4-AcO-DMT

Psychedelic

4-AcO-DMT (psilacetin, O-acetylpsilocin) is a synthetic tryptamine that acts as a prodrug for psilocin — the same active compound produced by magic mushrooms. Its effects are widely reported to be very similar to psilocybin.

Also known as: Psilacetin, O-Acetylpsilocin, 4-Acetoxy-DMT, 4-AcO-DMT, Psilocetin, 4-Acetoxy-N,N-dimethyltryptamine

Written by Psymerge Editorial Team · Last updated June 4, 2026

Key facts

Category
Psychedelic
Onset
20–40 minutes (oral)
Peak
1.5–3 hours
Total duration
4–6 hours
After-effects
Mild afterglow, tiredness or lingering mood changes for a few hours

Overview

4-AcO-DMT, also called psilacetin or O-acetylpsilocin, is a laboratory-made tryptamine closely related to psilocybin and psilocin. Chemically it is the acetate ester of psilocin (4-HO-DMT) and the close analogue of psilocybin (in which a phosphate group is replaced by an acetate group). After ingestion it is converted by the body into psilocin, so its effects are generally described as comparable to those of psilocybin mushrooms.

Because it can be synthesised more easily and cheaply than psilocybin, researchers have proposed psilacetin as a practical substitute in preclinical studies, and a rodent study has directly confirmed it acts as a psilocin prodrug, yielding modestly lower psilocin exposure than equimolar psilocybin (Wenthur and colleagues, Frontiers in Psychiatry, 2023). There are no published clinical pharmacokinetic studies in humans, and it is most often encountered as an unregulated research chemical. This page is educational and is not an endorsement of use.

History & origins

The O-acetyl prodrug of psilocin was patented by Albert Hofmann and Franz Troxler at Sandoz around 1963, during the same era of Sandoz tryptamine research that produced psilocybin. A convenient synthesis was later published by David Nichols and Stewart Frescas (1999), who suggested psilacetin as an easier-to-make alternative to psilocybin. It subsequently appeared in the unregulated research-chemical market and has become one of the more common synthetic psilocin prodrugs (Nichols & Frescas, 1999; Chadeayne et al., 2019).

Pharmacology & how it works

4-AcO-DMT is a prodrug: after ingestion, esterase enzymes cleave the acetate group to release psilocin (4-HO-DMT). Psilocin is a non-selective serotonin receptor agonist, and its psychedelic effects are mediated chiefly by activation of the serotonin 5-HT2A receptor — the same mechanism as psilocybin (Dinis-Oliveira, 2017; Nichols, 2016).

Chemical class
Synthetic substituted tryptamine; acetate ester (prodrug) of psilocin (4-HO-DMT) and analogue of psilocybin
Routes of administration
Oral (powder, capsule, or pellet)
Tolerance
Rapid tolerance develops with consecutive-day use and resets after several days of abstinence; cross-tolerance with psilocybin and LSD is expected.

Pharmacokinetics

Oral effects typically begin within 20–40 minutes and last about 4–6 hours. In rodents, psilacetin behaves as a psilocin prodrug like psilocybin but, at equimolar doses, produced modestly lower psilocin exposure (around 70% of psilocybin's). The half-life of the resulting psilocin is short (roughly half an hour). No human clinical pharmacokinetic studies have been published (Wenthur et al., 2023).

Effects

Physical Effects

  • Pupil dilation
  • Changes in heart rate and blood pressure
  • Nausea, especially as effects begin
  • Altered coordination
  • Yawning, chills or tingling

Psychological Effects

  • Visual alterations — patterns, intensified colours, movement
  • Shifts in mood, often euphoric but sometimes anxious
  • Altered sense of time and self
  • Introspection and emotional insight
  • Anxiety, fear or confusion at higher doses or in poor settings

Spiritual Effects

  • Feelings of connection or unity
  • Mystical-type or ego-dissolution experiences at higher doses

Dosage Information

Low: 5–10 mg (oral)
Medium: 10–25 mg (oral)
High: 25–40+ mg (oral)

Roughly comparable in potency to psilocybin by weight. Because it is sold as a powder or in pellets of uncertain purity, accurate dosing requires a precise milligram scale; misweighing is a real risk. Start low, especially with an unverified source. Educational only and not an endorsement of use.

Risks & safety

Contraindications

As a serotonergic psychedelic acting through psilocin, 4-AcO-DMT shares psilocybin's main cautions. It is generally not advised for:

  • Psychiatric history: a personal or family history of psychosis, schizophrenia, or bipolar disorder, which psychedelics may trigger or worsen.
  • Serotonergic and other medication: especially lithium and tramadol (see interactions), and MAOIs and SSRIs.
  • Cardiovascular conditions: psilocin has some activity at heart-related serotonin receptors, so significant heart disease warrants caution.
  • Other: pregnancy and breastfeeding, where safety is unknown.

Drug interactions

Key interactions mirror those of psilocybin:

  • Lithium: combining lithium with psychedelics has been linked to seizures and serious adverse events and should be avoided.
  • Tramadol: raises the risk of seizures and serotonin syndrome.
  • MAOIs: can substantially intensify and prolong effects.
  • SSRIs/SNRIs: often blunt the effects; combining serotonergic drugs also carries some serotonin-syndrome risk.

This list is not exhaustive. Check an up-to-date interaction resource and consult a clinician about any prescription medication (TripSit; NIDA).

Psychological distress & bad trips

Like psilocybin, 4-AcO-DMT can produce challenging experiences — anxiety, fear, paranoia, or confusion ('bad trips') — particularly at higher doses, with an unprepared mindset, or in an unsafe setting. These are usually temporary and are made less likely by careful attention to dose, set and setting and the presence of a sober trip-sitter.

