4-AcO-DMT

4-AcO-DMT (4-acetoxy-N,N-dimethyltryptamine, psilacetin, O-acetylpsilocin) is a semisynthetic tryptamine and the acetate ester of psilocin, the active metabolite of psilocybin. It functions largely as a prodrug: ester hydrolysis yields psilocin, a high-efficacy agonist at the 5-HT2A serotonin receptor that mediates its psilocybin-like psychedelic effects. In vitro studies with human liver microsomes confirm that hydrolysis to psilocin is the dominant biotransformation, followed by glucuronidation and oxidation. Structure-activity work shows that acetylation reduces 5-HT2A potency in cell assays yet has little effect on the mouse head-twitch response, consistent with in vivo deacetylation, and the compound fully substitutes for DOM in drug-discrimination assays. It has become one of the more widely encountered designer tryptamines, valued for its comparative chemical stability relative to mushroom material.