Lysergic acid diethylamide

Lysergic acid diethylamide (/daɪ eθəl ˈæmaɪd/ or /æmɪd/ or /eɪmaɪd/), abbreviated LSD or LSD-25, also known as lysergide (INN) and colloquially as acid, is a psychedelic drug of the ergoline family, well known for its psychological effects—which can include altered thinking processes, closed- and open-eye visuals, synesthesia, an altered sense of time, and spiritual experiences—as well as for its key role in 1960s counterculture. It is used mainly as an entheogen and recreational drug. LSD is not addictive. However, acute adverse psychiatric reactions such as anxiety, paranoia, and delusions are possible.

LSD was first synthesized by Albert Hofmann in 1938 from ergotamine, a chemical derived by Arthur Stoll from ergot, a grain fungus that typically grows on rye. The short form "LSD" comes from its early code name LSD-25, which is an abbreviation for the German "Lysergsäure-diethylamid" followed by a sequential number. LSD is sensitive to oxygen, ultraviolet light, and chlorine, especially in solution, though its potency may last for years if it is stored away from light and moisture at low temperature. In pure form it is a colorless, odorless, tasteless solid. LSD is typically either swallowed (oral) or held under the tongue (sublingual), usually on a substrate such as absorbent blotter paper, a sugar cube, or gelatin. In its liquid form, it can also be administered by intramuscular or intravenous injection. Interestingly, unlike most other classes of illicit drugs and other groups of psychedelic drugs such as tryptamines and phenethylamines, when LSD is administered via intravenous injection the onset is not immediate, instead taking approximately 30 minutes before the effects are realized. LSD is very potent, with 20–30 µg (micrograms) being the threshold dose.