GLOSSARY · CHEMISTRY AND THE BODY

LSD

Also called: lysergic acid diethylamide, acid

Lysergic acid diethylamide, a classic psychedelic first made in a lab by Albert Hofmann in 1938. It is an ergoline, not a simple tryptamine, acts mainly at 5-HT2A and lasts much longer than psilocybin or DMT.

LSD is a semi-synthetic psychedelic. The Swiss chemist Albert Hofmann first made it at Sandoz in Basel in 1938, as part of research on ergot alkaloids (Omidian and Omidian, 2025). PubChem classes it as an ergoline alkaloid made by joining lysergic acid with diethylamine (PubChem, LSD); a 2011 review groups it with psilocybin and DMT as an indoleamine (Halberstadt and Geyer, 2011).

It acts mainly through 5-HT2A: ketanserin fully blocked its general subjective effects in healthy volunteers (Preller et al., 2017). A 2016 lab comparison found it binds 5-HT2A more tightly than psilocin or DMT and also touches adrenergic and dopamine receptors (Rickli et al., 2016). In a trial of 28 healthy volunteers, effects lasted about 9.3 to 11 hours on average (Holze et al., 2022).

Tolerance to LSD and psilocybin carries over between them, according to 1960s studies (Johnson et al., 2018). In Canada, LSD is in Schedule III of the Controlled Drugs and Substances Act (CDSA). This is not legal advice.

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Last checked October 26, 2026.