4-AcO-DET

4-Acetoxy-N,N-diethyltryptamine

Ethacetin, Ethylacybin, 4-Acetoxy-DET

Psychoactive Class

Chemical Class

4-AcO-DET is a synthetic psychedelic of the tryptamine class¹, first synthesized by Albert Hofmann at the Sandoz laboratory in 1958. It is chemically related to psilocin and belongs to a series of substituted tryptamines that includes 4-AcO-MET and 4-AcO-DMT. Its effects are generally compared to those of psilocybin mushrooms.² It remains a lesser-known research chemical, typically encountered as a slightly off-white powder and most commonly administered orally.

Dosage & Duration

Dosage

Threshold2-5 mg

Light5-15 mg

Moderate15-20 mg

Strong20-35 mg

Heavy35+ mg

Duration

Onset20-60 minutes

Come Up1-1.5 hours

Peak1.5-3 hours

Offset1-2 hours

After Effects2-4 hours

Total4-7 hours

Subjective Effects

Effects vary widely by individual, dose, and context.

Adapted from the 4-HO-DET subjective effects documentation. 4-AcO-DET is the acetylated prodrug of 4-HO-DET and is reported to produce an effectively identical experience. Forked from Subjective Effect Documentation work

by Josie KinsAugust 2016.

Reagent Testing

Expected colorimetric results for common reagent tests. Colors show reaction change over 1–2 minutes.

Marquis(MQ)

Mecke(ME)

Liebermann(LB)

Froe(FR)

PROtestkit.eu

Pharmacology

Pharmacodynamics

In HEK-cell assays expressing individual human serotonin receptors, 4-AcO-DET bound and activated 5-HT2A, 5-HT2C, and 5-HT1A receptors. It had the highest affinity and potency of these three at 5-HT2A (Ki 248 ± 26 nM; EC50 309 ± 97 nM) and produced 79.1% ± 4.7% of the 5-HT maximum in the study's IP-1 assay.³

These in-vitro results demonstrate intrinsic serotonergic activity of 4-AcO-DET, but they do not establish how much of the human effect is produced by the parent compound versus its O-deacetylated metabolite, 4-HO-DET.³⁴

Pharmacokinetics

A 2024 metabolism study observed O-deacetylation of 4-AcO-DET to 4-HO-DET in pooled human liver S9 fractions and zebrafish larvae. The study identified four phase I and one phase II metabolite in the liver model and ten phase I and two phase II metabolites in zebrafish larvae; the assignments were tentative because reference standards for the metabolites were unavailable.⁴ Recombinant-enzyme experiments implicated CYP1A2, CYP2C8, CYP2C19, CYP2D6, and CYP3A4 in N-deethylation; several CYP isoforms in hydroxylation; and CYP2C9, CYP3A4, and FMO3 in N-oxide formation. These model-based results identify candidate pathways and analytical biomarkers, not human bioavailability, conversion rate, clearance, or half-life.⁴

Interactions

Dangerous

Highest risk

These combinations are considered extremely harmful and should always be avoided. Reactions to these drugs taken in combination are highly unpredictable and have a potential to cause death.

Lithium

Unsafe

Avoid

There is considerable risk of physical harm when taking these combinations, they should be avoided where possible.

Tramadol

Caution

Use caution

These combinations are not usually physically harmful, but may produce undesirable effects, such as physical discomfort or overstimulation. Extreme use may cause physical health issues. Synergistic effects may be unpredictable. Care should be taken when choosing to use this combination.

AmphetaminesCannabisCocaineDiphenhydramine

TripSit

Tolerance

Full Tolerance

4-AcO-DET can produce tolerance very soon after it is taken.¹

Baseline Reset

Approximately 7 days

Half Tolerance

Approximately 3 days

Cross Tolerance

Serotonergic psychedelics

Harm Potential

Addiction & Dependence

Psychological

Extremely Low

4-AcO-DET is believed to be not habit-forming¹⁶, and the desire to use it may actually decrease with repeated use.

Psychosis Risk

Delusions are listed as a potential cognitive effect during intoxication, but no systematic data exists on intrinsic psychosis risk.

