Norbaeocystin is a psilocybin mushroom alkaloid and analog of psilocybin. It is found as a minor compound in most psilocybin mushrooms together with psilocin, psilocybin and baeocystin, from which it is a derivative. Norbaeocystin is a N-demethylated derivative of baeocystin (itself a N-demethylated derivative of psilocybin), and a phosphorylated derivative of . The latter is notable as a positional isomer of serotonin, which is 5-hydroxytryptamine.