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6-APDB

6-(2-aminopropyl)-2,3-dihydrobenzofuran

Overview

6-APDB (4-Desoxy-MDA) is a synthetic empathogen of the substituted benzofuran class. It is a structural analog of MDA with MDMA-like emotional and social effects. It floods the brain with serotonin, norepinephrine, and dopamine — driving the emotional warmth characteristic of entactogens.[1]

6-APDB (1-(2,3-dihydro-1-benzofuran-6-yl)propan-2-amine) — also known as 4-Desoxy-MDA — is a synthetic empathogen of the substituted benzofuran class. It is a structural analog of MDA with the methylenedioxy oxygen replaced by a methylene bridge. 6-APDB is a triple monoamine releasing agent, producing its effects by reversing serotonin, norepinephrine, and dopamine transporters with preferential serotonergic activity.[1]

Entity
6-APDB
PSX-0085
6-APDB 2D chemical structure
Open Beta

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NoticeAll →
•2 lethal interactions(all →)
Common names6-APDB
Substitutive name6-(2-aminopropyl)-2,3-dihydrobenzofuran
Threshold
< 20 mg
Light
30 – 70 mg
Common
70 – 100 mg
Strong
100 – 130 mg
Heavy
130+ mg
12340 h2 h4 h6 h7 h
1Onset
30m–1h2Come-up
30m–1h3Peak
2h–3h4Resolution
2h–3hAftereffects12h–24h
Total6h–8h
Buildupmoderate
Full reset75 days
Cross-tol.
MDMA, MDA, 6-APB +3 more
Absolute3 entries
cardiac valve diseasepulmonary arterial hypertensionpregnancy and breastfeeding
Relative5 entries
uncontrolled hypertensionepilepsybipolar disorderpsychotic disordershepatic impairment
Dosage varies by body weight, tolerance & metabolism · Not medical advice · Terms
See an error? Suggest correction
See an error? Suggest correction

6-APDB was first synthesized in 1993 by Nichols and colleagues as part of a search for MDA analogs that kept entactogenic effects without neurotoxic risk.[2] It stayed in the laboratory for over fifteen years, then appeared on European research chemical markets as an MDMA substitute, sold as part of "benzofury" blends.[3] The UK scheduled it as Class B in 2013; it has no medical use and is rarely encountered today.

Subjective effects include emotional warmth, empathy enhancement, tactile euphoria, mild stimulation, and subtle perceptual shifts. The experience is MDMA-like in character — emotional openness dominates over stimulation — but builds more slowly and lasts longer.[4] Compulsive urges to redose are common, and the days following typically bring depressed mood and fatigue as serotonin stores rebuild.

No physical dependence has been documented, but 6-APDB carries a cardiac risk absent from MDMA — repeated use activates a receptor that causes heart valves to thicken and scar over time.[1][5] The damage accumulates silently, and combining it with antidepressants or other serotonergic drugs risks a dangerous overheating and seizure response.[6] No human studies have been conducted; everything known comes from lab pharmacology, animal data, and structural analogy to MDMA.

History[edit]

Discovery

6-APDB was first synthesized in 1993 by Nichols and colleagues as part of a search for MDA analogs that preserved entactogenic effects while avoiding the oxidative metabolic pathway linked to serotonin nerve damage.[2] By replacing the oxygen atoms in MDA's ring system with a methylene bridge, they created what they called a "nonoxygenated isostere" — structurally related to MDA but theoretically resistant to its toxic pathway.[2]

Research chemical era

The compound remained in the laboratory for over fifteen years. It appeared on European research chemical markets in the late 2000s alongside benzofuran relatives, sold under the name "benzofury" as an MDMA substitute.[3] All pharmacological knowledge beyond the original 1993 paper comes from lab receptor studies[1] and animal behavioral tests[4] — no controlled human studies have ever been conducted.

Prohibition

The UK placed 6-APDB under a Temporary Class Drug Order in June 2013, then permanently scheduled it as Class B under a generic benzofuran definition.[7][8] Its cardiac risks and controlled status have kept it out of the entactogen therapy research pipeline.[9]

Chemistry[edit]

Structural class

6-APDB belongs to the phenethylamine, amphetamine, and dihydrobenzofuran chemical classes.[2] It is a structural analog of MDA — one oxygen in MDA's ring system has been replaced with a methylene bridge, forming a dihydrobenzofuran scaffold.

This relationship is why the compound is also called 4-Desoxy-MDA, and it places 6-APDB in the same structural family as 6-APB, the unsaturated version of the same scaffold.

Molecular properties

Molecular formulaC₁₁H₁₅NO
Molecular weight177.24 g/mol

The compound has moderate lipophilicity (XLogP 1.7).[10]

Pharmacology[edit]

Mechanism of action

6-APDB enters monoamine neurons and forces their reuptake transporters to run in reverse, flooding the synapse with serotonin, norepinephrine, and dopamine.[1] This is the same releasing mechanism as MDMA. Serotonin is released most strongly — the same ordering as MDMA and opposite to methamphetamine, which prioritizes dopamine.

6-APDB also activates a receptor called 5-HT₂B — a property MDMA does not share.[1] Chronic activation of this receptor is how fenfluramine caused heart valve scarring before it was withdrawn from the market.[5][11] This is the defining pharmacological difference between 6-APDB and MDMA.

