AM-855
Tetracyclic Δ8-THC analogue, a laboratory probe with no human data at all.
Harm-reduction warning
No characterised human dose: animal / in vitro data only. Effect profile, safety margin and acute toxicity are not documented in human clinical practice. Extremely potent compound: severe effects, seizures and deaths reported in the literature.
C₂₆H₃₈O₂
CID 10091328
- Family
- Synthetic CB receptor agonistResearch ligand or medicine
- Molar mass
- 382.60 g/mol
Updated on
In plain terms
AM-855 is a molecule made in the laboratory, found in no hemp plant. University chemists prepared it in 1999 to understand how cannabis receptors recognise the shape of the molecules that bind to them. It has never been studied in humans and goes into no product intended for consumption.
Receptors and activity
Target network
- Binds or modulates
The lower the cited value, the closer the target sits to AM-855: one ring per factor of 100. A target with no measured value stays on the edge.
Where these targets live
Where each target has been found in humans, according to the cited studies. The map shows the target, not an effect of AM-855.
CB1CB1 found in 7 regions of the body
- Basal gangliadenseMost dense in basal ganglia outflow nuclei1
- CerebellumdenseVery dense in the cerebellum1
- HippocampusdenseVery high concentrations in the hippocampus2
- AmygdaladenseHigh concentrations in the amygdala2
- CortexpresentPresent throughout the neocortex2
- Adipose tissuepresentExpressed in adipose tissue3
- GutpresentColonic epithelium, smooth muscle and plexus4
Map sources
- Herkenham M et al. Cannabinoid receptor localization in brain. Proc Natl Acad Sci U S A, 1990 (new tab)
- Glass M et al. Cannabinoid receptors in the human brain: a detailed anatomical and quantitative autoradiographic study in the fetal, neonatal and adult human brain. Neuroscience, 1997 (new tab)
- Engeli S et al. Activation of the peripheral endocannabinoid system in human obesity. Diabetes, 2005 (new tab)
- Wright K et al. Differential expression of cannabinoid receptors in the human colon: cannabinoids promote epithelial wound healing. Gastroenterology, 2005 (new tab)
Cited values
- CB1Binding (function not established)no measured value cited
binding at the CB1 receptor: the « southbound » conformer of the chain retains the highest affinity (Khanolkar 1999); the Ki value specific to AM-855 not verified in an open source
- CB2Binding (function not established)no measured value cited
binding at the CB2 receptor: same conclusion for the « southbound » conformer; Ki value specific to AM-855 not verified; efficacy not measured
Pharmacology
AM-855 belongs to the classical cannabinoids: its skeleton is that of Δ8-THC, to which a fourth ring has been added to lock the side chain in a single orientation. This locking was the very object of the study: by immobilising the chain, the authors sought to identify the geometry that the receptor actually recognises, and conclude that the “southbound” conformer of the chain is the one that retains the highest affinity for CB1 and CB2. Beyond this binding measurement, the literature consulted is silent: intrinsic efficacy was not measured, no in vivo study followed, and human data are entirely lacking. The fundamental difference from THC, which is only a partial agonist of CB1, is that it is not known whether AM-855 activates the receptor or merely binds to it: this question has not been settled.
Key sources.
- Khanolkar et al., Bioorganic and Medicinal Chemistry Letters, 1999: novel tetracyclic Δ8-tetrahydrocannabinol analogues with a conformationally restricted side chain (new tab)PMID 10465529
- ANSM, consolidated list of substances classified as narcotics, updated 16 February 2026: « any substance derived from the benzo[c]chromene nucleus » clause (annex IV) (new tab)
- INCB, Green List of psychotropic substances under international control, 35th edition, 2024 (Schedule II: AM-855 absent) (new tab)
- PubChem, AM-855, CID 10091328 (new tab)
History
- Source
- An entirely synthetic molecule. It exists neither in cannabis nor in any other plant: it was built in an academic laboratory from the classical cannabinoid skeleton, as a pharmacological probe (Khanolkar 1999). No use in a consumer product is reported in the sources consulted.
Origin
Laboratory synthesis
None. AM-855 has no biosynthetic pathway and no living organism produces it; it results from a chemical modification of the Δ8-THC skeleton carried out in the laboratory, the side chain being closed into an additional ring.
Legal framework
- European Union
No European Union text targets AM-855: it is not among the substances named in the annex of Framework Decision 2004/757/JHA as supplemented by Directives (EU) 2017/2103, 2019/369, 2020/1687, 2021/802, 2022/1326 and 2025/2062. It is likewise not listed in Schedule II of the 1971 Convention (Green List of the International Narcotics Control Board, 35th edition, 2024). Several Member States nevertheless apply generic definitions or analogue laws that may cover a derivative of this type without naming it.
- France
AM-855 is named neither in the consolidated list of ANSM (updated 16 February 2026) nor in any ANSM decision. The entry “Tetrahydrocannabinols, their esters, ethers, salts and the salts of the aforementioned derivatives” (annex III) does not obviously cover it: AM-855 is built on the Δ8-THC skeleton but is neither an ester, an ether nor a salt of THC. Annex IV also covers, since the decisions of 22 May and 3 June 2024, “any substance derived from the benzo[c]chromene nucleus” substituted notably at position 1 by a hydroxyl, at position 6 by one or two alkyl groups and at position 9 by an alkyl; AM-855 is a tetracyclic benzo[c]chromene whose chain at position 3 is closed into an extra ring, and the application of this clause to a structure whose position 3 is not a free chain is not established by the sources consulted. Its French status therefore remains to be confirmed. It has no authorisation as a food, cosmetic or supplement ingredient, which rules out its legal presence in a product sold to the public.
Sources: EUR-Lex, UNODC, CND, ANSM, IUPHAR/BPS, ChEBI, EUDA. Our method.
Classification
Family, origin and source verification
- Family
Synthetic CB receptor agonist › Research ligand or medicine
- Class
classical
- Verification
Classification, sources and binding values checked on 20 October 2026; text read against its sources and Wikipedia.
- Wikipedia (English)
Article paired by the molecule's structure (InChIKey), revision read on 19 October 2026. Read as a second opinion, never cited as a source.
References
- Khanolkar et al., Bioorganic and Medicinal Chemistry Letters, 1999: novel tetracyclic Δ8-tetrahydrocannabinol analogues with a conformationally restricted side chain (new tab)PMID 10465529
- ANSM, consolidated list of substances classified as narcotics, updated 16 February 2026: « any substance derived from the benzo[c]chromene nucleus » clause (annex IV) (new tab)
- INCB, Green List of psychotropic substances under international control, 35th edition, 2024 (Schedule II: AM-855 absent) (new tab)
- PubChem, AM-855, CID 10091328 (new tab)
Identifiers
Names
- IUPAC name
- (4aR,12bR)-8-hexyl-2,5,5-trimethyl-1,4,4a,8,9,10,11,12b-octahydronaphtho[3,2-c]isochromen-12-ol
- Other names
- AM855
Identifiers
- Formula
- C₂₆H₃₈O₂
- PubChem CID
- 10091328(new tab)
- InChIKey
- GAAJNVWIOIOMPO-IPKCRJEZSA-N
- SMILES
- CCCCCCC1CCCC2=
C(C3= C(C= C12) OC([C@H] 4[C@H] 3CC(= CC4) C) (C) C) O
LLM ingestion format: a structured superset of the entry (identifiers, binding, versioned legal status). Full corpus.