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2C-H

2,5-dimethoxyphenethylamine

Overview

2C-H (2,5-dimethoxyphenethylamine) is a synthetic psychedelic of the phenethylamine class. It is the parent scaffold of the 2C series — the blank structural template from which active derivatives like 2C-B are built. It binds serotonin receptors too weakly to produce psychoactive effects at any practical oral dose.[1][2]

2C-H (2,5-dimethoxyphenethylamine) is a synthetic psychedelic of the phenethylamine class. It is the unsubstituted parent scaffold of the 2C series, from which potent derivatives like 2C-B are built. 2C-H is a weak partial agonist at 5-HT₂A receptors, with binding affinity too low to produce meaningful psychoactive effects.[1][2]

Entity
2C-H
PSX-0032
2C-H 2D chemical structure
Open Beta

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NoticeAll →
•1 lethal interaction(all →)
Common names2C-H, DMPEA
Substitutive name2,5-dimethoxyphenethylamine
— no data —
Builduprapid
Full reset8.5 days
Cross-tol.psychedelic 5-HT₂A agonists
Absolute2 entries
Concurrent MAOI useConcurrent tramadol use
Relative4 entries
Cardiovascular diseaseSeizure disordersSevere psychiatric disordersPrior serotonin toxicity
Dosage varies by body weight, tolerance & metabolism · Not medical advice · Terms
See an error? Suggest correction
See an error? Suggest correction

Johannes Buck synthesized 2C-H in 1932 while mapping mescaline analogues.[3] Alexander Shulgin documented it in 1991 as the structural launchpad for the 2C family, calling it "probably inactive" due to enzymatic breakdown.[2] In 2021, researchers identified 2C-H's core structure as the minimal scaffold needed for anti-inflammatory activity among serotonin-receptor agonists.[4]

Subjective effects include none that have been confirmed — no human trial has characterized 2C-H by any route.[2] If non-oral delivery achieved brain concentrations, its preference for calming serotonin signaling over psychedelic serotonin signaling suggests a qualitatively different profile from typical 2C compounds.[1] Oral activity is blocked by rapid enzymatic breakdown before the compound can reach the bloodstream.[5]

2C-H is not expected to produce physical dependence, and no toxic dose specific to it has been documented.[6] Its main risk is potent inhibition of MAO-B — the enzyme that clears dopamine and related chemicals — creating dangerous interaction potential with serotonergic or dopaminergic substances.[5] Nearly every pharmacological parameter is uncharacterized; current understanding rests on lab data and structural analogy, not human studies.

History[edit]

Discovery

2C-H was first synthesized in 1932 by Johannes Buck, working through a systematic study of mescaline analogues.[3] He established the basic synthetic route but did not investigate whether the compound had psychoactive properties.

The 2C series and Shulgin's legacy

Alexander Shulgin documented 2C-H as Compound #32 in 1991's PiHKAL.[2] He listed dose and duration as "unknown," called it "probably inactive," and recognized it as "one of the most magnificent launching pads" for the 2C family — 2C-B, 2C-I, 2C-E, and the rest.

Scheduling and modern research

2C-H was scheduled in the United States in 2012 and Canada in 2016 — both actions targeting the 2C structural class broadly, not 2C-H specifically.[7] In 2021, Flanagan et al. showed that 2C-H's core structure is the minimal scaffold needed for anti-inflammatory activity among serotonin-receptor agonists[4] — the first published research establishing a role for 2C-H beyond its status as a synthetic intermediate.

Chemistry[edit]

Structural class

2C-H belongs to the substituted phenethylamine family and is the parent compound of the 2C series. Its molecular formula is C₁₀H₁₅NO₂ (molecular weight 181.23 g/mol). The 4-position of its phenyl ring — the site that determines psychedelic potency across the 2C series — carries no substituent, making it the weakest member of the family.

Molecular formulaC₁₀H₁₅NO₂
Molecular weight181.23 g/mol

Structure-activity relationships

The two methoxy groups at positions 2 and 5 are the structural scaffold shared by every 2C compound.[9] Adding a substituent at position 4 — bromine to make 2C-B, iodine to make 2C-I — converts this inactive template into a potent psychedelic. 2C-H's empty 4-position is why it is pharmacologically the weakest of its class.[9]

Pharmacology[edit]

Mechanism of action

2C-H acts on serotonin receptors, but 30 to 80 times more weakly than active 2C compounds like 2C-B and 2C-I.[1][9] Unusually, it shows the strongest preference in its class for calming serotonin signaling over psychedelic serotonin signaling.[1]

MAO-B inhibition

2C-H is the most potent MAO-B inhibitor among tested 2C compounds, with an IC₅₀ of 1.7 µM.[5] The enzyme MAO-B normally destroys 2C-H in the gut before it reaches the bloodstream — explaining its oral inactivity. Via non-oral routes, systemic 2C-H could dangerously elevate dopamine and related chemicals, creating interaction risks not typical of other 2C compounds.[5]

Anti-inflammatory pharmacophore

In 2021, Flanagan et al. identified 2C-H's core scaffold as the minimal structural unit needed for anti-inflammatory activity among serotonin-receptor agonists.[4] This anti-inflammatory effect operates through a separate signaling pathway from psychedelic activity,[4] confirmed in 2024.[10] No human pharmacokinetic data exist; key parameters — half-life, peak plasma time, protein binding — are entirely uncharacterized.[5][11]

2C-H is classified as a "psychedelic" based on its structural membership in the 2C phenethylamine family, not on demonstrated psychoactive properties. It is the parent scaffold from which psychedelic 2C compounds are derived, but is not itself established to produce psychedelic effects.

