Baeocystin is a psilocybin mushroom alkaloid and analog of psilocybin. It is found as a minor compound in most psilocybin mushrooms together with psilocybin, norbaeocystin, and psilocin. Baeocystin is a N-demethylated derivative of psilocybin, and a phosphorylated derivative of 4-HO-NMT (4-hydroxy-N-methyltryptamine). The structures at right illustrate baeocystin in its zwitterionic form.