Pharmacokinetics

No human pharmacokinetic data exist for 6-APDB. Metabolism is inferred from structural analogy to MDMA and related benzofurans — liver enzymes including CYP2D6 are likely involved, but this has not been confirmed.[12]inferred Community reports suggest onset of 30–60 minutes and total duration of 6–8 hours.citation needed

Neuroscience[edit]

Where it acts

The serotonin flood suppresses threat-response circuitry in the brain, producing emotional openness and reduced social anxiety. The dopamine component activates the brain's mesolimbic pathway, adding stimulation and euphoria.[4] Together, these produce the entactogenic state — emotional warmth with reduced defensiveness.

Why it matters

This emotional openness with reduced fear is what made benzofuran entactogens therapeutically interesting — the same brain state researchers are trying to harness in MDMA-assisted therapy.[2][9] The original synthesis aimed to replicate MDMA's prosocial effects without its neurotoxic metabolic pathway.

Subjective Effects[edit]

Summary

6-APDB is defined by serotonin. Emotional warmth and interpersonal openness fill the foreground, with stimulation and mild perceptual shifts secondary. The experience has a sustained, unhurried quality — less peaking than MDMA, more like a slow emotional opening that holds for hours.

Within the entactogen class, 6-APDB sits closest to MDMA in character but follows a slower arc.[4] It is structurally an structural analog of MDA, but the subjective experience reads as MDMA-like — emotional warmth over stimulation, closeness over psychedelic intensity.citation needed

Synthesized in 1993 by Nichols and colleagues at Purdue University as part of a search for non-neurotoxic MDA alternatives,[2] the compound remained a laboratory curiosity until the late 2000s when it appeared on European research chemical markets as an MDMA substitute. It is now controlled as Class B in the United Kingdom and subject to analogue legislation in several other jurisdictions.

Subjective effects include empathy enhancement, tactile euphoria, stimulation, and mild perceptual distortion. The experience is MDMA-like in character — emotional warmth and interpersonal openness dominating over stimulation — but builds more slowly and persists longer than its better-known relative.[3] Compulsive redosing urges and a post-experience mood dip from serotonin depletion are common unsought effects.

No physical dependence has been documented, but 6-APDB carries a specific cardiovascular toxicity absent from MDMA: potent 5-HT₂B receptor agonism linked to heart valve damage upon repeated use.[1][4] Unlike acute serotonergic risks shared across entactogens, this valvulopathy hazard is cumulative — damage accrues silently over repeated exposures with no warning symptoms until structural changes are established.[5] No clinical studies have been conducted; the current understanding rests entirely on in vitro pharmacology, animal behavioral data, and structural analogy to MDMA.

History[edit]

Discovery

6-APDB was first synthesized and characterized in 1993 by A.P. Monte, D. Marona-Lewicka, N.V. Cozzi, and D.E. Nichols at Purdue University.[2] The compound — designated "compound 6" in the original paper — emerged from a structure-activity investigation of MDA analogs aimed at separating entactogenic effects from neurotoxicity. By replacing both oxygen atoms of MDA's methylenedioxy ring with a methylene bridge forming a dihydrobenzofuran system, the researchers created what they termed a "nonoxygenated isostere" — structurally related to MDA but theoretically resistant to the oxidative metabolic pathway implicated in serotonergic neurotoxicity.[2]

Research chemical era

6-APDB remained exclusively a laboratory compound for over fifteen years after its synthesis. It entered recreational circulation in the late 2000s to early 2010s as part of the European novel psychoactive substance wave, sold alongside its positional isomer 5-APDB and the unsaturated analogs 5-APB and 6-APB under marketing names including "benzofury".[6] No controlled human studies were conducted during this period — all pharmacological knowledge beyond the 1993 paper derives from in vitro receptor profiling[1] and animal behavioral studies.[3]

Prohibition

Regulatory response was swift. On 10 June 2013, the UK Advisory Council on the Misuse of Drugs placed 6-APDB under a Temporary Class Drug Order alongside the other benzofuran entactogens.[7] Later that year, permanent Class B scheduling using a generic benzofuran definition eliminated the market in the UK.[8] The compound's serotonin₂B agonism and controlled status have excluded it from the entactogen-assisted psychotherapy research pipeline that has advanced MDMA toward clinical approval.[9]

Chemistry[edit]

Structural class

6-APDB belongs to the phenethylamine, amphetamine, and dihydrobenzofuran chemical classes. It is the saturated (2,3-dihydro) structural analog of 6-APB, and a direct structural analog of MDA in which the methylenedioxy oxygen at the 4-position has been replaced by a methylene bridge, closing the ring into a dihydrobenzofuran system.[2] This relationship is reflected in its alternate name 4-Desoxy-MDA.

Within the benzofuran series, the "6" designates the position of the aminopropyl side chain on the benzofuran ring, distinguishing it from the 5-positional isomer 5-APDB. Both isomers were synthesized and characterized in the same 1993 publication.[2]

Molecular properties

Molecular formulaC₁₁H₁₅NO
Molecular weight177.24 g/mol

The compound has moderate lipophilicity (XLogP 1.7).[10]

Stereochemistry

The α-methyl group on the propylamine side chain creates a chirality center, producing R and S enantiomers. No published data address 6-APDB's stereospecific pharmacology directly. Indirect evidence from structurally related benzofuran derivatives suggests the S-isomer functions as an efficacious triple monoamine releaser at all three transporters, while the R-isomer preferentially releases serotonin with diminished dopaminergic activity.[11] Whether this pattern extends to 6-APDB has not been tested.