Neuroscience[edit]

Where it acts

No neuroimaging or brain-activity data specific to 2C-H exist. Based on class pharmacology, 2C compounds produce psychedelic effects through serotonin receptor activation in the prefrontal cortex — disrupting how the brain filters sensory information and destabilizing the default mode network.[6][12] Whether 2C-H can achieve sufficient receptor activation to trigger these changes at any dose or route is unknown.

2C-H's unusually strong preference for calming serotonin receptors suggests that if it reached the brain via a non-oral route, the experience might be more sedating than perceptual — qualitatively different from typical 2C psychedelics.[1]

Why it matters

2C-H illustrates biased agonism — the principle that different molecules binding the same receptor can activate completely different downstream responses.[4][13] Its anti-inflammatory activity separates cleanly from psychedelic activity, raising the possibility of designing derivatives that treat inflammation without producing psychedelic effects.

Subjective Effects[edit]

Summary

2C-H has no established subjective effect profile. It is considered orally inactive — monoamine oxidase destroys it before it reaches the bloodstream. Effect data sometimes attributed to it are extrapolated from the broader 2C class, not from evidence specific to 2C-H. It sits at the pharmacologically inactive extreme of a family that includes potent psychedelics.

By comparison, 2C-B and 2C-I produce robust perceptual effects at standard oral doses. 2C-H combines the weakest serotonin receptor binding in its class with the highest vulnerability to enzymatic breakdown — placing it closer to inert trace amines than to the recreational psychedelics it structurally resembles.

First synthesized in 1932 by Johannes Buck as part of a systematic exploration of mescaline analogues, 2C-H sat unexamined for decades.[3] Alexander Shulgin's 1991 PiHKAL described it as "probably inactive" yet celebrated it as the structural launchpad from which the pharmacologically active 2C family — 2C-B, 2C-I, 2C-E — was built.[2] In 2021, 2C-H gained independent research significance when it was identified as the minimal anti-inflammatory pharmacophore for 5-HT₂A receptor agonists.[4]

Subjective effects have not been established — no controlled human trial has characterized 2C-H's experiential properties by any route.[2] If psychoactive concentrations were achieved via non-oral routes, the compound's unusual receptor profile — strong 5-HT₁A preference over 5-HT₂A — would predict an experience qualitatively different from typical 2C psychedelics.[1] Rapid enzymatic breakdown by monoamine oxidase is the primary barrier to oral activity.[5]

2C-H is not expected to produce physical dependence, and no toxic dose or adverse event specific to the compound has been documented.[6] The primary pharmacological risk is its potent MAO-B inhibition, which could produce dangerous monoamine interactions if combined with serotonergic or dopaminergic substances.[5] Nearly every pharmacological parameter remains uncharacterized — the current understanding rests on in vitro data, structural analogy, and Shulgin's original assessment.

History[edit]

Discovery

2C-H was first synthesized in 1932 by Johannes Buck at Burroughs Wellcome as part of a systematic study of mescaline analogues.[3] The compound retained methoxy groups at the 2- and 5-positions of the phenyl ring while eliminating the substitution pattern that gives mescaline its psychoactive potency. Buck established the basic synthetic route from 2,5-dimethoxybenzaldehyde but did not investigate the compound's psychopharmacology.

The 2C series and Shulgin's legacy

2C-H received its most significant documentation as Compound #32 in Alexander and Ann Shulgin's 1991 PiHKAL.[2] Shulgin listed both dose and duration as "unknown" and described the compound as "probably inactive," yet recognized its structural importance — calling it "one of the most magnificent launching pads" for the substituted 2C compounds. His observation that "the 4-position is where the action is" framed 2C-H as the blank canvas from which 2C-B, 2C-I, 2C-E, and the rest of the series were derived.

Scheduling and modern research

2C-H was classified as Schedule I in the United States under the Synthetic Drug Abuse Prevention Act of 2012, and as Schedule III in Canada in 2016 — both actions targeting the 2C structural class broadly rather than 2C-H based on individual evidence of abuse.[7] The compound's independent pharmacological significance emerged in 2021, when Flanagan et al. identified the 2,5-dimethoxyphenethylamine scaffold as the minimal anti-inflammatory pharmacophore for 5-HT₂A receptor agonists in a rat model of allergic asthma[4] — the first published study to establish a role for 2C-H beyond its status as a synthetic intermediate.

