The most popular illegal amphetamines are methamphetamine and MDMA.
Methamphetamine (or “meth”) is a highly addictive stimulant drug that’s available as a powder or smokeable rock (also called “crystal meth”). MDMA is a stimulant and hallucinogen that’s available as a capsule, tablet, powder, or liquid.
In addition, prescription amphetamines (such as Adderall and Vyvanse) are illegal when used without a prescription.