Major psychedelic drugs include mescaline, LSD, psilocybin, and DMT. Serotonergic psychedelics like psilocybin, LSD, and mescaline act as 5-HT receptor agonists. These trials tested the effects of LSD, psilocybin, mescaline, and other psychedelic drugs. Delay pioneered research on drugs including LSD, mescaline, and psilocybin. Micropsia can result from the action of mescaline and other hallucinogenic drugs. Donovan's drug use was mostly restricted to cannabis, with occasional use of LSD and mescaline. The TMAs are analogs of the phenethylamine cactus alkaloid mescaline. And then I started taking LSD and mescaline. At the time only Mescaline and the Peyote cactus were illegal. Alkaloid extraction yielded approximately 2% of the alkaloids including mescaline in both samples. In the spring of 1953, Huxley had his first experience with the psychedelic drug mescaline. Tyrosine and phenylalanine serve as the metabolic precursors to synthesis of mescaline. They were given 100 milligrams of mescaline. This final methylation step results in the production of mescaline. An unusual but unique characteristic of mescaline use is the "geometricization" of three-dimensional objects.