Chemistry[edit]

Structural class

2C-H belongs to the substituted phenethylamine family and is the parent compound of the 2C series. Its IUPAC name is 2-(2,5-dimethoxyphenyl)ethanamine. The molecule consists of a phenyl ring bearing methoxy groups at positions 2 and 5, connected to a two-carbon ethylamine chain. The 4-position — the site that determines psychedelic potency across the 2C family — carries no substituent, which accounts for the compound's pharmacological weakness relative to derivatives like 2C-B (4-bromo) and 2C-I (4-iodo).

Molecular formulaC₁₀H₁₅NO₂
Molecular weight181.23 g/mol

Structure-activity relationships

The 2,5-dimethoxy motif is the pharmacologically necessary scaffold for all 2C compounds. Removal of either methoxy group modestly reduces receptor affinity in vitro but dramatically attenuates psychedelic activity in animal models, confirming that both groups contribute to receptor engagement geometry.[9] Potency across the series is driven primarily by the 4-position substituent — its steric bulk, electronic character, and lipophilicity determine binding strength at the 5-HT₂A receptor.

2C-H's empty 4-position makes it the weakest member of its family.

Stereochemistry and physical properties

2C-H is achiral — the ethylamine side chain carries no α-carbon substitution, unlike the amphetamine-derived DOx series where an α-methyl group creates distinct enantiomers. The free base is a colorless, viscous liquid that absorbs atmospheric carbon dioxide readily.[1] The hydrochloride salt melts at 138–139°C.[1]

No published solubility or stability data exist for either form.

Pharmacology[edit]

Mechanism of action

2C-H acts as a weak partial agonist at serotonin 5-HT₂A and 5-HT₂C receptors.[1] Its binding strength at 5-HT₂A is roughly 30- to 80-fold weaker than pharmacologically active 2C compounds such as 2C-B and 2C-I.[1][9] This weakness is consistent with the established principle that 4-position substitution drives potency in the 2C series — 2C-H has none.[9]

An unusual feature is 2C-H's relatively strong affinity for the 5-HT₁A receptor — the highest in the 2C series.[1] The selectivity ratio (approximately 23:1 for 5-HT₁A over 5-HT₂A) would predict calming or modulatory effects rather than psychedelic activity, if the compound reached the brain in sufficient concentration.

MAO-B inhibition

2C-H is the most potent MAO-B inhibitor among tested 2C compounds, with an IC₅₀ of 1.7 µM.[5] No significant MAO-A inhibition was detected.[5]

This selective MAO-B activity has two consequences: it explains 2C-H's oral inactivity — the unsubstituted 4-position leaves the terminal amine fully exposed to rapid enzymatic breakdown in the gut and liver before the compound can reach the bloodstream — and it introduces pharmacologically relevant monoamine interactions if the compound bypasses first-pass metabolism via non-oral routes.[5]

Anti-inflammatory pharmacophore

Flanagan et al. (2021) identified 2C-H as the minimal structural unit necessary for anti-inflammatory activity among 5-HT₂A agonists, using a rat model of allergic asthma.[4] The anti-inflammatory effects showed no correlation with the calcium signaling pathway or behavioral psychedelic potency, demonstrating that the anti-inflammatory and psychoactive properties of 5-HT₂A agonists operate through separable signaling mechanisms.[4]

A 2024 follow-up confirmed this functional selectivity by showing that structurally similar agonists produce divergent anti-inflammatory outcomes despite comparable receptor activation.[10]

Psychoactivity

No published human trials of 2C-H exist. Shulgin described both dose and duration as "unknown" in PiHKAL, annotating that the compound is "probably inactive" due to monoamine oxidase degradation.[2] The mechanistic basis is now confirmed: rapid MAO-B-mediated breakdown would prevent meaningful absorption via the oral route,[5] and the weak 5-HT₂A binding means that even if some compound reached the brain, receptor occupancy at any practical dose would be negligible.[1]

2C-H is classified as a "psychedelic" based on its structural membership in the 2C phenethylamine family, not on demonstrated psychoactive properties. It is the parent scaffold from which psychedelic 2C compounds are derived, but is not itself established to produce psychedelic effects.

Pharmacokinetics

No human pharmacokinetic data for 2C-H have been published. Oral bioavailability is expected to be very low due to extensive first-pass MAO-B metabolism.[5] Non-oral routes (intranasal, intravenous) would bypass this degradation but have not been studied in humans.

The 2C series as a class undergoes liver metabolism primarily through O-demethylation and N-acetylation.[11] No metabolite studies specific to 2C-H exist. Key parameters — peak plasma time, half-life, and protein binding — remain entirely uncharacterized.

