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O-Acetylpsilocin (also known as psilocetin, 4-acetoxy-DMT, or 4-AcO-DMT) is a semi-synthetic 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.[2] However, some users report that O-acetylpsilocin's subjective effects differ from that of psilocybin and psilocin.[3] It is the acetylated form of the psilocybin mushroom alkaloid psilocin and is a lower homolog of 4-AcO-MET, 4-AcO-DET, 4-AcO-MiPT and 4-AcO-DiPT.

O-Acetylpsilocin chemical structure.png
Clinical data
Synonyms4-Acetoxy-N,N-dimethyltryptamine, 3-(2'-dimethylaminoethyl)-4-acetoxy-indole[1]
Routes of
Oral, IV, intranasal, rectal
ATC code
  • none
Legal status
Legal status
  • AU: S9 (Prohibited)
  • CA: Unscheduled
  • UK: Class A
  • US: Unscheduled
CAS Number
PubChem CID
CompTox Dashboard (EPA)
Chemical and physical data
Molar mass246.3049 g/mol g·mol−1
3D model (JSmol)
Melting point172 to 173 °C (342 to 343 °F)


O-Acetylpsilocin (psilocetin) and several other esters of psilocin were patented on January 16, 1963 by Sandoz Ltd. via Albert Hofmann & Franz Troxler.[1][4] Despite this, psilocetin remains a psychedelic compound with a limited history of use. It is theorized to be a prodrug for psilocin, as is psilocybin, which occurs naturally in most species of hallucinogenic mushrooms. This is because the aromatic acetyl moiety on the 4th position is subject to deacetylation by acidic conditions such as those found in the stomach.[5] Psilocetin is O-acetylated psilocin, whereas psilocybin is O-phosphorylated.


O-Acetylpsilocin can be obtained by acetylation of psilocin under alkaline or strongly acidic conditions. It is, therefore, a semi-synthetic compound. It is believed to be a prodrug of psilocin, however, speculation that psilocetin may itself also be active exists. O-Acetylpsilocin is more resistant than psilocin to oxidation under basic conditions due to its acetoxy group. While O-acetylpsilocin is not well researched (sometimes viewed negatively as a research chemical, as opposed to psilocin and psilocybin), though it is not as difficult to produce as psilocybin. Due to their similar mechanism of action, this may further support ideas of O-acetylpsilocin possibly serving as an appropriate substitute to psilocybin for use in research of the effects psychedelic compounds in medicine.[2]


See psilocin for more details.

In the body O-acetylpsilocin is deacetylated to psilocin by deacetylases/acetyltransferases during first pass metabolism[citation needed] and during subsequent passes through the liver (evident as psilacetin is also active via parenteral routes of ingestion).

Claims of subjective differences in effect between the acetylated and non-acetylated forms of psilocin differ:[3] some users report that O-acetylpsilocin lasts slightly longer while others report that it lasts for a considerably shorter time. Many users report less body load and nausea compared to psilocin. Some users find that the visual distortions produced by O-acetylpsilocin more closely resemble those produced by DMT than those produced by psilocin. These differences could be possible if psilocetin is active itself and not merely as a prodrug. Despite this, there have been no controlled clinical studies to distinguish any effects of psilocetin, psilocin, and psilocybin from one another.

4-AcO-DMT shown in powder form



O-Acetylpsilocin can be considered an analog of psilocin making it a schedule 9 prohibited substance in Australia under the Poisons Standard (October 2015).[6] A Schedule 9 substance is a substance which may be abused or misused, the manufacture, possession, sale or use of which should be prohibited by law except when required for medical or scientific research, or for analytical, teaching or training purposes with approval of Commonwealth and/or State or Territory Health Authorities.[6]

United StatesEdit

O-Acetylpsilocin is ambiguously legal for use as a lab reagent or research chemical; however, it is an acetate ester of psilocin, meaning it would be considered Schedule I under the Federal Analogue Act if sold for human consumption.

United KingdomEdit

O-Acetylpsilocin, being an ester of psilocin, is a class A drug in the UK under the Misuse of Drugs Act 1971.[7]


O-Acetylpsilocin is illegal in Italy as it is an ester of a prohibited substance.


The Riksdag added 4-AcO-DMT to Narcotic Drugs Punishments Act under swedish schedule I ("substances, plant materials and fungi which normally do not have medical use" ) as of January 25, 2017, published by Medical Products Agency (MPA) in regulation HSLF-FS 2017:1 listed as 4-acetoxi-N,N-dimetyltryptamin.[8]

See alsoEdit


  1. ^ a b US patent 3075992, Hofmann A, Troxler F, "Esters of indoles", assigned to Sandoz Ltd. 
  2. ^ a b Nichols D, Fescas S (1999). "Improvements to the Synthesis of Psilocybin and a Facile Method for Preparing the O-Acetyl Prodrug of Psilocin" (PDF). Synthesis. 1999 (6): 935–938. CiteSeerX doi:10.1055/s-1999-3490. Archived (PDF) from the original on 17 February 2012. Retrieved 17 January 2012. Cite uses deprecated parameter |deadurl= (help)
  3. ^ a b "4-AcO-DMT (also 4-acetoxy-N,N-dimethyltryptamine) : Erowid Exp: Main Index". Archived from the original on 2010-07-28. Cite uses deprecated parameter |deadurl= (help)
  4. ^ US 3075992 
  5. ^ Staněk J, Černá MJ (January 1963). "Acidic deacetylation of sugar acetates". Tetrahedron Letters. 4 (1): 35–7. doi:10.1016/S0040-4039(01)90572-6.
  6. ^ a b "Poisons Standard October 2015". Federal Register of Legislation. Australian Government. Archived from the original on 2016-01-19. Retrieved 2016-01-06. Cite uses deprecated parameter |deadurl= (help)
  7. ^ "Misuse of Drugs Act 1971". Schedule 2 Part I, Act of 1971.
  8. ^ "Archived copy" (PDF). Archived (PDF) from the original on 2017-10-31. Retrieved 2017-04-21. Cite uses deprecated parameter |deadurl= (help)CS1 maint: archived copy as title (link)

External linksEdit