San Pedro cactus in the context of "Mescaline"

Mescaline, also known as mescalin or mezcalin, and in chemical terms 3,4,5-trimethoxyphenethylamine, is a naturally occurring psychedelic protoalkaloid of the substituted phenethylamine class, found in cacti like peyote (Lophophora williamsii) and San Pedro (certain species of the genus Echinopsis) and known for its serotonergic hallucinogenic effects.

Mescaline is typically taken orally and used recreationally, spiritually, and medically, with psychedelic effects occurring at doses from 100 to 1,000 mg, including microdosing below 75 mg, and it can be consumed in pure form or via mescaline-containing cacti. Mescaline induces a psychedelic experience characterized by vivid visual patterns, altered perception of time and self, synesthesia, and spiritual effects, with an onset of 0.5 to 0.9 hours and a duration that increases with dose, ranging from about 6 to 14 hours. Ketanserin blocks mescaline’s psychoactive effects, and while it's unclear if mescaline is metabolized by monoamine oxidase enzymes, preliminary evidence suggests harmala alkaloids may potentiate its effects.