11-OH-HHC.11-Hydroxy-hexahydrocannabinol

11-OH-HHC is the C11-hydroxylated metabolite of hexahydrocannabinol, with two epimers at C9, 9β (9R) and 9α (9S). In humans, it forms after HHC use and is then oxidised to HHC-COOH: after ingestion of 25 mg of HHC, it reached serum concentrations of the same order as HHC itself (Höfert et al., 2025), and it was present in all 16 urine samples from users in one series, almost entirely glucuronidated (Lindbom et al., 2025). It also derives, to a small extent, from Δ9-THC: it was detected in 15% of Δ9-THC-positive drivers in a series of 222 cases (Falck Jørgensen et al., 2023), so it cannot on its own prove HHC use. No receptor measurement has been published. In rats and pigeons trained to recognise Δ9-THC, the 9β epimer was several times more potent than Δ9-THC (about 17 times in pigeons), and more active than the 9α epimer (Järbe et al., 1986). In mice, the mixture of both epimers was almost as potent as Δ9-THC, whereas HHC was an order of magnitude less active (Skinner et al., 1979, as reported by the EMCDDA). In France it falls within the generic class of benzo[c]chromene derivatives; the UK ACMD recommended in May 2025 that it be listed by name in Class B.

Source

Metabolite: formed in mammals by hydroxylation of HHC at C11, and to a small extent from Δ9-THC; not described in the plant

No plant biosynthesis. In humans, HHC is hydroxylated at C11 to 11-OH-HHC, itself oxidised to the carboxylic acid (HHC-COOH) (Lindbom et al., 2025; Höfert et al., 2025). In human liver microsomes, 11-OH-HHC also forms from 11-OH-THC by reduction of the double bond; it was found in the blood of 15% of Δ9-THC-positive drivers in a series of 222 cases (Falck Jørgensen et al., 2023).

European Union

There is no European Union control measure targeting 11-OH-HHC by name; it is neither listed in the United Nations conventions nor subject to a specific European decision. It is its parent molecule that is regulated: HHC, the first semi-synthetic cannabinoid identified in Europe in 2022, was under control in at least 22 Member States in February 2025, and the United Nations Commission on Narcotic Drugs listed it in Schedule II of the 1971 Convention on Psychotropic Substances, a decision that came into force on 6 December 2025. The status of the metabolite therefore varies from country to country: it is captured in States that have a generic or analogue clause, such as France, and remains outside the scope in those that proceed by nominative lists. The European drugs agency (EUDA) monitors the whole family of semi-synthetic cannabinoids through the early warning system, forty of them having been identified on European markets by the end of 2025.

France

11-OH-HHC is not designated by name in the decree of 22 February 1990 establishing the list of substances classified as narcotics. It does, however, fall under a generic clause. The ANSM decision of 22 May 2024, which came into force on 3 June 2024, added to annex IV of that decree "any substance derived from the benzo[c]chromene nucleus, whether non-, partially or fully hydrogenated on ring A", substituted at position 1 by a hydroxyl function, at position 3 by an alkyl chain, at position 6 by one or two alkyl groups and at position 9 by a ketone, alkyl, hydroxyalkyl or alkoxy function, cannabinol excepted. 11-OH-HHC corresponds exactly to this description: fully hydrogenated benzo[c]chromene nucleus, hydroxyl at 1, pentyl at 3, dimethyl at 6 and hydroxymethyl at 9. Its status is therefore that of a substance captured by a generic clause, and not that of a named substance. It should be noted that the earlier clause covering "tetrahydrocannabinols, their esters, ethers, salts" does not apply here, the molecule not being a tetrahydrocannabinol. Its parent molecule, HHC, has for its part been explicitly classified as a narcotic in France since 13 June 2023, alongside HHC-acetate and HHCP. HHC has been listed in annex III of the decree since the ANSM decision of 16 January 2026. In practice, 11-OH-HHC is encountered almost exclusively as a metabolite in biological samples or as a laboratory standard, not as a marketed product.

Sources: EUR-Lex, UNODC, CND, ANSM, IUPHAR/BPS, ChEBI, EUDA. Our method.

Family

Metabolite

Chemistry

C5 side chain · neutral form

Parent molecule

HHC

Active metabolite.

Verification

Every fact on this entry was checked against its primary sources on 20 October 2026.

Wikipedia (English)

11-Hydroxyhexahydrocannabinol (new tab)

Article paired by the molecule's structure (InChIKey), revision read on 19 October 2026. Read as a second opinion, never cited as a source.

1. 1Falck Jørgensen C, Schou Rasmussen B, Linnet K, Thomsen R. Evidence of 11-Hydroxy-hexahydrocannabinol and 11-Nor-9-carboxy-hexahydrocannabinol as Novel Human Metabolites of Δ9-Tetrahydrocannabinol. Metabolites, 2023. (new tab)PMID 38132851
2. 2Höfert L, Franz B, Groß C, et al. Preliminary pharmacokinetic and psychophysical investigations after controlled oral and inhalative consumption of hexahydrocannabinol. Scientific Reports, 2025. (new tab)PMID 40128283
3. 3Lindbom K, Norman C, Baginski S, et al. Human metabolism of the semi-synthetic cannabinoids HHC, HHCP and their acetates. Drug Testing and Analysis, 2025. (new tab)PMID 38804224
4. 4Schirmer W, Auwärter V, Kaudewitz J, Schürch S, Weinmann W. Identification of human hexahydrocannabinol metabolites in urine. European Journal of Mass Spectrometry, 2023. (new tab)PMID 37709263
5. 5Di Trana A, Di Giorgi A, Sprega G, et al. Disposition of hexahydrocannabinol epimers and their metabolites in biological matrices. Pharmaceuticals, 2024. (new tab)PMID 38399464
6. 6Pettersson-Pablo P, Oxelbark J. LC-MS/MS analysis of 11-nor-9-carboxy-hexahydrocannabinol and 11-hydroxy-hexahydrocannabinol. Scandinavian Journal of Clinical and Laboratory Investigation, 2024. (new tab)PMID 38529884
7. 7Thomsen R, Axelsen TM, Løkken N, et al. Prolonged sedation and unconsciousness after intoxication with HHC-C8. Toxicology Reports, 2025. (new tab)PMID 39897393
8. 8Mechoulam R, et al. Stereochemical requirements for cannabinoid activity. Journal of Medicinal Chemistry, 1980. (new tab)PMID 7420350
9. 9Järbe TU, Hiltunen AJ, Lander N, Mechoulam R. Cannabimimetic activity of cannabidiol monomethyl ether and two stereoisomeric hexahydrocannabinols in rats and pigeons. Pharmacology Biochemistry and Behavior, 1986. (new tab)PMID 3020594
10. 10ANSM. Decision of 22/05/2024 amending the list of substances classified as narcotics (generic benzo[c]chromene clause, annex IV of the Order of 22 February 1990). (new tab)
11. 11ANSM. ANSM places hexahydrocannabinol (HHC) and two of its derivatives on the list of narcotics, 12 June 2023. (new tab)
12. 12ANSM. Decision of 16/01/2026 amending the list of substances classified as narcotics (HHC listed in annex III) (new tab)
13. 13EUDA. New psychoactive substances, the current situation in Europe, European Drug Report 2026. (new tab)
14. 14PubChem. 7-Hydroxyhexahydrocannabinol, CID 127684, National Library of Medicine. (new tab)

SMILES

CCCCCC1=CC(=C2[C@@H]3C[C@@H](CC[C@H]3C(OC2=C1)(C)C)CO)O

Machine-readable entry (JSON)

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