A group of synthetic stimulants, with structures based in phenyl amines. Amphetamine itself has the formula

Methamphetamine has a methyl group on the amino group, i.e.

The hydrochloride of methamphetamine can be crystallized giving a particularly powerful form known as ‘ice’ or crystal meth. Other examples of amphetamines are ecstasy and mescaline. In the UK, amphetamines are class B controlled substances (or class A if prepared for injection).