2C-H
2,5-dimethoxyphenethylamine
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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]
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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.
The name "2C-H" follows Shulgin's nomenclature: "2C" for the two-carbon chain, "H" for hydrogen — the absence of a 4-position substituent. A common source of confusion: "DMPEA" in scientific literature almost always refers to 3,4-dimethoxyphenethylamine — a positional isomer investigated in connection with a schizophrenia hypothesis[8] — not 2C-H (the 2,5-isomer). The two are structurally and pharmacologically distinct.
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 formula | C₁₀H₁₅NO₂ |
| Molecular weight | 181.23 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]
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.
- Can non-oral administration bypass MAO-B degradation sufficiently to achieve meaningful brain concentrations, and would the resulting experience be dominated by calming serotonin signaling?
- What is the precise mechanism by which the 2,5-dimethoxyphenethylamine scaffold confers anti-inflammatory activity?
- Does 2C-H promote new brain connections at any dose, and if so, through which pathways?
Subjective Effects[edit]
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.
Effect Grid
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.
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
Timeline
No onset has been characterized. 2C-H is believed to be orally inactive due to rapid MAO-B first-pass metabolism. Shulgin listed duration as 'unknown' in PiHKAL.
No peak effects have been documented. The compound's weak 5-HT₂A affinity (Ki 1,600 nM) and MAO-B vulnerability preclude meaningful psychoactive response at oral doses.
No afterglow period has been characterized. No subjective effects timeline exists for 2C-H by any route.
⚠ Do not drive or operate machinery after ingesting any uncharacterized research chemical.
Safety[edit]
- Acute toxicity
- Negligible
- Chronic toxicity
- No data
- Withdrawal
- None
- Tolerance buildup
- rapid
- Tolerance reset
- 8.5 days
- Physical
- None
- Psychological
- None
- Compulsive redosing
- Negligible
- Dose escalation
- Negligible
- Cross-tol.
- psychedelic 5-HT₂A agonists
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]
2C-H is not expected to be habit-forming.[6] No reinforcement, compulsive redosing, or withdrawal has been reported or would be predicted.
Drug interactions
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
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
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:
- Rapid heart rate, chest pain, or difficulty breathing
- Seizures or loss of consciousness
- Severe agitation, confusion, or inability to communicate
- Body temperature that feels elevated through clothing
- Signs of serotonin syndrome: muscle rigidity, rapid eye movements, extreme agitation, high fever
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
Legal Status[edit]
2C-H is controlled in multiple jurisdictions under provisions targeting the 2C phenethylamine structural class broadly, not based on evidence of 2C-H-specific harm or abuse.
| Jurisdiction | Classification | Key provisions |
|---|---|---|
| United States | Schedule I (Controlled Substances Act) | Classified under the Synthetic Drug Abuse Prevention Act of 2012, effective July 9, 2012[7] |
| United Kingdom | Class A (Misuse of Drugs Act 1971) | Covered under catch-all phenethylamine provisions; also subject to the Psychoactive Substances Act 2016[7] |
| Canada | Schedule III (CDSA) | Scheduled October 31, 2016 under the Controlled Drugs and Substances Act[7] |
| Germany | Anlage I (BtMG) | Controlled under the Narcotics Act; 2C-x class covered[7] |
| Australia | Likely Schedule 9 (prohibited) | Blanket coverage of substituted phenethylamines; explicit 2C-H entry not confirmed in SUSMPcitation needed |
Analogue act considerations
2C-H's direct scheduling makes structural analog prosecution unnecessary. Its classification despite probable pharmacological inactivity illustrates how structural-class scheduling works: legal status derives from molecular similarity to active compounds, not from demonstrated risk of the individual substance.
references
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- [6]