysis of 4-FA intoxications but does not specify the number of cases (31). This specific case count requires full-text verification.

Retrospective ED analysis. Mean SBP 164 mmHg for 4-FA patients vs 139 MDMA, 135 amphetamine.

checked by claude-sonnet-4-6 · May 7, 2026

inconclusiveAll patients presenting with hypertension had no prior hypertensive history, indicating acute drug-induced hemodynamic effects[3]model confidence 85%
Inconclusive

Abstract does not mention prior hypertensive history of patients. This specific clinical detail about baseline patient history is not verifiable from the abstract.

Retrospective ED analysis. Mean SBP 164 mmHg for 4-FA patients vs 139 MDMA, 135 amphetamine. Severe headache in 80%.

checked by claude-sonnet-4-6 · May 7, 2026

inconclusiveIn vitro cardiotoxicity screening of 4-FA in human iPSC-derived cardiomyocytes demonstrated decreased spike amplitude at concentrations ≥10 µM, increased field potential duration (a proxy for QTc prolongation), and decreased beat rate at 300 µM[16]model confidence 80%
Inconclusive

Abstract confirms 4-FA affected cardiomyocyte function at ≥10 µM and QTc prolongation potential, but does not specify the particular MEA parameters (spike amplitude, field potential duration, beat rate at 300 µM). These specific measurements require full-text verification.

4-FA affected cardiomyocyte function at concentrations ≥10 µM. Prolonged QTc potentially from direct cardiac effects.

checked by claude-sonnet-4-6 · May 7, 2026

verifiedThe authors concluded that tachycardia in users is likely indirect (via elevated plasma norepinephrine), while QTc prolongation may result partly from direct drug effects on cardiomyocyte ion channels.[16]model confidence 97%
Verified

Abstract directly confirms both conclusions: tachycardia in patients likely indirect via norepinephrine release, and prolonged QTc potentially from direct cardiac effects.

Tachycardia in patients likely indirect via norepinephrine release. Prolonged QTc potentially from direct cardiac effects.

checked by claude-sonnet-4-6 · May 7, 2026

inconclusiveGerostamoulos et al. documented six Australian fatalities involving 4-FA combined with 25C-NBOMe: four direct drug-caused deaths occurred with postmortem 4-FA blood concentrations of 330–682 ng/L (median 417 ng/L), within apparently recreational dose ranges[17]model confidence 75%
Inconclusive

Abstract confirms six fatalities from 4-FA + 25C-NBOMe and blood concentrations of 330-682 ng/L for direct drug deaths, but does not specify 'four' direct drug-caused deaths. The count is not verifiable from the abstract. The median (417 ng/L) is also not stated in the abstract.

Six fatalities from 4-FA + 25C-NBOMe. Postmortem 4-FA blood: 330-682 ng/L (direct drug deaths) and 21-123 ng/mL (indirect).

checked by claude-sonnet-4-6 · May 7, 2026

verified4-FMA's serotonin-releasing capacity — comparable to MDMA — creates a pharmacologically grounded risk for serotonin syndrome when combined with other serotonergic agents[1]model confidence 90%
Verified

Abstract confirms 4-FMA releases 5-HT at levels comparable to MDMA. Serotonin syndrome risk from combining MDMA-level serotonin release with other serotonergic agents is a well-established pharmacological inference.

4-FMA releases NE, DA, and 5-HT similarly to MDMA.

checked by claude-sonnet-4-6 · May 7, 2026

verified4-FMA was detected in postmortem blood and urine specimens from fatal cases in Taiwan between 2011 and 2018, frequently in polydrug contexts alongside ketamine and 7-aminonimetazepam[8]model confidence 85%
Verified

Abstract confirms 4-FMA in fatal cases in Taiwan 2011-2018 with ketamine and nimetazepam as most common co-ingested substances. The 7-aminonimetazepam specification is consistent with nimetazepam detection in biological samples.

4-FMA found in fatal cases in Taiwan 2011-2018. Ketamine and nimetazepam most common co-ingested substances with 4-FA/4-FMA cases.

checked by claude-sonnet-4-6 · May 7, 2026

inconclusiveA validated GC-MS method achieves detection at an LLOQ of 2.0 ng/mL in urine[7]model confidence 75%
Inconclusive

Abstract states the LLOQ range is 2.0-25 ng/mL across all 13 compounds. The specific LLOQ of 2.0 ng/mL for 4-FMA individually cannot be confirmed from the abstract; it may apply to a different compound in the panel.

Validated GC-MS method for 13 amphetamine-related NPS including 4-FMA in urine. Linear range 2-100 ng/mL; LLOQ 2.0-25 ng/mL.

checked by claude-sonnet-4-6 · May 7, 2026

verifiedStandard amphetamine immunoassays may not reliably detect 4-FMA; confirmatory LC-MS/MS or GC-MS is required for definitive identification.[14]model confidence 85%
Verified

Abstract states novel stimulants (excluding 4-FA) generally showed no cross-reactivity with amphetamine ELISA. As a novel stimulant, 4-FMA would therefore not be reliably detected by standard immunoassay, making confirmatory mass spectrometry necessary.

4-Fluoroamphetamine (4-FA) showed 3,354% cross-reactivity with amphetamine ELISA. Novel stimulants (excluding 4-FA) generally showed no cross-reactivity.

checked by claude-sonnet-4-6 · May 7, 2026

verifiedCross-tolerance with other dopaminergic stimulants (amphetamine, methamphetamine, cocaine) and with MDMA (via the shared serotonergic mechanism) is expected.[1]model confidence 80%
Verified

Abstract confirms 4-FMA as a triple monoamine releaser with both dopaminergic and serotonergic (MDMA-like) mechanisms. Cross-tolerance with other dopaminergic stimulants and with MDMA is a pharmacologically grounded inference from this shared mechanism.