Physical properties

No melting point, solubility, or salt-form characterization data have been published in peer-reviewed literature. The compound is available from research chemical suppliers in freebase and hydrochloride salt forms. No stability or degradation pathway studies have been published.

Pharmacology[edit]

Mechanism of action

6-APDB works by entering monoamine neurons through their reuptake transporters and forcing the transporters to run in reverse, flooding the synapse with serotonin, norepinephrine, and dopamine. This substrate-type releasing mechanism is shared with MDMA.[1] The selectivity profile favors serotonin release over norepinephrine and dopamine — the same ordering as MDMA and opposite to methamphetamine, which preferentially releases dopamine.[1]

Beyond transporter reversal, 6-APDB acts at several receptor targets. It partially activates 5-HT₂A receptors, likely contributing to mild perceptual effects and empathogenic qualities. It activates TAAR1 (trace amine-associated receptor 1), which modulates monoamine neuron firing — a feature shared with classical amphetamines.[1]

Critically, 6-APDB is a potent agonist at 5-HT₂B receptors — a property that distinguishes it from MDMA, which does not significantly activate this receptor.[1] Chronic 5-HT₂B activation is the mechanism by which fenfluramine and ergotamine caused cardiac valve fibrosis.[4][12]

In animal behavioral studies, 6-APDB fully substituted for MDMA's discriminative cue in trained rats and produced locomotor stimulation in mice, but did not substitute for methamphetamine, cocaine, or DOM — confirming an MDMA-like rather than classical stimulant or psychedelic profile.[3]

Pharmacokinetics

No human pharmacokinetic studies exist for 6-APDB. Plasma half-life, bioavailability, volume of distribution, and metabolic pathways have not been characterized in humans.

Metabolic data from the structural analog 5-APB provide limited extrapolation: the related compound 5-MAPB is metabolized by liver enzymes including CYP2B6 and CYP2D6.[13] By structural analogy to MDMA, CYP2D6 is likely involved in 6-APDB's metabolism, but this remains inferential.inferred

Community-reported oral data suggest an onset of 30–60 minutes, peak effects at 2–3 hours, and total duration of 6–8 hours.citation needed No pharmacokinetic modeling exists to correlate these subjective timelines with plasma concentrations.

Neuroscience[edit]

Where it acts

6-APDB's entactogenic effects arise from serotonin flooding the amygdala and prefrontal cortex, suppressing threat-response circuitry and facilitating prosocial emotional processing. The dopaminergic component activates the brain's mesolimbic pathway (ventral tegmental area to nucleus accumbens), producing stimulation and euphoria.[3] TAAR1 activation modulates dopamine neuron firing rates, potentially limiting the reinforcing "wanting" quality compared to pure stimulants.[1][14]

Why it matters

The entactogenic state — emotional openness with reduced fear — aligns with the memory reconsolidation framework applied to MDMA therapy: serotonin-mediated fear extinction enables access to aversive memories without the associated threat response.[2][9] The original benzofuran synthesis program was motivated precisely by this therapeutic potential, seeking compounds that could replicate MDMA's prosocial effects without its neurotoxic metabolic pathway.

Subjective Effects[edit]

Summary

6-APDB's experiential character is defined by serotonergic dominance: emotional openness, interpersonal warmth, and reduced social anxiety form the core of the experience across the active dose range, with stimulation and mild perceptual shifts as secondary features. At lower doses the experience is gentle and social; higher doses bring stronger perceptual effects and more pronounced physical stimulation. Set and setting exert substantial influence, particularly during the comedown phase where serotonin depletion can amplify pre-existing mood states.

Within the entactogen class, 6-APDB sits between MDMA and MDA — structurally an MDA structural analog with MDMA-like subjective character,[3] but with a slower onset arc and longer total duration that gives the experience a more sustained, less peaking quality than MDMA.citation needed

Effect Grid

Dose Level:
Description

At common doses (70–100 mg oral), the full entactogenic experience manifests: pronounced empathy enhancement, emotional openness, tactile euphoria, and a strong sense of interpersonal connection. Music enhancement becomes prominent. Thought acceleration, creativity enhancement, and immersion enhancement are characteristic. Mild perceptual effects may appear — visual haze, subtle tracers, enhanced color saturation — though substantially less intense than classical psychedelics.

Physically, stimulation is marked: increased heart rate, bruxism, pupil dilation, increased sweating, temperature dysregulation, and appetite suppression. Spontaneous body sensations and bodily lightness are commonly reported.

Sleep is impossible for approximately 6–8 hours. The experience demands a committed time window and is incompatible with responsibilities requiring focused cognition.

Modeled from the effect's dose-dependence curve — not per-substance measurements.