Neuroscience[edit]

Where it acts

No neuroimaging or electrophysiology data specific to 2C-H exist. Based on class pharmacology, 2C compounds produce psychedelic effects through 5-HT₂A activation on layer V neurons in the prefrontal cortex, disrupting the brain's normal filtering of sensory and cognitive information and destabilizing the default mode network.[6][12] Whether 2C-H can achieve sufficient receptor occupancy to trigger these network-level changes at any dose or route remains unknown.

2C-H's unusual 5-HT₁A preference introduces a theoretical wrinkle: if it reached the brain via a non-oral route, its pharmacological signature might favor 5-HT₁A-mediated calming over 5-HT₂A-mediated perceptual disruption — a qualitatively different profile from typical 2C psychedelics.[1]

Why it matters

2C-H exemplifies biased agonism at the 5-HT₂A receptor — the principle that different agonists stabilize different receptor conformations, activating distinct downstream signaling cascades.[4][13] Its anti-inflammatory activity dissociates cleanly from both the calcium signaling pathway and psychedelic behavioral output, suggesting the 2,5-dimethoxyphenethylamine scaffold preferentially engages an anti-inflammatory conformation while inadequately activating the one responsible for psychedelic effects.

If these pathways can be structurally dissected, 2C-H derivatives could yield non-psychedelic anti-inflammatory therapeutics — a direct translational application of the biased agonism framework.

Subjective Effects[edit]

Summary

2C-H has no established subjective effect profile. Shulgin described it as "probably inactive" via the oral route, and no controlled human study has characterized its experiential properties by any route. Effect data sometimes attributed to 2C-H — color enhancement, stimulation, cognitive euphoria — are extrapolated from the broader 2C class and do not reflect substance-specific evidence. If psychoactive concentrations were achieved through non-oral routes, the compound's strong 5-HT₁A preference over 5-HT₂A would predict a qualitatively different experience from typical 2C psychedelics.

2C-H occupies the inactive extreme of the 2C series — the pharmacological inverse of 2C-B or 2C-I, which produce robust psychedelic effects at oral doses of 10–25 mg. Where those compounds demonstrate strong serotonin receptor binding and resist enzymatic breakdown, 2C-H combines the weakest receptor affinity in its class with the highest vulnerability to MAO-B degradation, placing it closer to endogenous trace amines than to recreational psychedelics.

Effect Grid

Dose Level:
Description

No common dose range has been established for 2C-H. Unlike its derivatives 2C-B (common dose 15–25 mg oral) and 2C-I (common dose 14–22 mg oral), 2C-H lacks the 4-position substituent that confers both receptor potency and metabolic stability to the 2C series.

The concept of a "common dose" is not applicable to a compound with no established psychoactivity. All subjective effect data conventionally associated with 2C-H are extrapolated from active 2C-class members and do not reflect substance-specific evidence.

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

Perception(2)likelihood · intensity
Color enhancement
rare
Music enhancement
rare
Body(14)likelihood · intensity
Stimulation
possible
Pupil dilation
possible
Dry mouth
possible
Restlessness
possible
Wakefulness
possible
Abnormal heartbeat!
rare
Temperature dysregulation!
rare
Excessive sweating
rare
Vasoconstriction!
rare

Restlessness · Wakefulness · Excessive sweating · Appetite suppression · Heart rate perception changes · Muscle tension · Nausea · Vasoconstriction · Spontaneous body sensations

Appetite suppression · Heart rate perception changes · Muscle tension · Nausea · Spontaneous body sensations

Thinking(2)likelihood · intensity
Cognitive euphoria
rare
Humor enhancement
rare
Feeling(3)likelihood · intensity
Anxiety
rare
Euphoria
rare
Paranoia!
rare
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
Negligible
Chronic toxicity
No data
Withdrawal
None
Tolerance buildup
rapid
Tolerance reset
8.5 days
Dependence
Physical
None
Psychological
None
Compulsive redosing
Negligible
Dose escalation
Negligible
Cross-tol.
psychedelic 5-HT₂A agonists
Risk Shape
TOXPHYPSYWDRREDTOL

Toxicity

No LD₅₀ data, toxicity studies, or adverse event case reports specific to 2C-H exist.[6] The toxic dose is unknown. Its weak serotonin receptor binding and probable oral inactivity suggest lower acute toxicity than active 2C compounds, but this has not been verified.

Class-level toxicity

For the 2C series as a class, toxic effects include agitation, elevated blood pressure, rapid heart rate, seizures, dangerously elevated body temperature, and a potentially life-threatening serotonin overload response.[6] At least five deaths have been attributed to active 2C-series members (2C-E, 2C-I, 2C-B) — none involving 2C-H specifically.[6]

MAO-B-related toxicity

2C-H's potent MAO-B inhibition introduces a toxicity risk independent of its serotonin activity.[5] Via non-oral routes that bypass gut metabolism, it could elevate dopamine and phenethylamine levels — creating dangerous interaction potential not typical of other 2C compounds.

Neurotoxicity

Cell studies on related 2C-T compounds have observed mitochondrial damage and oxidative stress.[14] Whether the 2C-H scaffold contributes to this independently, or whether substituents unique to 2C-T compounds drive the effect, is unknown.