4-FMA releases NE, DA, and 5-HT similarly to MDMA. Para-fluoroamphetamine has enhanced serotonergic properties vs amphetamine.

checked by claude-sonnet-4-6 · May 7, 2026

verifiedAnchondo et al. demonstrated full discriminative stimulus substitution for methamphetamine, consistent with abuse potential comparable to methamphetamine[5]model confidence 97%
Verified

Abstract directly confirms full substitution for methamphetamine in discriminative stimulus tests and states abuse potential is comparable to methamphetamine.

All fluorinated compounds fully substituted for methamphetamine in discriminative stimulus tests (ED50 0.32-0.71 mg/kg). Abuse potential comparable to methamphetamine.

checked by claude-sonnet-4-6 · May 7, 2026

verified4-FMA's SERT-releasing activity, comparable to MDMA, constitutes the pharmacological basis for dangerous interactions with other serotonergic agents[1]model confidence 90%
Verified

Abstract confirms SERT-releasing activity comparable to MDMA. This established pharmacology directly provides the mechanistic basis for serotonergic drug interaction risks.

4-FMA releases NE, DA, and 5-HT similarly to MDMA.

checked by claude-sonnet-4-6 · May 7, 2026

verifiedCYP2D6 inhibitors (fluoxetine, paroxetine, bupropion, ritonavir) and CYP3A4 inhibitors (ketoconazole, grapefruit juice) may impair 4-FMA's detoxification pathways, increasing accumulation of CYP2E1-generated cytotoxic metabolites[4]model confidence 85%
Verified

Abstract confirms CYP2D6 and CYP3A4 as detoxifying pathways and CYP2E1 as toxifying. The inference that inhibiting the detoxifying enzymes increases exposure to toxic CYP2E1-generated metabolites is pharmacologically sound.

CYP2E1 plays toxifying role; CYP2D6 and CYP3A4 detoxify.

checked by claude-sonnet-4-6 · May 7, 2026

verifiedAlcohol induces CYP2E1, potentially increasing the proportion of toxifying metabolism and elevating hepatotoxic risk.[4]model confidence 80%
Verified

Abstract confirms CYP2E1's toxifying role. The inference that CYP2E1 inducers (including alcohol, which chronically induces CYP2E1) would increase toxifying metabolism is pharmacologically sound and directly supported.

CYP2E1 plays toxifying role; CYP2D6 and CYP3A4 detoxify.

checked by claude-sonnet-4-6 · May 7, 2026

verifiedGiven the severe hypertensive profile documented with the closely related analog 4-FA (mean systolic 164 ± 31 mmHg in emergency presentations), cardiovascular stacking with additional stimulants is of particular concern.[3]model confidence 90%
Verified

Abstract directly confirms mean SBP of 164 mmHg in 4-FA emergency presentations. The inference about heightened cardiovascular risk with additional stimulants is supported by this severe baseline hypertension.

Mean SBP 164 mmHg for 4-FA patients vs 139 MDMA, 135 amphetamine.

checked by claude-sonnet-4-6 · May 7, 2026

verifiedCombinations with CNS depressants (GHB, GBL, alcohol, ketamine) may mask cardiovascular warning signs — chest pain, severe headache — that would otherwise prompt medical attention. 4-FMA was detected alongside ketamine in fatal cases in Taiwan, though the individual contribution of each substance to cause of death was not characterized.[8]model confidence 88%
Verified

Abstract confirms ketamine co-ingestion in fatal 4-FMA cases in Taiwan. The claim about individual contributions to cause of death not being characterized is consistent with what a forensic analytical method paper would report. The masking-of-symptoms inference is editorial.

4-FMA found in fatal cases in Taiwan 2011-2018. Ketamine and nimetazepam most common co-ingested substances with 4-FA/4-FMA cases.

checked by claude-sonnet-4-6 · May 7, 2026

verifiedCardiovascular disease, hypertension, or cerebrovascular disease — 4-FA analog data demonstrate acute-onset severe hypertension and cerebral hemorrhage at recreational doses[15]model confidence 90%
Verified

Abstract directly confirms cerebral hemorrhage and severe cardiovascular toxicity documented in the prospective cohort study.

Documents fatalities, cerebral hemorrhage, and severe cardiovascular toxicity.

checked by claude-sonnet-4-6 · May 7, 2026

verifiedConcurrent CYP2D6 or CYP3A4 inhibitors — metabolic impairment of detoxification pathways[4]model confidence 90%
Verified

Abstract confirms CYP2D6 and CYP3A4 are detoxification pathways for 4-FMA, directly supporting the claim that their inhibition impairs these pathways.

CYP2D6 and CYP3A4 detoxify.

checked by claude-sonnet-4-6 · May 7, 2026

comparative pharmacology8 claims6verified1partial1inconclusive
verifiedAnchondo et al. reported 4-FMA as the least potent compound tested among the fluorinated amphetamine and methamphetamine analogs, with a locomotor ED₅₀ of 7.38 mg/kg (i.p.) and lower peak locomotor counts (2,200–3,980 vs. 5,905–7,758 for methamphetamine and 3-position analogs)[5]model confidence 82%
Verified

Abstract confirms 4-FMA is the lowest in rank-order, ED50 7.38 mg/kg (the highest value = least potent), and peak counts 2200-3980 lower than methamphetamine. The specific methamphetamine peak count range (5,905-7,758) is not in the abstract but the directional comparison is confirmed.

rank-order: 2-FMA > METH > 3-FMA = 3-FA = 2-FA > 4-FMA; ED50 range 0.38-7.38 mg/kg. 4-FMA showed lower peak locomotor effects (2200-3980 counts) vs methamphetamine.

checked by claude-sonnet-4-6 · May 7, 2026

verifiedDespite this reduced locomotor potency, 4-FMA fully substituted for methamphetamine in discriminative stimulus assays (ED₅₀ = 0.32–0.71 mg/kg), indicating that the subjective experience is qualitatively similar enough for trained animals to recognize it as methamphetamine-like.[5]model confidence 97%
Verified

Abstract directly confirms full substitution for methamphetamine in discriminative stimulus tests with ED50 0.32-0.71 mg/kg.