Perception(20)likelihood · intensity
Music enhancement
likely
Touch enhancement
possible
Auditory enhancement
possible
Color enhancement
possible
Light sensitivity
possible
Tracers
possible
Visual haze / noise
possible
Dreaming enhancement
possible
Sound sensitivity
possible

Tracers · Visual haze / noise · Dreaming enhancement · Sound sensitivity · Symmetrical texture repetition · Peripheral misidentification · Color alteration · After-images · Environmental patterning · Geometry · Synesthesia · Visual breathing · Visual drifting · External hallucinations · Internal hallucinations

Symmetrical texture repetition · Peripheral misidentification · Color alteration · After-images · Environmental patterning · Geometry · Synesthesia · Visual breathing · Visual drifting · External hallucinations · Internal hallucinations

Body(36)likelihood · intensity
Body scan awareness
likely
Stimulation
likely
Body high
likely
Pupil dilation
likely
Wakefulness
likely
Appetite suppression
likely
Temperature dysregulation!
possible
Vasoconstriction!
possible
Motor control impairment!
possible

Pupil dilation · Wakefulness · Appetite suppression · Physical fatigue · Excessive sweating · Tactile euphoria · Spontaneous body sensations · Dry mouth · Heart rate perception changes · Bodily lightness · Bruxism · Dehydration sensation · Insomnia · Muscle tension · Restlessness · Tingling / electric sensations · Sexual arousal enhancement · Headache · Laughter fits · Nausea · Nystagmus (eye wobbles) · Vibrations / buzzing · Dizziness · Motor control impairment · Sexual arousal suppression · Increased urination · Abnormal heartbeat · Brain zaps · Trembling · Motor control enhancement · Vomiting

Physical fatigue · Excessive sweating · Tactile euphoria · Spontaneous body sensations · Dry mouth · Heart rate perception changes · Bodily lightness · Bruxism · Dehydration sensation · Insomnia · Muscle tension · Restlessness · Tingling / electric sensations · Sexual arousal enhancement · Headache · Laughter fits · Nausea · Nystagmus (eye wobbles) · Vibrations / buzzing · Dizziness · Sexual arousal suppression · Increased urination · Abnormal heartbeat · Brain zaps · Trembling · Motor control enhancement · Vomiting

Thinking(25)likelihood · intensity
Cognitive euphoria
likely
Openness enhancement
likely
Cognitive fatigue
possible
Aesthetic enhancement
possible
Introspection enhancement
possible
Immersion enhancement
possible
Decision impairment!
possible
Suggestibility enhancement!
possible
Compulsive redosing urge!
possible

Aesthetic enhancement · Introspection enhancement · Immersion enhancement · Cognitive flexibility · Novelty enhancement · Humor enhancement · Compulsive redosing urge · Creativity enhancement · Thought acceleration · Motivation suppression · Motivation enhancement · Pattern recognition enhancement · Cognitive impairment · Language enhancement · Thought connectivity · Focus enhancement · Increased nature relatedness · Thought deceleration · Confusion · Memory replays

Cognitive flexibility · Novelty enhancement · Humor enhancement · Creativity enhancement · Thought acceleration · Motivation suppression · Motivation enhancement · Pattern recognition enhancement · Cognitive impairment · Language enhancement · Thought connectivity · Focus enhancement · Increased nature relatedness · Thought deceleration · Confusion · Memory replays

Feeling(13)likelihood · intensity
Euphoria
likely
Empathy enhancement
likely
Emotional enhancement
likely
Anxiety suppression
possible
Depression!
possible
Emotional lability
possible
Irritability
possible
Catharsis
possible
Paranoia!
rare

Anxiety suppression · Emotional lability · Irritability · Catharsis · Simultaneous emotions · Anhedonia · Anxiety · Dysphoria

Simultaneous emotions · Anhedonia · Anxiety · Dysphoria

Self(10)likelihood · intensity
Social connection
likely
Trust enhancement
likely
Sociability enhancement
likely
Disinhibition
possible
Emotional susceptibility
possible
Communication enhancement
possible
Flow state
possible
Craving
possible
Self-control suppression!
rare

Emotional susceptibility · Communication enhancement · Flow state · Craving · Boundary dissolution

Boundary dissolution

Time(2)likelihood · intensity
Present-moment absorption
possible
Time alteration
possible
Transpersonal(4)likelihood · intensity
Unity and interconnectedness
possible
Existential realization
v.rare
Noetic insight
v.rare
Transpersonal feelings
v.rare
Awareness(2)likelihood · intensity
Personal insight
possible
Mindfulness enhancement
possible
report missing effect
Likelihood: how common this effect is at the selected dose level.This effect has safety implications — review before use.

Timeline

Safety[edit]

Harm
Acute toxicity
Low
Chronic toxicity
Moderate
Withdrawal
None
Tolerance buildup
moderate
Tolerance reset
75 days
Dependence
Physical
Negligible
Psychological
Low
Compulsive redosing
Moderate
Dose escalation
Low
Cross-tol.
MDMA · MDA · 6-APB
Risk Shape
TOXPHYPSYWDRREDTOL

Toxicity

No lethal dose has been established for 6-APDB in any species, and no overdose fatalities specific to 6-APDB appear in the indexed literature.

Cardiovascular toxicity

6-APDB activates a receptor called serotonin₂B.[1] Chronic activation of this receptor causes heart valves to thicken and scar — the same mechanism that led to fenfluramine being pulled from the market.[5][11] This risk is specific to repeated use and is not shared with MDMA. The damage accumulates silently — no symptoms appear until structural change is already established.[6] The cumulative exposure threshold required to cause detectable damage is unknown.

