The most-used illegal substances

Methamphetamine, known by a variety of street names, including meth, crystal, glass, and ice, is an extremely addictive stimulant that is usually found as a white, odorless, bitter-tasting crystalline powder.

It is currently the most-used illegal recreational drug in China.

Methamphetamine increases the amount of the neurotransmitter dopamine, leading to high levels of the chemical in the brain. Dopamine is involved in reward, motivation, the experience of pleasure, and motor functions. Its ability to release dopamine rapidly in the "reward regions" of the brain produces a euphoric "rush" or "flash" that many users experience.