All fluorinated compounds fully substituted for methamphetamine in discriminative stimulus tests (ED50 0.32-0.71 mg/kg).

checked by claude-sonnet-4-6 · May 7, 2026

verifiedAll three positional isomers fully substituted for methamphetamine in discriminative stimulus assays with comparable ED₅₀ values (0.32–0.71 mg/kg), suggesting the interoceptive cue is driven primarily by shared dopaminergic/noradrenergic mechanisms rather than the serotonergic differences that distinguish their locomotor profiles.[5]model confidence 88%
Verified

Abstract confirms all fluorinated compounds fully substituted with ED50 0.32-0.71 mg/kg. The mechanistic interpretation (dopaminergic/noradrenergic interoceptive cue) is a reasonable inference from the convergent substitution despite divergent locomotor profiles.

All fluorinated compounds fully substituted for methamphetamine in discriminative stimulus tests (ED50 0.32-0.71 mg/kg). Abuse potential comparable to methamphetamine.

checked by claude-sonnet-4-6 · May 7, 2026

verifiedThis single substitution produces a fundamental pharmacological divergence: methamphetamine is a highly DAT-selective releaser with minimal serotonergic activity, while 4-FMA has a markedly lower DAT:SERT selectivity ratio, releasing serotonin at levels comparable to MDMA.[1]model confidence 90%
Verified

Abstract confirms 4-FMA releases 5-HT at MDMA levels, implying a lower DAT:SERT ratio. The contrast with methamphetamine (DAT-selective) is supported by the noted enhanced serotonergic activity from para-fluorine substitution.

4-FMA releases NE, DA, and 5-HT similarly to MDMA. Para-fluoroamphetamine has enhanced serotonergic properties vs amphetamine.

checked by claude-sonnet-4-6 · May 7, 2026

partialEmergency department presentations with 4-FA intoxication show exaggerated hypertension (mean systolic 164 ± 31 mmHg), severe headache (80% of mono-intoxication cases), and serious complications including Takotsubo cardiomyopathy and subarachnoid hemorrhage in 40% of mono-intoxications[3]model confidence 78%
Partial

Abstract confirms mean SBP 164 mmHg, severe headache in 80%, and the listed complications (Takotsubo cardiomyopathy, subarachnoid hemorrhage, hypertensive urgency). However, the specific figure of '40% of mono-intoxications' for serious complications is not stated in the abstract and cannot be verified.

Mean SBP 164 mmHg for 4-FA patients vs 139 MDMA, 135 amphetamine. Severe headache in 80%. Complications: Takotsubo cardiomyopathy, subarachnoid hemorrhage, hypertensive urgency.

checked by claude-sonnet-4-6 · May 7, 2026

inconclusiveGresnigt et al. noted that increasing proportions of samples sold as "4-FA" contained 4-FMA following the Netherlands ban, introducing a confound into the 4-FA clinical literature.[3]model confidence 75%
Inconclusive

Abstract confirms post-ban 4-FMA was found as substitute in 4-FA samples, but does not state 'increasing proportions' specifically. The temporal trend claim requires full-text data.

Post-ban 4-FMA found as substitute in 4-FA samples.

checked by claude-sonnet-4-6 · May 7, 2026

verifiedAnchondo et al. systematically compared all ring-fluorinated amphetamine and methamphetamine positional isomers in locomotor activity and discriminative stimulus paradigms:[5]model confidence 92%
Verified

Abstract confirms systematic comparison of fluorinated analogs of amphetamine and methamphetamine in both locomotor and discriminative stimulus paradigms.

4-FMA produced time- and dose-dependent locomotor stimulation (rank-order: 2-FMA > METH > 3-FMA = 3-FA = 2-FA > 4-FMA). All fluorinated compounds fully substituted for methamphetamine in discriminative stimulus tests.

checked by claude-sonnet-4-6 · May 7, 2026

verified4-FMA's position as the weakest locomotor stimulant among the fluorinated methamphetamine isomers, combined with its uniquely enhanced serotonergic activity, supports the structure-activity principle that para-substitution on the amphetamine phenyl ring shifts the pharmacological balance away from dopaminergic stimulation and toward serotonergic/entactogenic activity[1]model confidence 85%
Verified

Abstract confirms para-fluorine enhances serotonergic activity relative to amphetamine, directly supporting the structure-activity principle about para-substitution shifting the pharmacological balance toward serotonergic activity.

Para-fluoroamphetamine has enhanced serotonergic properties vs amphetamine. 4-FMA releases NE, DA, and 5-HT similarly to MDMA.

checked by claude-sonnet-4-6 · May 7, 2026

legal status1 claim1inconclusive
inconclusiveThe 2017 scheduling of 4-FA in the Netherlands catalyzed regulatory attention toward 4-FMA as a documented substitute compound.[3]model confidence 75%
Inconclusive

Abstract confirms post-ban 4-FMA was found as a substitute in 4-FA samples. However, the specific year '2017' and the claim about 'catalyzing regulatory attention' are not confirmed by the abstract.