The mechanism is direct: 5-HT₂B activation promotes tissue growth in heart valve cells, causing fibrotic thickening.[14]

Serotonin toxicity

As a potent serotonin releaser, 6-APDB carries significant serotonin syndrome risk when combined with other serotonergic agents. This response is potentially life-threatening: body temperature spikes dangerously, muscles jerk involuntarily, the heart races, and without treatment the result can be organ failure.safety citation needed

Neurotoxicity

The original synthesis aimed to produce a non-neurotoxic compound by modifying the ring oxygens implicated in MDA and MDMA's toxic metabolic pathway.[2] Whether 6-APDB actually avoids serotonin nerve damage has never been tested. The "non-neurotoxic" claim remains a design hypothesis, not a confirmed finding.

Acute intoxication

The closest published data come from the structural analog 6-APB: a case of paranoia and psychosis was documented following recreational use combined with cannabis.[15] Most intoxication reports for the benzofuran class involve multiple substances, making it difficult to attribute specific effects to any single compound.[6]

Psychological risks

Acute psychosis has been documented for the structural analog 6-APB.[15] Compulsive redosing is commonly reported and increases acute risk through cumulative dose escalation.

The days following use typically bring depressed mood, cognitive fatigue, and irritability — consistent with serotonin depletion seen across the entactogen class.citation needed No published data address long-term psychiatric effects specific to 6-APDB.

Tolerance & dependence

No studies characterize tolerance or dependence for 6-APDB specifically. As a serotonin releaser, tolerance builds as receptors downregulate and transporters desensitize — the same process seen with MDMA.[6] Cross-tolerance with MDMA and other entactogens is expected.

Community estimates suggest tolerance takes roughly 2.5 months to fully reset.citation needed These values are unverified. 6-APDB's MDMA-like behavioral profile suggests MDMA-like abuse potential,[4] and benzofurans' greater potency than MDMA may increase reinforcement risk.[16]

2LETHAL
34DANGEROUS
22CAUTION
3UNGRADED
61 rules1 SOURCE-VERIFIED1 EDITOR-REVIEWED

6-APDB's potent serotonin-releasing activity makes it dangerous in combination with a range of common substances.

Tramadol: Classified as lethal. Tramadol inhibits serotonin reuptake while also lowering seizure threshold.[17] Combined with 6-APDB's serotonin flood, the result is extreme serotonin syndrome risk. A death from tramadol combined with multiple serotonergic drugs has been documented.[18]

MDMA: Combining two potent serotonin releasers stacks the serotonergic load, dramatically elevating risk of overheating, cardiovascular toxicity, and serotonin syndrome.[19]

MAOIs: Combining 6-APDB with monoamine oxidase inhibitors — including antidepressants like phenelzine or tranylcypromine — can produce a fatal serotonin surge. This is an absolute contraindication.

SSRIs/SNRIs: These antidepressants block the SERT through which 6-APDB releases serotonin. This creates a pharmacological conflict that may blunt effects while paradoxically elevating serotonin syndrome risk.[19]

Benzofuran compounds combined with other substances carry high risk of severe adverse effects and death.[6]

Contraindications

8 known
3ABSOLUTE
5RELATIVE

Cardiovascular conditions: Pre-existing heart valve disease or pulmonary arterial hypertension are absolute contraindications given 6-APDB's confirmed 5-HT₂B agonism.[1][14]

Psychiatric conditions: Personal or family history of psychotic disorders is a relative contraindication, supported by the 6-APB psychosis case.[15]

Concurrent medications: MAOIs, SSRIs, SNRIs, tramadol, triptans, lithium, and linezolid are contraindicated due to serotonin syndrome risk.

Liver impairment: Impaired liver function may produce elevated blood levels and prolonged effects — inferred from analogy to MDMA and 5-APB metabolism data.[12]inferred

Harm Reduction[edit]

Forms & Identification

Reagent ResultsNot recorded+ add reagent results
AppearanceNot recorded+ add appearance
Red FlagsNot recorded+ add red flags

6-APDB circulates as a white to off-white powder or pressed tablets, often without specific compound identification — historically sold as part of "benzofury" blends or as a generic MDMA replacement.

Reagent testing can confirm the presence of a benzofuran compound but cannot distinguish between positional isomers (5-APDB vs 6-APDB) or saturated vs unsaturated variants (6-APDB vs 6-APB). GC-MS or equivalent laboratory analysis is the only reliable identification method. Any substance sold as 6-APDB warrants skepticism about identity and purity.

Guidelines

  • Test substance identity before use — reagent kits at minimum, laboratory analysis if accessible
  • Start with a low dose and wait at least 90 minutes before considering redosing due to slow onset
  • Plan for 6–8 hours of effects plus comedown — ensure no time-critical obligations
  • Keep hydrated but avoid overhydration — moderate sipping rather than large volumes
  • Avoid frequent use: 5-HT₂B-mediated cardiac risk is cumulative and proportional to total exposure
  • Space sessions by at least one month to allow serotonin system recovery
  • Have a trusted person present who is aware of what was taken and approximate timing
  • Eat a light meal 2–3 hours before; an empty stomach speeds onset but a full stomach may blunt it unpredictably

Set & Setting

The slow onset — 30–60 minutes to first effects — creates a window where premature redosing is common. Users expecting MDMA-speed onset may assume the dose was insufficient and take more. Plan for 6–8 hours of effects, longer than typical MDMA use.

A calm environment with trusted company supports the empathogenic experience. The compound can amplify existing emotional states during the comedown — a settled headspace at the outset reduces the risk of difficult processing as serotonin levels drop.

