GBL
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Gamma Butyrlactone (GBL) was once marketed as a sort of cure-all, with companies offering it up as a sleep inducer, aphrodisiac, antidepressant, weight-loss aid, and hair thickener, but it was really just a way to get high. The body converts GBL into gamma hydroxybutyrate (GHB), which is increasingly used as a date-rape drug. The government banned GBL after learning that it could cause comas and death, with other consumers reporting vomiting, extreme agitation, difficulty breathing, uncontrolled twitching, and loss of bowel control. It's also believed to have caused ex-NBA forward Tom Gugliotta to suffer a seizure. GBL is now illegal to manufacture, unless you're selling it as an industrial solvent, but some users have managed to extract it from nail polish remover.