4-CMA (4-Chloromethamphetamine)
4-CMA (para-chloromethamphetamine, PCMA) is a ring-chlorinated methamphetamine analogue and potent serotonin-releasing agent. Unlike the beta-keto cathinones, it is a non-ketone amphetamine, but it circulated in the same research-chemical niche. It is notable for marked serotonergic neurotoxicity in animals and a high serotonin-syndrome risk, with essentially no legitimate human use.
01 Overview
4-CMA is the 4-chloro analogue of methamphetamine, closely related to the neurotoxic serotonin releaser PCA. It is a potent serotonin-releasing agent rather than a euphoriant, and reports describe an unpleasant, anxiogenic and physically taxing experience rather than a recreational stimulant high.
The dominant hazards go beyond the usual class profile: on top of compulsive redosing, cardiovascular strain and comedown, 4-CMA carries a substantial risk of serotonin syndrome and documented serotonergic neurotoxicity in animal studies. There are no controlled human studies, so figures are approximate and drawn from sparse reports and analogy to related serotonin releasers.
02 Mechanism
Potent serotonin-releasing agent with additional noradrenergic and dopaminergic release; the para-chloro substituent markedly increases serotonergic potency and neurotoxic potential, as seen with related para-substituted amphetamines.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Common | 10–40 mg | Insufflated | Faster, harsher; not recommended given toxicity. |
| Common | 20–60 mg | Oral | Anecdotal; narrow margin, serotonergic toxicity risk. |
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| StimulationEnergy and wakefulness, often described as edgy. | Anecdotal | ||
| Appetite suppressionMarked reduction in hunger during effects. | Anecdotal | ||
| Anxiety and uneaseRestlessness and dysphoria reported, reflecting the strong serotonergic action. | Anecdotal |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| Serotonin syndromeHyperthermia, agitation, tremor, clonus and autonomic instability from excessive serotonin release. | Life-threatening | Dose-dependent | Unconfirmed | |
| Serotonergic neurotoxicityLasting depletion of serotonergic markers demonstrated in animals; human relevance unquantified. | Severe | Unknown in humans | Unconfirmed | |
| Cardiovascular strainTachycardia, hypertension and hyperthermia. | Severe | Common | Unconfirmed |