# 4-AcO-DMT

4-Acetoxy-N,N-dimethyltryptamine (4-AcO-DMT or 4-acetoxy-DMT), also known as O-acetylpsilocin or psilacetin, is a psychedelic drug of the tryptamine family related to psilocybin and psilocin. It is a synthetic derivative of psilocin (4-HO-DMT) in which the hydroxyl group has been acetylated, and is the analogue of psilocybin (4-PO-DMT) in which the phosphate ester has been replaced with an acetate ester. The drug is a prodrug of psilocin and is orally active similarly to psilocybin.
As a prodrug of psilocin, 4-AcO-DMT acts as a non-selective serotonin receptor agonist, including of the serotonin 5-HT$_{2A}$ receptor. The hallucinogenic effects of psilocin are thought to be mediated by activation of this receptor, although other receptors also contribute to its effects. 4-AcO-DMT's effects are reported to be similar to those of psilocybin and psilocybin mushrooms. However, it has been said to have reduced side effects such as nausea and body load that can be caused by ingestion of whole psilocybin mushrooms. It is also said to have a faster onset and shorter duration than psilocybin. The drug is not expected to differ from psilocybin or psilocin in terms of safety. 4-AcO-DMT is modestly less potent by weight than psilocybin in animals when they are given at equimolar doses.
4-AcO-DMT was first described in a patent by Albert Hofmann in 1963 and its chemical synthesis was improved by David E. Nichols and colleagues in 1999. It was suggested by Nichols as a more economical and accessible alternative to psilocybin for use in scientific research, as the synthesis of psilocybin is more challenging and as psilocybin is a controlled substance. 4-AcO-DMT was first detected as a designer drug in Europe in 2009. It became increasingly prevalent as a recreational drug in the 2010s and has been the most commonly used novel tryptamine. In the 2020s, 4-AcO-DMT became widely encountered in the form of mushroom edibles ("legal shrooms") in the United States as a legal alternative to psilocybin. Relatedly, it has sometimes been referred to as "synthetic shrooms". Mushrooms edibles may contain 4-AcO-DMT, Amanita muscaria mushroom constituents, or non-mushroom drugs such as bath salts, and have been linked to poisonings and deaths.
4-AcO-DMT is not an explicitly controlled substance anywhere in the world as of 2023. However, it may technically be a controlled substance under laws throughout the world like the United States's Federal Analogue Act due to its close structural similarity to psilocybin and psilocin. Hence, sale and use of 4-AcO-DMT as a recreational drug exists in a legal grey area.

## Effects

Claims of subjective differences in effects between the acetylated and non-acetylated forms of psilocin vary: some users report that 4-AcO-DMT lasts slightly longer, whilst others report that it lasts for a considerably shorter time. Many users report less body load and nausea compared with psilocin. Some users find that the visual effects produced by 4-AcO-DMT more closely resemble those produced by DMT than those produced by psilocin or psilocybin. Despite the preceding reports however, there have been no controlled clinical studies to distinguish the subjective effects of psilacetin, psilocin, and psilocybin.

## Pharmacology
### Pharmacodynamics

4-AcO-DMT is a prodrug of psilocin (4-HO-DMT). As a prodrug of psilocin, 4-AcO-DMT acts as a non-selective agonist of serotonin receptors, including of the serotonin 5-HT$_{2A}$ receptor. The psychedelic effects of 4-AcO-DMT are mediated specifically by activation of the serotonin 5-HT$_{2A}$ receptor.
Similarly to psilocybin, psilocin, and other serotonergic psychedelics, 4-AcO-DMT produces the head-twitch response, a behavioral proxy of psychedelic effects, in rodents. In addition, like psilocybin and other psychedelics, 4-AcO-DMT fully substitutes for the psychedelic DOM in rodent drug discrimination tests. 4-AcO-DMT produces effects such as hypolocomotion and hypothermia in rodents as with psilocin as well.

### Pharmacokinetics

There are no clinical studies of the pharmacokinetics of 4-AcO-DMT as of 2024. However, the pharmacokinetics of 4-AcO-DMT have been studied in rodents. The drug was confirmed to act as a prodrug of psilocin similarly to psilocybin (4-PO-DMT). However, given by intraperitoneal injection at equimolar doses, 4-AcO-DMT showed only 70% of the relative bioavailability or total exposure of psilocybin. Hence, 4-AcO-DMT results in modestly lower psilocin levels than psilocybin even when the drugs are given at equivalent doses with adjustment for differences in molecular weight. Along similar lines, the psilocin concentrations with 4-AcO-DMT 15 minutes after administration were 75 to 90% of those of an equimolar dose of psilocybin. The elimination half-life of psilocin was approximately 30 minutes and did not differ between 4-AcO-DMT and psilocybin. Psilocin ester prodrugs like 4-AcO-DMT are cleaved into psilocin by esterase enzymes.

## Chemistry

4-AcO-DMT can be obtained by acetylation of psilocin under alkaline or strongly acidic conditions. It is, therefore, a synthetic compound. 4-AcO-DMT is more resistant than psilocin to oxidation under basic conditions due to its acetoxy group. It is not as difficult as psilocybin to synthesize.
Given enough time in unfavorable conditions, 4-AcO-DMT can sometimes turn into a degraded form which is brown in color and can even progress into a brown/black tar-like substance. Researchers hypothesize this is a polymerization reaction and is said to have no effect on the potency of the substance. Preliminary GCMS analysis of the closely related homologue 4-AcO-DET suggests that this degraded form of 4-AcO-DMT consists mainly of the hydroxy form of the parent molecule.
4-AcO-DMT is a lower homologue of 4-AcO-MET, 4-AcO-DET, 4-AcO-MiPT and 4-AcO-DiPT. Other analogues of 4-AcO-DMT include 4-AcO-DPT, 4-MeO-DMT, and 4-PrO-DMT (O-propionylpsilocin).

## History

4-AcO-DMT and several other esters of psilocin were patented on January 16, 1963, by Sandoz Ltd via Albert Hofmann and Franz Troxler. Despite this, psilacetin remains a psychedelic compound with a limited history of use. It is theorized to be a prodrug of psilocin, as is psilocybin, which occurs naturally in many species of psychedelic mushrooms. This is because the aromatic acetyl moiety on the 4th position of the indole ring system is subject to deacetylation in acidic conditions such as those found in the stomach. Psilacetin is O-acetylated psilocin, whereas psilocybin is O-phosphorylated.

## Society and culture
### Legal status
#### Australia

4-AcO-DMT can be considered an analog of psilocin making it a Schedule 9 prohibited substance in Australia under the Poisons Standard (October 2015). 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.

#### United States

4-AcO-DMT 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 akin to a Schedule I Controlled Substance under the Federal Analogue Act if sold for human consumption.
4-AcO-DMT is listed (often under 4-Aco-DMT) as a controlled substance at the state level in multiple states in the USA, including Alabama which has made it a schedule I at the state level on March 18, 2014, along with several other tryptamine analogs.

#### United Kingdom

4-AcO-DMT, being an ester of psilocin, is a Class A drug in the UK under the Misuse of Drugs Act 1971.

#### Czech Republic

4-AcO-DMT is prohibited in Czech republic except strictly limited research and therapeutical purposes.

#### Italy

4-AcO-DMT is illegal in Italy as it is an ester of a prohibited substance.

#### Sweden

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".

#### Israel

4-AcO-DMT is technically illegal in Israel as of being a derivative of DMT.

#### Germany

4-AcO-DMT is banned according to the BtMG since it's an ester of psilocin.