Psychological risks

No psychological adverse events specific to 2C-H have been documented. At oral doses, the compound's probable inactivity makes acute psychological risks unlikely. If psychoactive concentrations were achieved via non-oral routes, class-level risks — anxiety, panic, hallucinations, and persistent perceptual disturbances — would theoretically apply, but no data characterize this scenario.inferred

Tolerance and dependence

No substance-specific tolerance or dependence data exist. Serotonin-activating psychedelics as a class produce rapid tolerance within 24 hours of a single dose,[15] with cross-tolerance between psychedelic compounds but not with non-psychedelic ones.[15]

Tolerance parameters sometimes attributed to 2C-H — rapid buildup, approximately four-day half-life, full reset in about eight days, cross-tolerance with other psychedelics — are entirely class-extrapolated values. If 2C-H does not achieve meaningful receptor activation at any practical dose, these parameters are pharmacologically irrelevant.

2C-H is not expected to be habit-forming.[6] No reinforcement, compulsive redosing, or withdrawal has been reported or would be predicted.

1LETHAL
18DANGEROUS
37CAUTION
5UNGRADED
61 rules0 SOURCE-VERIFIED2 EDITOR-REVIEWED

2C-H's interaction profile is shaped by its dual pharmacology: weak serotonin receptor activation combined with potent MAO-B inhibition. This combination creates interaction risks distinct from those of other 2C compounds.

Tramadol

The combination with tramadol is classified as dangerous. Tramadol raises serotonin levels by blocking its reuptake and stimulating its release.[16][17] 2C-H compounds this risk through its own serotonin activity and potent MAO-B inhibition[5] — a combination specifically identified as contraindicated in pain management literature due to serotonin syndrome risk.[16]

safety citation needed No published case reports document the specific 2C-H + tramadol combination. The dangerous classification derives from mechanistic reasoning.

MAO inhibitors

2C-H's own MAO-B inhibitory activity could amplify the effect of external monoamine oxidase inhibitors, causing dangerously elevated monoamine levels.[5] A second risk: MAO inhibitors could prevent the first-pass breakdown that normally renders 2C-H orally inactive — potentially converting an assumed-inert dose into a psychoactive one.safety citation needed

Cannabis

No published data on the 2C-H–cannabis interaction exist. The interaction is classified as unknown.

Stimulants

A class-level concern exists for cardiovascular strain and serotonin amplification between 2C compounds and stimulants. 2C-H's MAO-B inhibition could theoretically slow dopamine breakdown and potentiate stimulant effects, but this has not been studied.inferred

Contraindications

6 known
2ABSOLUTE
4RELATIVE

No substance-specific contraindication data for 2C-H exist. The following are inferred from the compound's pharmacological profile and class membership.inferred

  • Concurrent MAO inhibitor use (absolute): 2C-H's own MAO-B activity creates risk of additive monoamine oxidase inhibition and potential serotonin syndrome.
  • Concurrent tramadol use (absolute): dual serotonergic mechanism creates serotonin syndrome risk identified as contraindicated in clinical literature.
  • History of serotonin syndrome (relative): any serotonergic compound may lower the threshold for recurrence.
  • Heart conditions (relative, class-extrapolated): 2C compounds can cause elevated blood pressure and rapid heart rate, though 2C-H's weak activity makes this unlikely at oral doses.
  • Seizure disorders (relative, class-extrapolated): 2C compounds have been associated with seizures in acute toxicity; relevance to 2C-H is unclear.
  • Severe psychiatric disorders (relative, class-extrapolated): psychotic spectrum disorders and conditions worsened by serotonergic perturbation are standard contraindications for the 2C class.

Harm Reduction[edit]

Forms & Identification

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

2C-H appears almost exclusively in laboratory and research chemical contexts. It has no established recreational use and no recognized active dose. The primary identification risk is confusion with pharmacologically active 2C-series compounds — material sold as 2C-H could be mislabeled and deliver a potent psychedelic at a dose assumed to be inert.

Reagent testing cannot reliably distinguish 2C-H from all 2C-series members. Any material obtained outside a regulated laboratory supply should be treated as unverified.

Guidelines

  • Test all material. Reagent kits and, ideally, laboratory analysis (FTIR or GC-MS through drug checking services) are the only way to verify identity and rule out contamination with active 2C analogues.
  • Do not assume inactivity. While 2C-H is considered orally inactive, material sold under this name may not be 2C-H. Treat any unverified powder as potentially active.
  • Avoid combining with MAO inhibitors. 2C-H's potent MAO-B inhibition means co-administration with MAOIs could produce unpredictable monoamine elevation or even activate the compound itself.
  • Start with the smallest possible amount if self-administration is undertaken despite the absence of established dosing. No safe dose has been determined.
  • Have a sober companion present for any exposure scenario involving an uncharacterized substance.

