Ball-and-stick model of the 4-methylamphetamine molecule
Systematic (IUPAC) name
Clinical data
Legal status
Routes of
Oral, intranasal, injection
Pharmacokinetic data
Biological half-life 6-12 hours
Excretion Urine
CAS Registry Number  N
ATC code None
PubChem CID:
ChemSpider  YesY
Chemical data
Formula C10H15N
Molecular mass 149.23 g/mol

4-Methylamphetamine (4-MA; PAL-313; Aptrol; p-TAP) is a stimulant and anorectic drug of the phenethylamine and amphetamine chemical classes.

In vitro, it acts as a potent and balanced serotonin, norepinephrine, and dopamine releasing agent with Ki affinity values of 53.4nM, 22.2nM, and 44.1nM at the serotonin, norepinephrine, and dopamine transporters, respectively.[1] However, more recent in vivo studies that involved performing microdialysis on rats showed a different trend. These studies showed that 4-methylamphetamine is much more potent at elevating serotonin (~18 x baseline) relative to dopamine (~5 x baseline). The authors speculated that this is because 5-HT release dampens DA release through some mechanism. For example, it was suggested that a possible cause for this could be activation of 5HT2C receptors since this is known to inhibit DA release. In addition there are alternative explanations such as 5-HT release then going on to encourage GABA release, which has an inhibitory effect on DA neurons.[2]

4-MA was investigated as an appetite suppressant in 1952 and was even given a trade name, Aptrol, but development was apparently never completed.[3] More recently it has been reported as a novel designer drug.

In animal studies, 4-MA was shown to have the lowest rate of self-administration out of a range of similar drugs tested (the others being 3-methylamphetamine, 4-fluoroamphetamine, and 3-fluoroamphetamine), likely as a result of having the highest potency for releasing serotonin relative to dopamine.[4][5]

More than a dozen deaths have been reported throughout Europe in 2012-2013 after consumption of amphetamine ('speed') contamined with 4-methylamphetamine.

Since 4-MA has little, if any, desirable psychoactive properties, researchers doubt the substance was sold as amphetamine on purpose. A contaminated precursor, after synthesis yielding a mixture of amphetamine and 4-MA, seems the logical culprit.[6]


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