What's the difference between methamphetamine & amphetamines?

Answer 1

Chemically, methamphetamine possesses an N-methyl group which amphetamine lacks; otherwise, the compounds are identical. This structural modification results in methamphetamine being a more powerful stimulant and euphoriant. However, methamphetamine is also more toxic than amphetamine.

It should be noted that methamphetamine and amphetamine can exist as two distinct enantiomers (mirror image compounds). In amphetamine, both are active and have generally similar effects. However, the enantiomers of methamphetamine vastly differ in their pharmacological properties. The dextro (S) compound is a powerful centrally-acting stimulant, while levo (R) isomer has little CNS activity.