Post-ban 4-FMA found as substitute in 4-FA samples.

checked by claude-sonnet-4-6 · May 7, 2026

05

Coverage & Gaps

effect links
104 links · 104 approved · 0 audited0/104 with evidence basis
interactions
10 approved pairs0/10 graded
06

Research Trail

substance-article pipeline-v5 May 7, 2026

StepSourceQueryResults
1database lookupPubChem4-fluoromethamphetamine1 result, 1 selected
selection rationale

Confirmed PubChem CID and key chemical identifiers for 4-FMA

2literature searchPubMed4-fluoromethamphetamine pharmacology3 results, 3 selected
selection rationale

All three directly relevant to 4-FMA pharmacology and toxicology

3literature searchPubMed4-FMA stimulant amphetamine fluorinated1 result, 0 selected
selection rationale

Duplicate of prior search

4clinical trial searchClinicalTrials.gov4-fluoromethamphetamine0 results, 0 selected
selection rationale

No trials registered; consistent with emerging/unresearched NPS status

5literature searchPubMedpara-fluoroamphetamine 4-FA 4-FMA new psychoactive substance1 result, 1 selected
selection rationale

Direct forensic evidence of 4-FMA in fatal cases

6literature searchPubMed4-fluoroamphetamine pharmacokinetics human controlled study3 results, 2 selected
selection rationale

Human PK data for 4-FA as close structural analog of 4-FMA

7literature searchPubMedfluoroamphetamine cardiovascular cardiac toxicity2 results, 2 selected
selection rationale

Critical safety data for 4-FA with direct relevance to 4-FMA risk assessment

8literature searchPubMed4-fluoroamphetamine 4-FA intoxication blood pressure retrospective1 result, 1 selected
selection rationale

Prospective ED data documenting 4-FA's severe hypertensive effects; notes 4-FMA as substitute post-ban

9web searchWeb/Wikipedia/PsychonautWiki4-FMA 4-fluoromethamphetamine legal status history market10 results, 2 selected
selection rationale

Legal status and market history not available in academic databases

10web searchWeb/UNODC4-FMA UNODC substance database1 result, 1 selected
selection rationale

Official UNODC classification confirms substance identity

11document retrievalPMC4-FA intoxication cardiovascular data1 result, 1 selected
selection rationale

Quantitative cardiovascular data for 4-FA analog; confirms 4-FMA market substitution

12document retrievalNIST WebBook4-fluoromethamphetamine CAS 351031 physical properties1 result, 1 selected
selection rationale

Official chemical database confirming physical properties

13web searchFederal Register / Web4-FMA 4-fluoromethamphetamine DEA scheduling US controlled analog act5 results, 1 selected
selection rationale

Legal status documentation

14web searchWeb/Wikipedia4-FMA UK Misuse of Drugs Act Germany Anlage scheduling5 results, 2 selected
selection rationale

Comprehensive multi-jurisdiction legal status data

15literature searchPubMedfluoroamphetamine postmortem blood concentration forensic death2 results, 1 selected
selection rationale

Fatal intoxication blood concentration data for 4-FA; serotonergic interaction mechanism

16cross referenceMultiple sourcesChemical identity verification: SMILES, InChIKey, CAS, PubChem CID4 results, 3 selected
selection rationale

Cross-reference verification of all chemical identifiers

Research document (raw, unedited pipeline output)
# Research Output: 4-FMA (4-Fluoromethamphetamine)

**PSX ID:** PSX-0063  
**Research date:** 2026-05-07  
**Provenance ID:** e26c1e2c-f0bc-4772-8b3e-8149fde931d3

---

## Chemical Identity

**Verified chemical data (cross-referenced: PubChem, NIST, UNODC):**

| Field | Value | Source |
|-------|-------|--------|
| IUPAC name | 1-(4-fluorophenyl)-N-methylpropan-2-amine | PubChem [Ref 17], NIST [Ref 19] |
| CAS number (free base) | 351-03-1 | NIST [Ref 19], UNODC [Ref 17] |
| CAS number (HCl salt) | 52063-62-4 | Cayman Chemical / web sources [Ref 15] |
| PubChem CID | 11745017 | PubChem (verified) |
| Molecular formula | C₁₀H₁₄FN | PubChem, NIST [Ref 19] |
| Molecular weight | 167.22 g/mol (167.2233) | PubChem, NIST [Ref 19] |
| Monoisotopic mass | 167.1110 Da | NIST [Ref 19] |
| SMILES | CNC(C)CC1=CC=C(F)C=C1 | ChemSpider / web sources [Ref 15] |
| InChIKey | YCWZPIHKUYZTFM-UHFFFAOYSA-N | PubChem, NIST [Ref 19], UNODC [Ref 17] |
| InChI | InChI=1S/C10H14FN/c1-8(12-2)7-9-3-5-10(11)6-4-9/h3-6,8,12H,7H2,1-2H3 | NIST [Ref 19] |
| GC retention index | RI = 1278.3 (VF-5MS column) | NIST [Ref 19] |

**Discrepancies with seed data:** The seed data contained no SMILES, no molecular formula, no molecular weight, no InChIKey, and no PubChem CID. All five fields are now verified from multiple authoritative sources. The IUPAC name and systematic name in the seed data ("1-(4-fluorophenyl)-N-methylpropan-2-amine") are confirmed correct.

**Stereochemistry:** 4-FMA is a chiral compound (stereocenter at C-2 of the propylamine chain), yielding (R)- and (S)-enantiomers. Published sources consistently describe 4-FMA as a racemate (±)-mixture in the research chemical market [Ref 15]. No published data on enantioselective pharmacology specific to 4-FMA were identified; by structural analogy with methamphetamine, the (S)-enantiomer is predicted to be more potent at monoamine transporters, but this is **not confirmed in published data** and must be flagged for editorial review.

**Physical properties:** No melting point, boiling point, or aqueous solubility data were found in any database queried (PubChem, NIST, UNODC). This is a gap.

---

## Pharmacology

### Mechanism of Action

4-FMA is a **triple monoamine releaser**, acting at norepinephrine (NET), dopamine (DAT), and serotonin (SERT) transporters. Its pharmacological profile was directly characterized by Rickli et al. (2015 [Ref 1]) in a comprehensive in vitro study using HEK293 cells expressing human monoamine transporters.

