Mephedrone (4-MMC)
Mephedrone (4-methylmethcathinone, 4-MMC) is a synthetic cathinone that acts as a combined stimulant and entactogen, releasing dopamine, noradrenaline and serotonin. It became widely used from around 2009 as a 'legal high' before scheduling in most jurisdictions. Human data are limited to surveys, emergency-department case series and post-hoc pharmacology; there are no controlled dosing trials.
01 Overview
Mephedrone was one of the first substituted cathinones to see mass recreational use, marketed as 'meow meow' or 'bath salts' before control. Users report euphoria, sociability and stimulation resembling a blend of MDMA and amphetamine, with a short duration that drives compulsive redosing. It is taken orally or insufflated, and the intense but brief effects are a recognised risk factor for binge patterns.
What is known comes largely from monitoring systems (EUDA/EMCDDA), toxicology and animal pharmacology rather than clinical trials. Reported harms include marked cardiovascular strain, a severe comedown, and unknown long-term neurotoxicity. Long-term neurotoxicity in humans remains uncharacterised and is marked unconfirmed throughout.
02 Mechanism
Acts as a non-selective monoamine releasing agent and reuptake inhibitor at dopamine, noradrenaline and serotonin transporters, producing combined stimulant and entactogenic effects.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Light | 25–75 mg | Insufflated | Faster, more intense onset; harsh and painful nasally. |
| Light | 75–150 mg | Oral | Onset ~15-45 min orally; effects short-lived. |
| Common | 75–125 mg | Insufflated | Strong compulsion to redose within the hour. |
| Common | 150–225 mg | Oral | Redosing common due to short duration. |
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Euphoria and sociabilityUsers report MDMA-like warmth and empathy combined with amphetamine-like stimulation. | marked, short-lived | Anecdotal | |
| Stimulation and increased energyWakefulness, talkativeness and raised drive typical of releasing-agent stimulants. | Anecdotal | ||
| Compulsive redosingThe brief duration and rapid comedown drive a strong urge to redose, reported consistently in user surveys. | Observational |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| Severe comedownLow mood, anxiety, irritability and craving following use, worsened by bingeing. | Moderate | Very common | Observational | |
| Long-term neurotoxicity (unknown)Potential for serotonergic or dopaminergic neurotoxicity is suggested by animal data but not established in humans. | Moderate | Unknown | Unconfirmed | |
| Cardiovascular strainTachycardia, palpitations, hypertension and chest pain reported to poison centres and emergency departments. | Severe | Common | Observational |