Aftercare & integration. The serotonin depletion following 6-APDB use typically produces a mood dip 1–3 days after the experience. This is neurochemical, not psychological — serotonin stores take time to rebuild. Supporting recovery:

  • Prioritize sleep in the 48 hours following use
  • Eat nutrient-dense foods; tryptophan-rich foods (eggs, turkey, nuts) support serotonin synthesis
  • Avoid other serotonergic substances during the recovery window
  • Light exercise can improve mood but avoid intense physical exertion while depleted
  • If emotional insights arose during the experience, journaling within 24–48 hours helps consolidate them before they fade

If low mood persists beyond 5–7 days, or if pre-existing depression is significantly worsened, seek professional support.

Recovery & Support

Compulsive redosing and increasing frequency of use are the primary patterns of concern with entactogens. Warning signs include using more often than monthly, difficulty maintaining planned spacing, or continued use despite diminished effects or worsening comedowns.

The cumulative cardiac risk from 5-HT₂B agonism means frequency reduction has direct physical health implications — not just psychological ones. Damage may not produce symptoms until it is already significant.

Support resources include harm reduction organizations, psychedelic integration therapists, and substance use counselors familiar with entactogen patterns. MDMA-specific recovery resources are broadly applicable given the shared pharmacological class.

Recovery resources, crisis lines, and support pathways → View all

Emergency Response

Recognizing an emergency:

These signs distinguish a medical emergency from ordinary discomfort (mild jaw tension, moderate stimulation, temporary anxiety).

Immediate steps:

  • 1. Call emergency services immediately if any red flags above are present
  • 2. Move the person to a cool, quiet space
  • 3. Remove excess clothing to help cooling if overheating
  • 4. Place in recovery position if consciousness is impaired
  • 5. Do NOT restrain unless there is immediate danger of self-harm
  • 6. Do NOT give additional substances to "counteract" effects

What to tell the dispatcher:

Name the substance (6-APDB / benzofuran entactogen), approximate amount and time taken, and current symptoms. Good Samaritan laws in many jurisdictions protect people who call for help during drug emergencies.

Safety[edit]

Harm
Acute toxicity
Low
Chronic toxicity
Moderate
Withdrawal
None
Tolerance buildup
moderate
Tolerance reset
75 days
Dependence
Physical
Negligible
Psychological
Low
Compulsive redosing
Moderate
Dose escalation
Low
Cross-tol.
MDMA · MDA · 6-APB
Risk Shape
TOXPHYPSYWDRREDTOL

Toxicity

No lethal dose has been established for 6-APDB in any species, and no case reports of 6-APDB-specific overdose or fatality exist in the indexed literature.

Cardiovascular toxicity

6-APDB is a confirmed serotonin₂B receptor agonist.[1] Chronic activation of this receptor causes heart valve fibrosis and pulmonary arterial hypertension — the same mechanism that led to fenfluramine's withdrawal from the market.[4][12] This risk applies specifically to repeated or frequent use and is not shared with MDMA. The cumulative exposure threshold required to produce detectable valve damage from benzofuran entactogens is unknown.

The mechanism involves activation of growth-promoting signaling in valve tissue cells, leading to fibrotic thickening.[15] 5-HT₂B agonism remains a critical safety liability in pharmaceutical development.[16]

Serotonin toxicity

As a potent serotonin releaser, 6-APDB carries significant risk of serotonin syndrome when combined with other serotonergic agents. Features include agitation, involuntary muscle jerking, overheating, rapid heart rate, and tremor. Life-threatening complications include body temperature exceeding 41°C, muscle breakdown, and organ failure.safety citation needed

Neurotoxicity

The original synthesis aimed to produce non-neurotoxic entactogens by modifying the methylenedioxy ring oxygens implicated in MDA/MDMA's toxic metabolic pathway.[2] No studies have directly tested whether 6-APDB actually avoids serotonergic terminal damage. The "non-neurotoxic" framing remains a design hypothesis, not a confirmed finding.

Acute intoxication

The closest published clinical data come from the structural analog 6-APB: a case of acute psychosis with agitation and paranoia was documented following recreational use combined with cannabis.[17] Intoxication reports for the benzofuran class consistently involve multiple substances, complicating attribution of specific effects to individual compounds.[5]

Psychological risks

Acute psychosis has been documented for the structural analog 6-APB.[17] Compulsive redosing is reported as a feature of 6-APDB use, increasing acute toxicity risk through cumulative dose escalation.

Comedown effects include depressed mood, cognitive fatigue, and irritability — consistent with post-release serotonin depletion observed across the entactogen class.citation needed No published data address long-term psychiatric effects specific to 6-APDB.

Tolerance & dependence

No published studies characterize tolerance or dependence for 6-APDB specifically. As a serotonin releasing agent, tolerance develops through downregulation and transporter desensitization following repeated exposure — the same mechanism observed with MDMA.[5] Cross-tolerance with MDMA and other entactogens is expected.

Community estimates suggest tolerance half-life of approximately 25 days and full reset at 2.5 months.citation needed These values are unverified.

6-APDB's MDMA-like discriminative stimulus profile suggests MDMA-like abuse potential.[3] Benzofurans' greater potency than MDMA may increase risk for reinforcement-related adverse outcomes.[18]

2LETHAL
34DANGEROUS
22CAUTION
3UNGRADED
61 rules1 SOURCE-VERIFIED1 EDITOR-REVIEWED

The most critical interactions arise from 6-APDB's potent serotonin-releasing activity.