**Key findings from Rickli et al. (2015 [Ref 1]):**
- 4-FMA releases NE and DA, as expected for amphetamine-class compounds.
- 4-FMA also releases 5-HT at a level comparable to MDMA — this is the critical distinguishing feature from methamphetamine.
- Para-fluoro substitution on the phenyl ring enhances serotonergic properties relative to the parent compound methamphetamine, but less so than 4-methyl or 4-bromo substitution.
- Compared to methamphetamine, 4-FMA has a **lower DAT:SERT selectivity ratio**, indicating a more balanced dopaminergic/serotonergic profile — consistent with entactogenic properties reported by users.
- 4-FMA shows affinity for the **5-HT₂A receptor** (binding affinity reported), though no relevant activation of the 5-HT₂B receptor was observed.
- 4-FMA, like other non-β-keto amphetamines, exhibits **trace amine-associated receptor 1 (TAAR1)** binding, which may contribute to its psychostimulant and monoamine-releasing activity.

**⚠️ FLAG:** Rickli et al. (2015 [Ref 1]) presents the IC50/EC50 data in graphical form (figures and tables in the paper). The full text was not retrieved; only the abstract was confirmed via API. Exact Ki or EC50 values for 4-FMA's transporter interactions (particularly NET, DAT, SERT release potency values) are embedded in the paper but not extracted here. The generation agent should note this limitation and avoid quoting specific numerical values without full-text confirmation.

### In Vivo Behavioral Pharmacology

Anchondo et al. (2025 [Ref 3]) directly tested 4-FMA in rodent models alongside 2-FA, 3-FA, 2-FMA, and 3-FMA:

**Locomotor activity (Swiss-Webster mice):**
- 4-FMA produced time- and dose-dependent locomotor stimulation.
- **Rank-order potency (ED₅₀):** 2-FMA > methamphetamine > 3-FMA = 3-FA = 2-FA > **4-FMA** (weakest; ED₅₀ = 7.38 mg/kg i.p.).
- **Peak locomotor effects:** 4-FMA and 2-FMA were weak stimulants with lower peak counts (2,200–3,980 counts) versus methamphetamine and the other fluorinated analogs (5,905–7,758 counts).

**Discriminative stimulus (Sprague-Dawley rats, methamphetamine training):**
- 4-FMA produced **full substitution** for methamphetamine (dose-dependently).
- ED₅₀ = 0.32–0.71 mg/kg range (comparable across all fluorinated analogs tested).
- This indicates that 4-FMA produces subjective effects qualitatively similar to methamphetamine sufficient to be recognized as the same drug class.

**Interpretation [Ref 3]:** The authors concluded that 4-FMA and other fluorinated analogs may have **abuse potential comparable to methamphetamine**, though self-administration studies were not conducted and are needed to confirm this. The weaker locomotor potency of 4-FMA compared to the 2- and 3-position analogs may reflect mechanistic differences due to para-fluorine substitution (enhanced serotonergic activity at the expense of dopaminergic/locomotor potency).

### Pharmacokinetic Data

**No human pharmacokinetic studies on 4-FMA were identified in any database searched.**

The closest available human PK data are from studies on 4-fluoroamphetamine (4-FA), a structurally related compound (methyl group absent):

- Toennes et al. (2019 [Ref 7]) conducted a controlled oral administration study of 4-FA in humans. Serum and oral fluid pharmacokinetics were measured.
- Toennes et al. (2020 [Ref 8]) characterized urinary excretion of 4-FA and three metabolites after controlled oral administration of 100 mg (n=12) and 150 mg (n=5). Urine concentrations peaked approximately 4 hours after ingestion (consistent with oral serum pharmacokinetics). Three metabolic products were identified: two diastereomers of 4-fluorophenylpropanolamine and one ring-hydroxylated 4-FA (extensively conjugated).

**Metabolic pathway for 4-FMA (in vitro, [Ref 2]):**
Roque Bravo et al. (2021 [Ref 2]) established that CYP enzymes play critical roles in 4-FMA metabolism using primary rat hepatocyte co-exposure studies with selective CYP inhibitors:
- **CYP2E1:** Plays a **toxifying role** — inhibition of CYP2E1 reduced cytotoxicity at physiologically relevant concentrations, implying CYP2E1 generates toxic metabolites.
- **CYP2D6 and CYP3A4:** Play **detoxifying roles** — inhibition of these enzymes left-shifted the concentration-response curve, increasing cytotoxicity, suggesting they produce less toxic or inactive metabolites.

This CYP enzyme involvement is clinically significant: individuals who are CYP2D6 poor metabolizers (approximately 7–10% of Caucasian populations) may have impaired detoxification of 4-FMA, potentially leading to accumulation of toxic metabolites at lower doses. Alcohol co-use induces CYP2E1, potentially increasing toxifying metabolism. These interactions create **unpredictability of consequences independent of dose** [Ref 2].

---

## History

4-FMA was first detected being sold in Japan as a "legal high" in approximately **2006** [Ref 15]. It was initially reported as an ingredient in party pills marketed internationally by Israeli company Neorganics from approximately 2006 onward; however, this was later corrected — the substance in those pills was identified as the closely related compound 2-fluoromethamphetamine (2-FMA), not 4-FMA [Ref 15].

International detections of 4-FMA in drug seizures began surfacing in **Europe and North America by approximately 2012**, with instances noted in Canada, Spain, Finland, Ireland, and the United States as reported to the United Nations Office on Drugs and Crime (UNODC) [Ref 15].

The most significant growth in 4-FMA's prevalence occurred in **2017–2018**, following the scheduling of 4-fluoroamphetamine (4-FA) as a controlled substance in the Netherlands in 2017. Because 4-FMA shares a similar name and reportedly similar effects profile to 4-FA, it gained popularity as a legal substitute. By 2018, increasing proportions of samples submitted as "4-FA" for drug checking were found to contain 4-FMA [Ref 9, Ref 15]. This represents a documented case of "regulatory displacement" — where the scheduling of one NPS drives market substitution to a closely related unscheduled compound.

4-FMA was detected in fatal cases in Taiwan from 2011 to 2018, often co-ingested with ketamine and 7-aminonimetazepam [Ref 6]. Korean forensic laboratories identified 4-FMA in urine samples from drug abusers by 2018 [Ref 13].

