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4-AcO-MET
4-AcO-MET is a novel psychedelic substance of the tryptamine classcitation needed and the acetate ester of 4-HO-MET, for which it is theorized to serve as a prodrug. Structurally related to 4-AcO-DMT and other acetylated tryptamines, it produces psilocybin-like psychedelic effects. It has very little history of human use, and data regarding its pharmacology, metabolism, and toxicity remain limited. It is primarily available as a research chemical through online vendors.
Dosage & Duration
Dosage
Doses are population estimates that vary widely between individuals.
Threshold~5 mg
Light5-18 mg
Moderate18-25 mg
Strong25-40 mg
Heavy40+ mg
Duration
Onset20-40 minutes
Come Up30-60 minutes
Peak1-2 hours
Offset2-4 hours
After Effects2-12 hours
Total4-6 hours
Subjective Effects
Legacy content. A statistically backed ontology from Mindstate Design Labs is coming soon.
Effects vary widely by individual, dose, and context.
Physical
The physical effects of 4-AcO-MET can be broken down into three components all of which progressively intensify proportional to dosage.
Cognitive
The cognitive effects of 4-AcO-MET are described by many as somewhat relaxing, yet fast-paced in style with similarities to psychedelics such as LSD or 2C-B which tend to be cognitively energetic and stimulating.
Enhancement of current mind stateConnectivity of thoughtAcceleration of thoughtFeelings of fascination, importance and aweTime distortionOutrospectionThought loopsRemoval of cultural filterConceptual thinkingDirect communication with the subconsciousEgo suppression, loss and deathFeelings of interdependent oppositesDelusionsStates of unity and interconnectedness
Visual
Geometry
The visual geometry that is present throughout this trip can be described as somewhat similar in appearance to that of Psilocin, 4-AcO-DMT and 4-HO-MiPT but with far stronger synthetic digital undertones reminiscent of LSD or 2C-B. 4-AcO-MET can be comprehensively described through its variations as intricate in complexity, abstract in form, equally synthetic and organic in style, structured in organization, extremely brightly lit and multicoloured in scheme, glossy in shading, sharp in edges, large in size, fast in speed, smooth in motion, angular in corners, unimmersive in depth and consistent in intensity. The visuals have a contradictory 'natural' and 'synthetic' feel to them which is reminiscent of both LSD and Psilocybin. Higher dosages are significantly more likely to result in states of Level 8A visual geometry over Level 8B.
Hallucinatory States
4-AcO-MET and its various other forms produce a full range of high level hallucinatory states in a fashion that is more consistent and reproducible than that of many other commonly used psychedelics.
Auditory
The auditory effects of 4-AcO-MET are common in their occurrence and exhibit a full range of effects.
See also: Psychedelic Intensity Scale, Effects of psychedelics (visual, cognitive, miscellaneous)
Pharmacology
Pharmacodynamics
The psychedelic effects of 4-AcO-MET are believed to stem from its activity at the 5-HT2A receptorcitation needed, where it is thought to act as a partial agonist. 4-AcO-MET is the acetate ester of 4-HO-MET, and it is theorized to function as a prodrug that is converted to 4-HO-MET in the body, which would then mediate much of the pharmacological activity. Very little data exists about the detailed pharmacological properties of this substance, and the precise mechanisms by which its receptor interactions produce psychedelic effects remain unclear.
Pharmacokinetics
4-AcO-MET is hypothesized to be rapidly hydrolyzed into 4-HO-MET by serum esterases, in a manner analogous to how 4-AcO-DMT is thought to be deacetylated to psilocin (4-HO-DMT) during first-pass metabolism and subsequent hepatic processing. However, human studies confirming the metabolic fate of 4-AcO-MET are currently lacking.
Interactions
Interactions not written up yet
An unlisted combination is an unknown one, not a safe one. Check a dedicated combination chart before mixing.
Tolerance
Tolerance timelines are rules of thumb, not exact schedules, and vary widely between individuals and use patterns.
Full Tolerance
4-AcO-MET can produce tolerance very soon after it is taken. With consecutive-day use, users commonly need to double the dose each time to obtain comparable effects.
Baseline Reset
Approximately 7 days
Half Tolerance
Approximately 3 days
Cross Tolerance
Psychedelics (all serotonergic psychedelics will have reduced effects following 4-AcO-MET consumption)
Harm Potential
Addiction & Dependence
Psychological
Extremely Low4-AcO-MET is not regarded as habit-forming; with repeated use, the urge to take it may decline rather than build. Most users describe its use as self-limiting.
Physical
Extremely Low4-AcO-MET does not appear to produce physical dependence, with no documented withdrawal symptoms.
Psychosis Risk
Delusions are listed among possible cognitive effects during the acute experience. No specific data on psychosis incidence exists for this compound; standard psychedelic cautions apply regarding individuals with personal or family history of psychotic disorders.
Seizure Risk
No specific data on seizure risk exists for 4-AcO-MET.