Seizure Risk

No intrinsic seizure risk has been documented for this substance.

History & Culture

4-AcO-DET was first synthesized in 1958 by Albert Hofmann at the Sandoz laboratories in Switzerland. Despite this early synthesis, the compound remained largely unexplored for decades and has accumulated very little documented history of human usage.²…

Trip Reports

Legality

International

4-AcO-DET is not listed in the current schedules of the 1961 Single Convention or the 1971 Convention on Psychotropic Substances, or in Tables I and II of the 1988 Convention.

By Country

United StatesUnscheduled

Not federally scheduled under the Controlled Substances Act. However, as a structural analogue of psilocin (4-HO-DMT), which is a Schedule I substance²⁴, sale for human consumption or use for illicit purposes could potentially be prosecuted under the Federal Analogue Act.²⁵

BrazilIllegalList F2

Portaria SVS/MS No. 344/1998, List F2⁹

Brazil’s controlled-substances list places 4-acetoxy-N,N-diethyltryptamine in List F2. List F2 is the national list for psychotropic substances of proscribed use.

GermanyAnlage I BtMGCitation needed

Controlled under Anlage I of the Betäubungsmittelgesetz (Narcotics Act) since January 24, 1974, as it is classified as an ester of DET.¹¹ Manufacturing, possession, importation, exportation, purchase, sale, and distribution are prohibited without a license.¹²

NorwayIllegalNarcotics list

Forskrift om narkotika (narkotikaforskriften)¹⁵¹⁶

Norway lists 4-AcO-DET in the narcotics regulation. The named listing places the substance within Norway’s narcotic-substance controls.

SwitzerlandControlled (Verzeichnis E)Citation needed

Specifically named as a controlled substance under Verzeichnis E since November 1, 2005, pursuant to the Act on the Prohibition of Certain Goods Dangerous to Health.

United KingdomIllegalClass A

Misuse of Drugs Act 1971, Schedule 2²³

Controlled as a Class A substance due to its status as an ester of 4-HO-DET, which falls under the tryptamine catch-all clause of the Misuse of Drugs Act 1971.²³ Carries the most severe penalties for possession, production, and supply.

BelgiumIllegal (analog/blanket ban)Tryptamine derivative

Royal Decree of 6 September 2017 regulating narcotic and psychotropic substances, Annex IVa⁷⁸

4-AcO-DET falls within Annex IVa's generic tryptamine-derivative definition. Its N,N-diethyl substitution is permitted at R1 and R2, and its 4-acetoxy substituent is an OAc group permitted at R3 at any position on the indole six-membered ring. Annex IVa substances are nationally listed and subject to the Royal Decree's controlled-substance regime.

DenmarkIllegal (analog/blanket ban)Tryptamine group ester

Bekendtgørelse om euforiserende stoffer (BEK nr 405 af 26. marts 2026)¹⁰

4-AcO-DET is covered as an ester derivative of a controlled tryptamine-group substance. List B covers the tryptamine group, including compounds derived from hydroxytryptamine by alkyl substitution on the side-chain nitrogen, and the order includes simple psychoactive derivatives such as esters of listed substances. List B substances may only be used for medical and scientific purposes.

JapanControlled

Designated as a controlled substance¹³¹⁴ effective July 29, 2015, under national drug control legislation.

SwedenRestrictedHealth-hazard good

Förordning (1999:58); Lag (1999:42)¹⁷¹⁸

Classified as a health hazard under Lagen om förbud mot vissa hälsofarliga varor (Act on the Prohibition of Certain Goods Dangerous to Health) effective November 1, 2005, under regulation SFS 2005:733.¹⁹ Possession and sale are illegal.²⁰

TurkeyIllegalCitation needed

Classified as a controlled drug.²¹²² Possession, production, supply, and importation are prohibited under Turkish drug law.

References

Source Pages

Citations

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4-AcO-DET

4-Acetoxy-N,N-diethyltryptamine

Ethacetin, Ethylacybin, 4-Acetoxy-DET

Psychoactive Class

Psychedelic

Chemical Class

Tryptamine