Tramadol: Classified as lethal. Tramadol inhibits the SERT in addition to its opioid effects.[19] Combined with 6-APDB's serotonin release, this creates extreme serotonin syndrome risk. Tramadol also lowers seizure threshold independently. A death from tramadol combined with multiple serotonergic drugs has been documented.[20]

MDMA: Combining two potent serotonin releasers creates stacked serotonergic load with dramatically elevated risk of serotonin syndrome, overheating, and cardiovascular toxicity.[21]

MAOIs: Combination with monoamine oxidase inhibitors — irreversible (phenelzine, tranylcypromine) or reversible (moclobemide) — produces extreme serotonin elevation with potentially fatal outcome. This is an absolute contraindication.

SSRIs/SNRIs: SSRIs block the serotonin transporter through which 6-APDB releases serotonin, creating a pharmacological conflict that may both blunt effects and paradoxically elevate serotonin syndrome risk.[21]

Intoxication reports for benzofuran compounds consistently involve multiple substances, with high risk of severe adverse effects and death.[5]

Contraindications

8 known
3ABSOLUTE
5RELATIVE

Cardiovascular conditions: Pre-existing heart valve disease and pulmonary arterial hypertension are absolute contraindications given 6-APDB's confirmed 5-HT₂B agonism.[1] The compound adds direct pharmacological insult to structurally compromised valve tissue.[15]

Psychiatric conditions: Personal or family history of psychotic disorders is a relative contraindication, supported by the 6-APB psychosis case.[17]

Concurrent medications: MAOIs, SSRIs, SNRIs, tramadol, triptans, lithium, and linezolid are contraindicated due to serotonin syndrome risk.

Liver impairment: If 6-APDB is metabolized through liver enzymes — inferred from analogy to MDMA and 5-APB data[13] — impaired liver function could produce elevated blood levels and prolonged effects.inferred

Harm Reduction[edit]

Forms & Identification

Reagent ResultsNot recorded+ add reagent results
AppearanceNot recorded+ add appearance
Red FlagsNot recorded+ add red flags

6-APDB circulates primarily as a white to off-white powder or pressed tablets, often without specific compound identification — it was historically sold as part of "benzofury" blends or generic MDMA replacements. The critical testing concern is distinguishing 6-APDB from its unsaturated structural analog 6-APB and from substances with substantially different dose ranges.

Reagent testing can confirm the presence of a benzofuran compound but cannot reliably distinguish between positional isomers (5-APDB vs 6-APDB) or saturated vs unsaturated variants (6-APDB vs 6-APB). Quantitative analysis (GC-MS or similar) is the only reliable identification method. Given the compound's rarity in current markets, any substance sold as 6-APDB warrants particular skepticism about identity and purity.

Guidelines

  • Test substance identity before use — reagent kits at minimum, laboratory analysis if accessible
  • Start with a low dose and wait at least 90 minutes before considering redosing due to slow onset
  • Plan for 6–8 hours of effects plus comedown — ensure no time-critical obligations
  • Keep hydrated but avoid overhydration — moderate sipping rather than large volumes
  • Avoid frequent use: 5-HT₂B-mediated cardiac risk is cumulative and proportional to total exposure
  • Space sessions by at least one month to allow serotonin system recovery
  • Have a trusted person present who is aware of what was taken and approximate timing
  • Eat a light meal 2–3 hours before; an empty stomach speeds onset but a full stomach may blunt it unpredictably

Set & Setting

The slow onset (30–60 minutes to first effects) creates a window where premature redosing is common — users expecting MDMA-speed onset may assume the dose was insufficient. The extended duration (6–8 hours) means planning for a longer session than typical MDMA use.

A calm, comfortable environment with trusted company supports the entactogenic experience. The compound's empathogenic character responds well to social settings but can amplify existing emotional states during the comedown phase — having a settled, positive headspace at the outset reduces the risk of difficult emotional processing as serotonin levels drop.

Aftercare & integration. The serotonin depletion following 6-APDB use typically produces a mood dip 1–3 days after the experience. This is neurochemical, not psychological — serotonin stores take time to rebuild. Supporting recovery:

  • Prioritize sleep in the 48 hours following use
  • Eat nutrient-dense foods; tryptophan-rich foods (eggs, turkey, nuts) support serotonin synthesis
  • Avoid other serotonergic substances during the recovery window
  • Light exercise can improve mood but avoid intense physical exertion while depleted
  • If emotional insights arose during the experience, journaling within 24–48 hours helps consolidate them before they fade

If low mood persists beyond 5–7 days, or if pre-existing depression is significantly worsened, seek professional support.

Recovery & Support

Compulsive redosing and increasing frequency of use are the primary patterns of concern with entactogens. Warning signs include using more often than monthly, difficulty maintaining planned spacing between sessions, or continued use despite noticing diminished effects (tolerance) or worsening comedowns.

The cumulative cardiac risk from 5-HT₂B agonism means that frequency reduction is not just about psychological wellbeing — it carries direct physical health implications that may not produce symptoms until significant damage has occurred.

Support resources include harm reduction organizations, psychedelic integration therapists, and substance use counselors familiar with entactogen patterns. MDMA-specific recovery resources are broadly applicable given the shared pharmacological class.