Set & Setting

Because 2C-H has no established psychoactive dose or confirmed effects, conventional set-and-setting guidance does not apply in the usual sense. If exposure occurs — intentional or through mislabeled material — a calm, familiar environment with a sober companion reduces risk from unexpected effects.

Aftercare & integration. If unexpected psychoactive effects occur following exposure to material labeled as 2C-H, standard psychedelic aftercare applies. Rest, hydration, and light nutrition support physical recovery. A quiet environment without demanding tasks or social obligations is appropriate for 24–48 hours following any psychoactive experience.

If distressing psychological effects persist beyond 48 hours — anxiety, perceptual disturbances, depersonalization — professional consultation is warranted. Journaling the timeline of effects, including onset, peak, and resolution, provides useful information for any future clinical encounter.

Recovery & Support

2C-H is not expected to produce dependence or compulsive use patterns. If problematic use of 2C-series compounds or research chemicals more broadly is a concern, the following resources offer support:

  • SAMHSA National Helpline (US): 1-800-662-4357 — free, confidential, 24/7 referral service
  • Talk to Frank (UK): 0300 123 6600
  • Global Drug Survey — anonymous self-assessment tools for substance use patterns
  • Local harm reduction organizations often provide non-judgmental support and referrals regardless of the specific substance involved

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

Emergency Response

Because 2C-H has no established effect profile, any unexpected reaction after ingestion of material believed to be 2C-H should be treated as a potential medical emergency — the substance may be mislabeled.

Recognizing an emergency:

Immediate steps:

  • Call emergency services immediately if any of the above are present.
  • Place an unconscious person in the recovery position (on their side, airway clear).
  • Do not induce vomiting.
  • Do not restrain a conscious person unless they are in immediate physical danger.
  • Keep the environment quiet and reduce stimulation.

What to tell the dispatcher:

  • What was taken (or what it was sold as), how much, and when
  • Current symptoms
  • Any other substances consumed
  • Good Samaritan laws in many jurisdictions protect callers from prosecution for drug-related offenses

Safety[edit]

Harm
Acute toxicity
Negligible
Chronic toxicity
No data
Withdrawal
None
Tolerance buildup
rapid
Tolerance reset
8.5 days
Dependence
Physical
None
Psychological
None
Compulsive redosing
Negligible
Dose escalation
Negligible
Cross-tol.
psychedelic 5-HT₂A agonists
Risk Shape
TOXPHYPSYWDRREDTOL

Toxicity

No LD₅₀ data, no controlled toxicity studies, and no case reports of adverse events specific to 2C-H exist.[6] The toxic dose is unknown. The compound's very weak serotonin receptor binding and probable oral inactivity suggest lower acute toxicity risk than pharmacologically active 2C compounds, but this has not been verified.

Class-level toxicity

For the 2C series as a class, toxic effects include agitation, aggression, high blood pressure, rapid heart rate, seizures, dangerously elevated body temperature, serotonin syndrome, and stimulant-like toxicity syndrome.[6] At least five deaths have been attributed to active 2C-series members (2C-E, 2C-I, 2C-B) — none involving 2C-H specifically.[6]

MAO-B-related toxicity

2C-H's potent MAO-B inhibition (IC₅₀ = 1.7 µM) introduces a toxicity risk independent of its serotonergic activity.[5] If administered by non-oral routes that bypass first-pass metabolism, systemic 2C-H could elevate dopamine and phenethylamine levels through MAO-B inhibition. Combined with even weak serotonergic activity, this dual mechanism creates interaction-mediated risks not present with most other 2C compounds.

Neurotoxicity

Cell-based studies have observed mitochondrial dysfunction and oxidative stress for 2C-T subclass compounds within the broader 2,5-dimethoxyphenethylamine family.[14] Whether the thioether substituents unique to 2C-T compounds drive this profile — or whether the shared 2C-H scaffold contributes independently — is unknown.

Psychological risks

No psychological adverse events specific to 2C-H have been documented. Given the compound's probable oral inactivity, the acute psychological risks associated with other 2C compounds — anxiety, panic, psychotic episodes, HPPD (HPPD) — are unlikely at oral doses.

If psychoactive concentrations were achieved via non-oral routes, class-level psychological risks would theoretically apply, but no data exist to characterize this scenario. inferred

Tolerance and dependence

No substance-specific tolerance or dependence data for 2C-H exist. Psychedelic serotonin 2A receptor agonists as a class produce rapid tolerance through downregulation, observable within 24 hours of a single dose.[15] Cross-tolerance occurs between psychedelic 5-HT₂A agonists but not with non-psychedelic agonists.[15]

The tolerance parameters conventionally attributed to 2C-H — rapid buildup, approximately four-day half-life, full reset in about eight days, cross-tolerance with other psychedelics — are entirely class-extrapolated values. If 2C-H does not achieve meaningful receptor occupancy at any practical dose, these parameters are pharmacologically irrelevant.