Rare but serious risks

Physiologically, psilocin-type psychedelics have low toxicity, but real risks remain:

  • Accidents and risky behaviour due to impaired judgement and perception.
  • Triggering or worsening psychosis in vulnerable individuals.
  • Hallucinogen Persisting Perception Disorder (HPPD): rare, lasting visual disturbances.
  • Research-chemical uncertainty: as an unregulated product, purity and exact content are not guaranteed, and dosing errors are easy with potent powders.

Vulnerable populations

Those who should be especially cautious or avoid use include people with a personal or family history of psychosis, schizophrenia or bipolar disorder; adolescents and young adults, whose brains are still developing; people taking lithium, tramadol or serotonergic medication; and those who are pregnant or breastfeeding.

Dependency & addiction potential

4-AcO-DMT is not considered addictive and does not produce physical dependence or withdrawal. Like other classic psychedelics it causes rapid tolerance — effects diminish sharply with use on consecutive days — which itself discourages frequent use.

Overdose

There is no established lethal dose, and the physiological margin of safety for psilocin-type psychedelics is wide. The greater dangers from a very large dose are overwhelming psychological distress and dangerous behaviour rather than direct toxicity. Because 4-AcO-DMT is a potent powder of uncertain purity, accidental overdose from misweighing is a genuine concern; seek medical help for severe agitation, chest pain, or a medical emergency.

Harm Reduction

  • Treat it like psilocybin: pay careful attention to dose, mindset (set) and environment (setting).
  • Use a precise milligram scale — 4-AcO-DMT is active in milligrams and easy to misweigh.
  • Where possible, verify the substance with a reagent test; research-chemical products vary in purity.
  • Start low, especially with a new batch, and wait before considering any redose.
  • Have a sober, trusted trip-sitter present and a safe, comfortable space.
  • Never combine with lithium or tramadol, and avoid MAOIs; do not adjust prescription medication to use it.
  • Avoid if you have a personal or family history of psychosis or bipolar disorder.

Microdosing

Some people microdose 4-AcO-DMT in the same way as psilocybin, taking sub-perceptual amounts on an intermittent schedule. There is no clinical evidence specific to 4-AcO-DMT, and dosing is complicated by the uncertain purity of research-chemical products.

Common protocols

  • Anecdotally, roughly 1–3 mg taken occasionally (for example every few days), by analogy with psilocybin microdosing — not a validated protocol.

Evidence

No controlled human trials have studied microdosing 4-AcO-DMT specifically. Evidence is limited to anecdote and to broader psilocybin microdosing research, which to date shows mixed results and significant placebo effects.

Legal Status

Laws vary widely by country and change frequently, so we don't track legal status here to avoid showing outdated information.

Check current worldwide legal status on Psychedelic Alpha

Frequently asked questions

Is 4-AcO-DMT the same as psilocybin?

Not identical, but very close. 4-AcO-DMT is a synthetic prodrug that the body converts to psilocin — the same active compound psilocybin produces — so users report broadly similar effects. A rodent study confirmed it acts as a psilocin prodrug, with slightly lower psilocin exposure than equimolar psilocybin (Wenthur et al., 2023).

How long does 4-AcO-DMT last?

Taken orally, effects usually begin within 20–40 minutes, peak over 1.5–3 hours, and last around 4–6 hours, often with a mild afterglow afterwards.

Is 4-AcO-DMT dangerous?

Its physiological toxicity is low, but risks include challenging psychological experiences, accidents from impaired judgement, triggering psychosis in vulnerable people, and — because it is an unregulated powder — dosing errors and uncertain purity. Avoid combining it with lithium or tramadol.

Is 4-AcO-DMT addictive?

No. It is not considered addictive and does not cause physical dependence. Like other classic psychedelics it produces rapid tolerance, which discourages frequent use.

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References & further reading

  • Nichols, D. E., & Frescas, S. (1999). Improvements to the synthesis of psilocybin and a facile method for preparing the O-acetyl prodrug of psilocin. Synthesis, 1999(6), 935–938.
  • Chadeayne, A. R., Golen, J. A., & Manke, D. R. (2019). Bis(4-acetoxy-N,N-dimethyltryptammonium) fumarate: a new crystalline form of psilacetin, an alternative to psilocybin as a psilocin prodrug. Acta Crystallographica Section E, 75, 900–902. https://doi.org/10.1107/S2056989019007370
  • Dinis-Oliveira, R. J. (2017). Metabolism of psilocybin and psilocin: clinical and forensic toxicological relevance. Drug Metabolism Reviews, 49(1), 84–91. https://doi.org/10.1080/03602532.2016.1278228
  • Nichols, D. E. (2016). Psychedelics. Pharmacological Reviews, 68(2), 264–355. https://doi.org/10.1124/pr.115.011478
  • In vivo validation of psilacetin as a prodrug yielding modestly lower peripheral psilocin exposure than psilocybin. Frontiers in Psychiatry (2023), 14, 1303365. https://doi.org/10.3389/fpsyt.2023.1303365
  • Johnson, M. W., Richards, W. A., & Griffiths, R. R. (2008). Human hallucinogen research: guidelines for safety. Journal of Psychopharmacology, 22(6), 603–620. https://doi.org/10.1177/0269881108093587
  • Erowid. 4-AcO-DMT (4-Acetoxy-DMT) Vault. https://www.erowid.org/chemicals/4_acetoxy_dmt/
  • TripSit. 4-AcO-DMT factsheet and drug combinations. https://drugs.tripsit.me/4-aco-dmt

About this article

Written by:
PE
Psymerge Editorial Team
Last updated June 4, 2026