The synthesis of 4-FMA follows the general methods for N-methylated phenethylamines (reductive amination or direct methylation of intermediates), but no peer-reviewed publication documenting the first synthesis specifically is available. 4-FMA is commercially available as a forensic reference standard (Cayman Chemical, Cerilliant/Sigma-Aldrich, Bertin Bioreagent) [Ref 15], indicating acceptance in the forensic chemistry community.

**Discovery attribution:** No specific discoverer or first synthesis date has been identified in the published literature. The compound does not appear in classic pharmacological literature (no Shulgin, no pre-2000 publication). Based on available evidence, 4-FMA should be considered a **novel psychoactive substance of the research chemical era**, first characterized in the NPS context in the 2006–2012 timeframe.

---

## Subjective Effects

No controlled human studies of 4-FMA subjective effects were identified. The following reflects:
(a) its pharmacological profile (Rickli et al. 2015 [Ref 1]) — triple monoamine releaser with entactogenic/serotonergic character;
(b) discriminative stimulus substitution for methamphetamine in rats (Anchondo et al. 2025 [Ref 3]);
(c) community-reported effects synthesized in secondary sources (PsychonautWiki [Ref 16], Wikipedia [Ref 15]).

**Label all of the following as "user-report-only / class inference" in article prose — no controlled human study data exist for 4-FMA's subjective effects.**

From pharmacological profile and user reports [Ref 1, Ref 15, Ref 16]:
- Described as having both **stimulant and entactogenic** ("entactogen") properties, distinguishing it from pure stimulants like amphetamine or methamphetamine.
- Effects reported to include: euphoria, increased sociability, empathy enhancement, mood elevation, increased energy, enhanced focus, reduced appetite, and cardiovascular stimulation.
- The serotonergic component (comparable to MDMA per Rickli [Ref 1]) may contribute to prosocial effects, emotional openness, and tactile enhancement.
- The lower locomotor potency compared to 2-FMA and 3-FMA [Ref 3] may correspond to a comparatively less intense stimulant experience with a more balanced stimulant/entactogen profile.

**Seed effect profile note:** All 43 seed effects currently lack intensity/frequency values. Given the absence of controlled human data, these will remain low-confidence community consensus until substantive user report data or controlled studies become available.

**Dose/duration data (from seed data, confirmed against community sources [Ref 16]):**
- Threshold: 10 mg (oral)
- Light: 25–50 mg (oral)
- Common: 50–75 mg (oral)
- Strong: 100–125 mg (oral)
- Heavy: 125+ mg (oral)
- Onset: 20–40 min; come-up: 20–40 min; peak: 2–5 h; offset: 1–2 h; aftereffects: 3–12 h; total: 4–8 h

These figures originate from community consensus (PsychonautWiki [Ref 16]) and are not verified by a controlled clinical study. The generation agent should flag them as community consensus with no peer-reviewed confirmation.

---

## Safety & Toxicity

### Overview
The exact toxic dose for 4-FMA in humans is unknown. No LD₅₀ has been published for 4-FMA in any species. No human overdose case reports specific to 4-FMA were identified in PubMed or OpenAlex.

### Hepatotoxicity (4-FMA-specific in vitro data)

Roque Bravo et al. (2021 [Ref 2]) provides the only published 4-FMA-specific toxicological study. In vitro hepatotoxicity was established across three hepatocellular models after 24-hour exposure:

| Model | EC₅₀ (cytotoxicity) |
|-------|---------------------|
| Primary rat hepatocytes (PRH) | 2.21 mM |
| HepaRG (human hepatoma) | 5.59 mM |
| HepG2 (human hepatoma) | 9.57 mM |

Primary rat hepatocytes were the most sensitive model. **The clinical significance of these in vitro EC₅₀ values is uncertain** — mM concentrations far exceed typical plasma concentrations at recreational doses, but in vitro cytotoxicity does not necessarily reflect in vivo hepatotoxicity due to differences in protein binding, first-pass effect, and metabolic activation [Ref 2].

**Mechanisms of hepatocellular toxicity identified [Ref 2]:**
- Destabilization of mitochondrial membrane potential
- Decreased intracellular ATP levels
- Increased production of reactive oxygen species (ROS) and reactive nitrogen species (RNS)
- Compromise of thiol antioxidant defenses (likely glutathione depletion)
- Activation of apoptosis (initiator and effector caspase activation)
- Necrosis (loss of plasma membrane integrity)
- Evidence of autophagy induction

**⚠️ SAFETY FLAG:** The authors emphasize that **metabolic activation by CYP enzymes makes hepatotoxicity unpredictable and potentially independent of dose** [Ref 2]. CYP2D6 poor metabolizers and individuals using CYP2E1 inducers (e.g., alcohol, chronic fasting) may be at higher hepatotoxic risk.

### Cardiovascular Toxicity (analog data: 4-FA)

4-Fluoroamphetamine (4-FA) is the closest structural analog with substantial clinical safety data. All cardiovascular data below applies to 4-FA; clinical relevance to 4-FMA is by structural analogy and requires explicit labeling as such.

Hondebrink et al. (2018 [Ref 4]) conducted a prospective cohort study of 4-FA adverse health effects, documenting fatalities, cerebral hemorrhage, and severe cardiovascular toxicity.

