Methamphetamine is a member of the class of amphetamines in which the amino group of (S)-amphetamine carries a methyl substituent. It has a role as a neurotoxin, a psychotropic drug, a central nervous system stimulant, a xenobiotic and an environmental contaminant. It is a member of amphetamines and a secondary amine. It is functionally related to a (S)-amphetamine. It is a conjugate base of a methamphetamine(1+).