Recovery resources, crisis lines, and support pathways → View all

Emergency Response

Recognizing an emergency:

These signs distinguish a medical emergency from ordinary discomfort (mild jaw tension, moderate stimulation, temporary anxiety).

Immediate steps:

  • 1. Call emergency services immediately if any red flags above are present
  • 2. Move the person to a cool, quiet space
  • 3. Remove excess clothing to help cooling if overheating
  • 4. Place in recovery position if consciousness is impaired
  • 5. Do NOT restrain unless there is immediate danger of self-harm
  • 6. Do NOT give additional substances to "counteract" effects

What to tell the dispatcher:

Name the substance (6-APDB / benzofuran entactogen), approximate amount and time taken, and current symptoms. Good Samaritan laws in many jurisdictions protect people who call for help during drug emergencies.

Frequently asked questions

What is 6-APDB?

6-APDB is a synthetic entactogen and stimulant of the substituted benzofuran class, first synthesized at Purdue University in 1993. It acts as a preferentially serotonergic triple monoamine releasing agent distinguished from MDMA by confirmed 5-HT₂B receptor agonism.

How long does 6-APDB last?

Total duration by route of administration — Oral: 6 – 8 hours. Ranges vary with dose and individual factors; see the duration table for onset, peak, and after-effect phases.

Where can I find dosage information for 6-APDB?

Psychedex publishes a dosage table for 6-APDB on this page covering these routes of administration: oral. Dose values are presented only in that table, always alongside their route of administration.

What are dangerous combinations with 6-APDB?

The highest-severity documented interactions for 6-APDB: MAOIs (Lethal), 5-HTP, Tryptophan (Dangerous), Alpha-2 adrenergic receptor antagonist (Dangerous), Anticholinergics (Dangerous), Antihistamines (Dangerous). See the interactions section for the full list with mechanisms and severity levels.

Is 6-APDB addictive?

Psychedex records tolerance and dependence data rather than a yes/no rating. Recorded tolerance indicators for 6-APDB: tolerance builds moderate; full reset takes 75 days; cross-tolerance develops with MDMA, MDA, 6-APB, 5-APB, 5-APDB, methylone. See the article's dependence and safety sections for recorded dependence data.

experience reports

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First-person accounts of subjective effects, timing, and outcomes — submitted for harm reduction.

references

  1. [1] 
    ^abcdefgRickli A, Kopf S, Hoener MC, Liechti ME (2015) Pharmacological profile of novel psychoactive benzofurans — British Journal of Pharmacology doi:10.1111/bph.13128
  2. [2] 
    ^abcdefgMonte AP, Marona-Lewicka D, Cozzi NV, Nichols DE (1993) Synthesis and pharmacological examination of benzofuran, indan, and tetralin analogues of 3,4-(methylenedioxy)amphetamine — Journal of Medicinal Chemistry doi:10.1021/jm00075a027
  3. [3] 
    ^abSchifano F, Vento A, Scherbaum N, Guirguis A (2023) Stimulant and hallucinogenic novel psychoactive substances; an update — Expert Review of Clinical Pharmacology doi:10.1080/17512433.2023.2279192
  4. [4] 
    ^abcdefDolan SB, Forster MJ, Gatch MB (2017) Discriminative stimulus and locomotor effects of para-substituted and benzofuran analogs of amphetamine — Drug and Alcohol Dependence doi:10.1016/j.drugalcdep.2017.07.041
  5. [5] 
    ^abcRothman RB, Baumann MH (2009) Serotonergic drugs and valvular heart disease — Expert Opinion on Drug Safety doi:10.1517/14740330902931524
  6. [6] 
    ^abcdeLuethi D, Liechti ME (2020) Designer drugs: mechanism of action and adverse effects — Archives of Toxicology doi:10.1007/s00204-020-02693-7

references

  1. [1] 
    ^abcdefghijRickli A, Kopf S, Hoener MC, Liechti ME (2015) Pharmacological profile of novel psychoactive benzofurans — British Journal of Pharmacology doi:10.1111/bph.13128
  2. [2] 
    ^abcdefghMonte AP, Marona-Lewicka D, Cozzi NV, Nichols DE (1993) Synthesis and pharmacological examination of benzofuran, indan, and tetralin analogues of 3,4-(methylenedioxy)amphetamine — Journal of Medicinal Chemistry doi:10.1021/jm00075a027
  3. [3] 
    ^abcdefgDolan SB, Forster MJ, Gatch MB (2017) Discriminative stimulus and locomotor effects of para-substituted and benzofuran analogs of amphetamine — Drug and Alcohol Dependence doi:10.1016/j.drugalcdep.2017.07.041
  4. [4] 
    ^abcRothman RB, Baumann MH (2009) Serotonergic drugs and valvular heart disease — Expert Opinion on Drug Safety doi:10.1517/14740330902931524
  5. [5] 
    ^abcdLuethi D, Liechti ME (2020) Designer drugs: mechanism of action and adverse effects — Archives of Toxicology doi:10.1007/s00204-020-02693-7
  6. [6] 
    ^Schifano F, Vento A, Scherbaum N, Guirguis A (2023) Stimulant and hallucinogenic novel psychoactive substances; an update — Expert Review of Clinical Pharmacology doi:10.1080/17512433.2023.2279192
Last updated Jun 4, 2026