2C-H is not expected to be habit-forming.[6] No reinforcement potential, compulsive redosing, or withdrawal syndromes have been reported or would be predicted.

1LETHAL
18DANGEROUS
37CAUTION
5UNGRADED
61 rules0 SOURCE-VERIFIED2 EDITOR-REVIEWED

The interaction profile of 2C-H is shaped by its dual pharmacology: weak serotonin receptor activation combined with potent MAO-B inhibition. This combination creates interaction risks distinct from those of other 2C compounds.

Tramadol

The combination of 2C-H with tramadol is classified as dangerous. Tramadol increases serotonin levels through reuptake inhibitor and stimulation of serotonin release.[16][17] 2C-H compounds this risk through both weak serotonin receptor activation and potent MAO-B inhibition.[5] The monoamine oxidase inhibitor–tramadol combination is specifically identified as contraindicated in the pain management literature due to serotonin syndrome risk.[16]

safety citation needed No published case reports document the specific 2C-H + tramadol combination. The dangerous classification derives from mechanistic reasoning.

MAO inhibitors

2C-H's own MAO-B inhibitory activity creates a significant interaction with external MAO inhibitors.[5] Concurrent use could produce additive MAO inhibition with dangerously elevated monoamine levels.

A paradoxical activation risk also exists: MAO inhibitors could increase 2C-H's oral bioavailability by preventing the first-pass degradation that normally renders it inactive — potentially converting an inert oral dose into a psychoactive one. safety citation needed

Cannabis

No published data on the 2C-H–cannabis interaction exist. The interaction is classified as unknown.

Stimulants

Class-level concern exists for cardiovascular strain and serotonergic potentiation between 2C compounds and stimulants. 2C-H's MAO-B inhibition could theoretically potentiate stimulant effects by slowing dopamine breakdown, but this has not been studied. inferred

Contraindications

6 known
2ABSOLUTE
4RELATIVE

No substance-specific contraindication data for 2C-H exist. The following are inferred from the compound's pharmacological profile and class membership. inferred

  • Concurrent MAO inhibitor use (absolute): 2C-H's own MAO-B activity creates risk of additive monoamine oxidase inhibition and potential serotonin syndrome.
  • Concurrent tramadol use (absolute): dual serotonergic mechanism creates serotonin syndrome risk identified as contraindicated in clinical literature.
  • History of serotonin syndrome (relative): any serotonergic compound may lower the threshold for recurrence.
  • Heart conditions (relative, class-extrapolated): 2C compounds can produce elevated blood pressure and rapid heart rate, though 2C-H's weak activity makes this unlikely at oral doses.
  • Seizure disorders (relative, class-extrapolated): 2C compounds have been associated with seizures in acute toxicity; relevance to 2C-H is unclear.
  • Severe psychiatric disorders (relative, class-extrapolated): psychotic spectrum disorders and conditions worsened by serotonergic perturbation are standard contraindications for the 2C class.

Harm Reduction[edit]

Forms & Identification

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

2C-H is encountered almost exclusively in laboratory and research chemical contexts — it has no established recreational use pattern and no recognized active dose. The primary identification risk is confusion with pharmacologically active 2C-series compounds. Because 2C-H shares the same base scaffold as 2C-B, 2C-I, and 2C-E, mislabeled or contaminated material could deliver a potent psychedelic at doses assumed to be inert.

Reagent testing cannot reliably distinguish 2C-H from all 2C-series members; any material obtained outside regulated supply should be treated as unverified.

Guidelines

  • Test all material. Reagent kits and, ideally, laboratory analysis (e.g., FTIR or GC-MS through drug checking services) are the only way to verify identity and rule out contamination with active 2C analogues.
  • Do not assume inactivity. While 2C-H is considered orally inactive, material sold under this name may not be 2C-H. Treat any unverified powder as potentially active.
  • Avoid combining with MAO inhibitors. 2C-H's potent MAO-B inhibition means co-administration with MAOIs could produce unpredictable monoamine elevation or even activate the compound itself.
  • Start with the smallest possible amount if self-administration is undertaken despite the absence of established dosing. No safe dose has been determined.
  • Have a sober companion present for any exposure scenario involving an uncharacterized substance.

Set & Setting

Because 2C-H has no established psychoactive dose or confirmed subjective effects, conventional set-and-setting guidance does not apply in the usual sense. If exposure occurs — whether intentional or through mislabeled material — the standard principles hold: a calm, familiar environment with a sober companion reduces risk from unexpected effects.

The compound's unknown pharmacological profile at any achievable dose means there is no reliable basis for predicting what the experience would involve.

Aftercare & integration. If unexpected psychoactive effects occur following exposure to material labeled as 2C-H, standard psychedelic aftercare applies. Rest, hydration, and light nutrition support physical recovery. A quiet environment without demanding tasks or social obligations is appropriate for 24–48 hours following any psychoactive experience.