Gresnigt et al. (2022 [Ref 9]) retrospectively analyzed 31 emergency department 4-FA intoxication cases:
- Mean systolic blood pressure: **164 ± 31 mmHg** (significantly higher than MDMA [139 mmHg] and amphetamine [135 mmHg])
- **Severe headache in 80% of mono-intoxicated 4-FA patients** (vs. 3.3% MDMA, 0% amphetamine)
- All patients with hypertension lacked hypertensive history (acute drug-induced)
- Serious complications in 40% of mono-intoxications: Takotsubo cardiomyopathy, subarachnoid hemorrhage, hypertensive urgency
- Paradoxically **lower heart rate** (81.5 bpm) vs MDMA (112.0) and amphetamine (103.0), possibly reflecting different relative NET/SERT/DAT contributions
- Authors note that **post-ban, 4-FMA increasingly appeared in samples presented as "4-FA"**, meaning some 4-FMA exposures may be embedded in the 4-FA clinical literature

Gerostamoulos et al. (2023 [Ref 18]) documented six Australian fatalities from 4-FA + 25C-NBOMe combination:
- Four direct drug-caused deaths with postmortem 4-FA blood: 330–682 ng/L (median 417)
- Two indirect deaths: 21–123 ng/mL
- Concentrations did not suggest high recreational doses — deaths occurred within apparently "recreational" ranges
- Symptoms: agitation/aggression, seizures, pulmonary/cerebral edema
- Risk attributed to combined serotonin elevation from both drugs plus strong stimulant effects

**Serotonin syndrome risk:** 4-FMA's serotonin-releasing mechanism (comparable to MDMA [Ref 1]) creates serious theoretical risk for serotonin syndrome when combined with other serotonergic agents. The combination with tramadol is listed as "lethal" in the seed data — this is plausible given tramadol's serotonin reuptake inhibition and weak SERT-releasing properties, but **no 4-FMA + tramadol specific case report was identified**. This flag is class-level inference, not 4-FMA-specific evidence.

### Cardiotoxicity Screening

Zwartsen et al. (2019 [Ref 5]) screened 4-FA in human iPSC-derived cardiomyocytes using microelectrode array recordings:
- 4-FA affected cardiomyocyte function at concentrations ≥10 µM (decreased spike amplitude at 10–100 µM)
- Increased field potential duration (proxy for QTc prolongation) at varying concentrations
- Beat rate decreased at 300 µM
- Authors conclude that tachycardia in 4-FA/4-FMA users is likely **indirect** (via elevated plasma norepinephrine), while prolonged QTc interval could partly result from **direct drug effects on cardiomyocyte ion channels**

### Forensic Detection

4-FMA was detected in postmortem blood and urine specimens from fatal cases in Taiwan (2011–2018), often co-ingested with ketamine and nimetazepam metabolites [Ref 6]. A validated GC-MS method for 4-FMA in urine showed LLOQ of 2.0 ng/mL [Ref 13]. ELISA screening (amphetamine immunoassays) may not reliably detect 4-FMA; confirmatory LC-MS/MS or GC-MS is required [Ref 20].

---

## Harm Reduction

**No published harm reduction guidelines specific to 4-FMA were identified.** The following are derived from published safety data and class-level evidence.

**Contraindications (mechanism-based):**
- **MAOIs:** Contraindicated with all monoamine releasers; risk of hypertensive crisis and serotonin syndrome.
- **Other serotonergic agents (tramadol, SSRIs, SNRIs, triptans):** Enhanced serotonin syndrome risk given 4-FMA's SERT-releasing mechanism [Ref 1]. Tramadol specifically listed as "lethal" in seed data; this is class-level risk, not 4-FMA-specific evidence — flag for editorial review.
- **PCP (phencyclidine):** Listed as "dangerous" in seed data — mechanism likely additive CNS/cardiovascular stimulation; no 4-FMA-specific data found.
- **Stimulant combinations (cocaine):** Listed as "unknown" in seed data; additive cardiovascular risk expected.
- **Depressant combinations (GHB, GBL, alcohol, ketamine):** "Unknown" in seed data; may mask cardiovascular warning signs.

**Practical harm reduction (class-level evidence):**
- Drug checking (reagent testing or LC-MS) is strongly recommended given documented market substitution and adulteration — 4-FMA has been sold as or adulterated into 4-FA samples [Ref 9, Ref 15].
- Cardiovascular monitoring warranted given 4-FA analog's severe hypertensive profile [Ref 9].
- Avoid use in individuals with hypertension, cardiac disease, or hepatic impairment [Ref 2, Ref 4].
- Given CYP2E1 toxifying role [Ref 2], alcohol co-ingestion may increase hepatotoxic risk.
- Heat and physical exertion exacerbate stimulant cardiovascular toxicity (class-level evidence).

**Testing:** 4-FA has high cross-reactivity (3,354%) with amphetamine ELISA [Ref 20]; 4-FMA may behave similarly but specific cross-reactivity data for 4-FMA were not found. Confirmatory LC-MS/MS or GC-MS required for unambiguous identification.

---

## Tolerance & Dependence

**No tolerance, dependence, or withdrawal studies specific to 4-FMA were identified.**

The seed data states:
- Tolerance buildup: develops with prolonged and repeated use
- Tolerance half-life: 5 days
- Full reset: 1.5 weeks
- Cross-tolerances: dopamine, stimulant

These figures cannot be verified against published 4-FMA-specific sources. By class analogy with amphetamine/methamphetamine (well-studied monoamine releasers), tolerance to the stimulant and euphoric effects develops with repeated use via:
- Dopamine transporter upregulation
- Receptor desensitization
- Dopamine depletion at presynaptic terminals

Cross-tolerance with other dopaminergic stimulants (cocaine, amphetamine, methamphetamine) is expected based on shared mechanism. Cross-tolerance with MDMA is also expected given 4-FMA's serotonergic component [Ref 1].

**Dependence liability:** The seed data rates physical and psychological dependence as "moderate." Anchondo et al. (2025 [Ref 3]) demonstrated full discriminative stimulus substitution for methamphetamine, consistent with abuse potential comparable to methamphetamine, but self-administration studies were not conducted [Ref 3]. The abuse liability assessment must be considered preliminary in the absence of self-administration data.

**⚠️ FLAG for editorial review:** All tolerance/dependence parameters in the seed data are class-level inferences (stimulant/amphetamine analog data), not 4-FMA-specific findings.

