O-Acetylpsilocin (also known as psilacetin, 4-acetoxy-DMT, or 4-AcO-DMT) is a synthetically produced psychoactive drug and has been suggested by David Nichols to be a potentially useful alternative to psilocybin for pharmacological studies, as they are both believed to be prodrugs of psilocin. However, some users report that O-acetylpsilocin's subjective effects differ from that of psilocybin and psilocin. It is the acetylated form of the psilocybin mushroom alkaloid psilocin and is a lower homolog of 4-AcO-DET, 4-AcO-MiPT and 4-AcO-DiPT.