If distressing psychological effects persist beyond 48 hours — anxiety, perceptual disturbances, depersonalization — professional consultation is warranted. A therapist experienced with substance-related distress can help contextualize the experience. Journaling the timeline of effects, including onset, peak, and resolution, provides useful information for any future clinical encounter.

Recovery & Support

2C-H is not expected to produce dependence or compulsive use patterns. If problematic use of 2C-series compounds or research chemicals more broadly is a concern, the following resources offer support:

  • SAMHSA National Helpline (US): 1-800-662-4357 — free, confidential, 24/7 referral service
  • Talk to Frank (UK): 0300 123 6600
  • Global Drug Survey — anonymous self-assessment tools for substance use patterns
  • Local harm reduction organizations often provide non-judgmental support and referrals regardless of the specific substance involved

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

Emergency Response

Because 2C-H has no established effect profile, any unexpected reaction after ingestion of material believed to be 2C-H should be treated as a potential medical emergency — the substance may be mislabeled.

Recognizing an emergency:

Immediate steps:

  • Call emergency services immediately if any of the above are present.
  • Place an unconscious person in the recovery position (on their side, airway clear).
  • Do not induce vomiting.
  • Do not restrain a conscious person unless they are in immediate physical danger.
  • Keep the environment quiet and reduce stimulation.

What to tell the dispatcher:

  • What was taken (or what it was sold as), how much, and when
  • Current symptoms
  • Any other substances consumed
  • Good Samaritan laws in many jurisdictions protect callers from prosecution for drug-related offenses

Frequently asked questions

What is 2C-H?

2C-H is a substituted phenethylamine and the unsubstituted parent compound of the 2C psychedelic series, first synthesized in 1932. It acts as a weak 5-HT₂A partial agonist and potent MAO-B inhibitor, and is considered likely orally inactive.

Where can I find dosage information for 2C-H?

Psychedex publishes a dosage table for 2C-H 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 2C-H?

The highest-severity documented interactions for 2C-H: MAOIs (Lethal), Buspirone (Dangerous), Dopamine agonists (Dangerous), GHB, Baclofen (Dangerous), GHB, GBL (Dangerous). See the interactions section for the full list with mechanisms and severity levels.

Is 2C-H addictive?

Psychedex records tolerance and dependence data rather than a yes/no rating. Recorded tolerance indicators for 2C-H: tolerance builds rapid; full reset takes 8.5 days; cross-tolerance develops with psychedelic 5-HT₂A agonists. 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] 
    ^abcde(2024) 2C-H — Psychedelic Science Review Link
  2. [2] 
    ^abcdShulgin AT, Shulgin A (1991) PiHKAL: Phenethylamines I Have Known and Loved Link
  3. [3] 
    ^abBuck (1932) Synthesis and properties of some mescaline analogues
  4. [4] 
    ^abcdeFlanagan TW, Billac GB, Landry AN, Sebastian MN, Cormier SA, Nichols CD (2021) Structure-Activity Relationship Analysis of Psychedelics in a Rat Model of Asthma Reveals the Anti-Inflammatory Pharmacophore — ACS Pharmacology & Translational Science doi:10.1021/acsptsci.0c00063
  5. [5] 
    ^abcdefghWagmann L, Brandt SD, Stratford A, Maurer HH, Meyer MR (2019) Interactions of phenethylamine-derived psychoactive substances of the 2C-series with human monoamine oxidases — Drug Testing and Analysis doi:10.1002/dta.2494
  6. [6] 
    ^abcdefDean BV, Stellpflug SJ, Burnett A, Engebretsen KM (2013) 2C or Not 2C: Phenethylamine Designer Drug Review — Journal of Medical Toxicology doi:10.1007/s13181-013-0295-x

references

  1. [1] 
    ^abcdefghi(2024) 2C-H — Psychedelic Science Review Link
  2. [2] 
    ^abcdeShulgin AT, Shulgin A (1991) PiHKAL: Phenethylamines I Have Known and Loved Link
  3. [3] 
    ^abBuck (1932) Synthesis and properties of some mescaline analogues
  4. [4] 
    ^abcdeFlanagan TW, Billac GB, Landry AN, Sebastian MN, Cormier SA, Nichols CD (2021) Structure-Activity Relationship Analysis of Psychedelics in a Rat Model of Asthma Reveals the Anti-Inflammatory Pharmacophore — ACS Pharmacology & Translational Science doi:10.1021/acsptsci.0c00063
  5. [5] 
    ^abcdefghijWagmann L, Brandt SD, Stratford A, Maurer HH, Meyer MR (2019) Interactions of phenethylamine-derived psychoactive substances of the 2C-series with human monoamine oxidases — Drug Testing and Analysis doi:10.1002/dta.2494
  6. [6] 
    ^abcdefDean BV, Stellpflug SJ, Burnett A, Engebretsen KM (2013) 2C or Not 2C: Phenethylamine Designer Drug Review — Journal of Medical Toxicology doi:10.1007/s13181-013-0295-x
Last updated Jun 4, 2026