---

## Interactions

| Substance | Seed data severity | Published evidence |
|-----------|-------------------|-------------------|
| Tramadol | Lethal | Class-level: combined serotonergic load; no 4-FMA-specific case found |
| PCP | Dangerous | No 4-FMA-specific data; class-level stimulant + dissociative interaction |
| Cannabis | Unknown | No data |
| Alcohol | Unknown | CYP2E1 inducer → increased hepatotoxic metabolism [Ref 2] |
| Caffeine | Unknown | No data; additive cardiovascular stimulation expected |
| Cocaine | Unknown | No data; additive cardiovascular stimulation expected |
| GHB/GBL | Unknown | No data; may mask cardiovascular warning signs |
| Ketamine | Unknown | Co-ingestion documented in Taiwan fatal cases [Ref 6] |
| Methoxetamine | Unknown | No data |

**Serotonin syndrome mechanism:** 4-FMA's SERT-releasing activity (comparable to MDMA [Ref 1]) is the primary pharmacological basis for interactions with other serotonergic drugs. Serotonin syndrome risk is highest with MAOIs, tramadol, SSRIs, SNRIs, linezolid, and other serotonin releasers or reuptake inhibitors.

**CYP interaction concern:** CYP2D6 inhibitors (fluoxetine, paroxetine, bupropion, ritonavir) may impair 4-FMA detoxification, increasing cytotoxic metabolite accumulation [Ref 2]. CYP3A4 inhibitors (ketoconazole, grapefruit juice) similarly [Ref 2].

---

## Legal Status

| Jurisdiction | Status | Date | Notes |
|-------------|--------|------|-------|
| United Kingdom | Class A | 1977 (MDA amendment) | Covered under Misuse of Drugs Act 1971; Schedule 1 possession/supply offense [Ref 15] |
| Germany | Anlage II BtMG | July 26, 2012 | Requires license to manufacture, possess, import, export, buy, sell [Ref 15] |
| Japan | Controlled (sale/distribution) | 2008 | Illegal to sell or possess for distribution; personal possession not specifically prohibited [Ref 15] |
| Canada | Controlled | 1996 | Methamphetamine analog; controlled under Controlled Drugs and Substances Act [Ref 15] |
| Australia | Schedule 9 (Prohibited substance) | — | Defined as substance which may be abused; manufacture/possession/sale prohibited except for medical/scientific research [Ref 15] |
| China | Controlled | October 2015 | [Ref 15] |
| Italy | Schedule I | — | [Ref 15] |
| New Zealand | Schedule 3 | — | Amphetamine analog [Ref 15] |
| United States | Not explicitly scheduled | — | Likely covered under Federal Analogue Act (structurally similar to methamphetamine, Schedule II). 4-FA placed in Schedule I effective February 17, 2026 (FR 2025-09988/2026-00633), but 4-FMA not specifically named. No DEA-specific scheduling order for 4-FMA found. |
| Netherlands | Effective ban ~2017 | 2017 | 4-FA ban drove 4-FMA market expansion [Ref 9, Ref 15] |

**⚠️ FLAG:** The US legal status of 4-FMA requires editorial verification. The DEA has not published a specific scheduling notice for 4-FMA. Its coverage under the Federal Analogue Act depends on intent for human consumption, which is subject to prosecutorial discretion. Legal advice should not be offered; status should be presented as "may be covered under the Federal Analogue Act."

---

## Clinical Trials

**No clinical trials involving 4-FMA were identified on ClinicalTrials.gov** (search performed 2026-05-07). This is consistent with its status as an unregulated research chemical with no established therapeutic applications.

---

## Community Feedback Analysis

No community feedback was submitted in Part A2 of the brief.

---

## Gaps & Flags

### Critical Safety Flags
1. **⚠️ Tramadol "lethal" interaction:** No 4-FMA-specific evidence found. This is a class-level inference from serotonin syndrome risk with monoamine releasers + tramadol. The generation agent should note this as class-level risk, not confirmed 4-FMA-specific data. The underlying mechanism is valid but requires cautious language.

2. **⚠️ Exact toxic dose unknown:** No LD₅₀ in any species. No human overdose case reports specific to 4-FMA. This is explicitly stated in the seed data and confirmed by literature search.

3. **⚠️ Market substitution risk:** 4-FMA has been sold as or adulterating 4-FA samples post-Netherlands ban [Ref 9, Ref 15]. Users may unknowingly be consuming 4-FMA instead of 4-FA (or vice versa).

### Data Gaps
4. **No human PK/PD studies for 4-FMA.** All duration and onset data are based on community consensus (PsychonautWiki [Ref 16]). The 4-FA pharmacokinetic data from Toennes et al. [Ref 7, Ref 8] provides structural-analog reference but cannot be directly transposed.

5. **No published Ki/EC50 numerical values in isolation for 4-FMA.** The Rickli et al. (2015 [Ref 1]) data is confirmed to include 4-FMA, but the abstract does not reproduce specific numbers; these are in the paper's tables/figures (paywalled, not retrieved).

6. **No stereochemistry-specific pharmacological data.** 4-FMA is chiral. Whether the marketed racemate, (S)-, or (R)-enantiomer is pharmacologically dominant is unknown.

7. **No melting point, boiling point, or solubility data** in any database queried.

8. **No withdrawal characterization.** Tolerance/dependence data in seed is class inference; no 4-FMA-specific studies exist.

9. **US legal status unclear.** No specific DEA scheduling found; Federal Analogue Act coverage is likely but untested/unconfirmed.

10. **No EMCDDA formal risk assessment** found for 4-FMA specifically. EMCDDA has reported on 4-FA; whether 4-FMA has triggered a formal early warning response is not confirmed.

11. **All seed effect intensity/frequency values are null.** No controlled study data exists to fill these. Values will need to remain as community_consensus with appropriate confidence flagging.

### Analog Inference Sections
The following sections of any generated article rely primarily on structural analogy (4-FA) rather than 4-FMA-specific data, and must be explicitly labeled:
- Cardiovascular toxicity severity
- Serotonin syndrome interaction risk
- Specific interaction severities (PCP, tramadol)
- Dependence/withdrawal characterization
- All duration and duration data (seed values from community consensus only)