History & Culture
4-AcO-MET, also known as metacetin, is a novel synthetic tryptamine that emerged primarily through the online research chemical market. As an acetate ester of 4-HO-MET and a structural homologue of 4-AcO-DMT, it represents one of many acetylated tryptamine derivatives that have been synthesized and…
Trip Reports
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Legality
By Country
Illegal1
United KingdomIllegal (analog/blanket ban)Misuse of Drugs Act 1971, Schedule 2, Part I, paragraphs 1(b) and 3; Misuse of Drugs Regulations 2001, Schedule 1, paragraphs 1(b) and 3; Misuse of Drugs Regulations (Northern Ireland) 2002, Schedule 1, paragraphs 1(b) and 3 (as substituted by S.R. 2015/53 and S.R. 2014/21)4567891011121314
4-AcO-MET is controlled throughout the United Kingdom as a Class A drug through the Misuse of Drugs Act 1971 structural generic and ester provisions, rather than by an individual 4-AcO-MET name entry. The Home Office has expressly identified 4-Acetoxy-N-methyl-N-ethyltryptamine (a verified synonym of 4-AcO-MET) and 4-hydroxy-N-methyl-N-ethyltryptamine (4-HO-MET) as Class A drugs under the generic tryptamine clause. The official chemical records show that 4-HO-MET is a ring-hydroxy tryptamine with methyl and ethyl groups on its side-chain nitrogen and that 4-AcO-MET is its 4-acetate ester. MDA Schedule 2 Part I paragraph 1(b)(i) captures the N-alkyl-substituted ring-hydroxy parent and paragraph 3 captures its ester. The corresponding generic and ester provisions place it in MDR Schedule 1 in England, Wales and Scotland and, through operative parallel amendments, in Schedule 1 in Northern Ireland. Home Office guidance describes the expanded-generic compounds as designated drugs without recognized medicinal or legitimate use outside licensed research. Unauthorized possession is unlawful under MDA section 5, subject to regulations and statutory defences. Coverage is structural/class-based despite its Class A legal classification.
Controlled / restricted2
Controlled under the Neue-psychoaktive-Stoffe-Gesetz (New Psychoactive Substances Act) as of July 18, 2019. Production, import with intent to market, administration to others, and trading are punishable offenses. Possession is illegal but not subject to criminal penalty. Ordering may potentially constitute incitement to place on the market.
Not scheduled1
United StatesNot scheduled4-AcO-MET is not expressly listed in the federal controlled-substance schedules current through August 27, 2026. FDA identifies the substance as 4-acetoxyethylmethyltryptamine (also 4-acetoxy-MET and metacetin; CAS 1445751-40-5; formula C15H20N2O2). Schedule I at 21 CFR § 1308.11(d) lists Psilocyn, and DEA/FDA identify Psilocyn as psilocin (4-hydroxy-N,N-dimethyltryptamine; formula C12H16N2O). Psilocin is therefore a Schedule I comparator, but this does not establish that 4-AcO-MET meets 21 U.S.C. § 802(32)'s substantial-similarity criteria. 4-AcO-MET has no substance-specific federal analogue determination. Under 21 U.S.C. § 813, a substance that first qualifies as a controlled substance analogue is treated as Schedule I to the extent intended for human consumption; intent alone does not establish analogue identity. This federal scheduling status is limited to direct federal scheduling, does not classify 4-AcO-MET as a controlled substance analogue, and does not determine state law or a transaction-specific prosecution.
References
Citations
- Anlage 1 NpSG. Bundesamt für Justiz (2026). https://www.gesetze-im-internet.de/npsg/anlage_1.html1
- National Center for Biotechnology Information. (2026). PubChem Compound Summary for CID 71308138, 4-Acetoxyethylmethyltryptamine. https://pubchem.ncbi.nlm.nih.gov/rest/pug/compound/cid/71308138/property/IUPACName,CanonicalSMILES,MolecularFormula/JSON1
- Verordnung des EDI über die Verzeichnisse der Betäubungsmittel, psychotropen Stoffe, Vorläuferstoffe und Hilfschemikalien (BetmVV-EDI). Eidgenössisches Departement des Innern (2026). https://www.fedlex.admin.ch/eli/cc/2011/363/de12
- Home Office: Annual report on the forensic early warning system (FEWS), 2020 to 2021. gov.uk (n.d.). https://www.gov.uk/government/publications/forensic-early-warning-system-fews-annual-report/annual-report-on-the-home-office-forensic-early-warning-system-fews-2020-to-20211
- PubChem CID 71308138 synonym record for 4-Acetoxyethylmethyltryptamine. pubchem.ncbi.nlm.nih.gov (n.d.). https://pubchem.ncbi.nlm.nih.gov/rest/pug/compound/cid/71308138/synonyms/JSON1
- PubChem CID 71308138 chemical-property record. pubchem.ncbi.nlm.nih.gov (n.d.). https://pubchem.ncbi.nlm.nih.gov/rest/pug/compound/cid/71308138/property/IUPACName,Title,MolecularFormula,ConnectivitySMILES,SMILES,InChI/JSON1
- PubChem CID 21786582 chemical-property record for 4-HO-MET. pubchem.ncbi.nlm.nih.gov (n.d.). https://pubchem.ncbi.nlm.nih.gov/rest/pug/compound/cid/21786582/property/IUPACName,Title,MolecularFormula,ConnectivitySMILES,SMILES,InChI/JSON1
- Misuse of Drugs Act 1971, Schedule 2 (latest available revised). legislation.gov.uk (n.d.). https://www.legislation.gov.uk/ukpga/1971/38/schedule/21
- Advisory Council on the Misuse of Drugs: Update of the Generic Definition for Tryptamines. assets.publishing.service.gov.uk (n.d.). https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/318693/UpdateGenericDefinitionTryptamines.pdf1
- Misuse of Drugs Regulations 2001, Schedule 1 (latest available revised). legislation.gov.uk (n.d.). https://www.legislation.gov.uk/uksi/2001/3998/schedule/11
Article Status
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Recent changes7 human edits · latest
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24 January 2026
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
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