THCH (Δ9-tetrahydrocannabihexol) is a close relative of THC with a six-carbon side chain instead of five. Italian researchers identified it in a medical cannabis variety in 2020. Products sold as THCH are made by chemical synthesis. In lab tests it activated the CB1 receptor more strongly than THC, and in the UK it is a Class B drug.
Key facts
- What it is
- The hexyl (6-carbon) homologue of Δ9-THC
- In the plant
- Identified in the FM2 medical cannabis variety (2020); commercial THCH is synthesised
- CB1 activity (lab)
- Higher potential for CB1 activation than Δ9-THC in a cell assay
- Human studies
- None published (as of October 2026)
- UK legal status
- Class B: 3-alkyl homologues of THC count as cannabinol derivatives (as of October 2026)
What is THCH?
THC belongs to a family of homologues: molecules that differ only in the length of their alkyl side chain. Δ9-THC has five carbons in that chain. THCB has four, THCP has seven, and THCH sits between them with six.
In 2020, Italian researchers identified the hexyl homologues of CBD and THC in the FM2 medical cannabis variety and named them cannabidihexol (CBDH) and Δ9-tetrahydrocannabihexol (Δ9-THCH). They confirmed THCH by comparing it with a synthetic standard and gave a semi-quantitative estimate of how much the variety contained (Linciano et al., 2020).
Is THCH natural or synthetic?
Both, in a sense. It has been found in cannabis, but THCH sold in shops is made in the lab.
Researchers place it among the semi-synthetic and synthetic THC variants that appeared in unregulated markets as alternatives to THC (Janssens et al., 2024). Labels are not reliable: one Japanese study found THCH acetate in a vape liquid labelled as containing a different cannabinoid altogether (Watanabe et al., 2025).
Is THCH stronger than THC?
Lab results suggest it may be, but there are no human studies. In a cell assay of 30 THC variants, THCH was one of several homologues and analogues that showed a higher potential to activate the CB1 receptor than Δ9-THC (Janssens et al., 2024). CB1 is the receptor behind the THC high.
A 2026 mouse study compared THCH with THC, HHC and other new cannabinoids. It measured how much of each compound reduced movement and how much caused catalepsy-like immobility, as an index of toxic motor effects (Shirakura et al., 2026). Studies like this help toxicologists rank risks. They do not show what a dose does in people.
THCH vs THC vs THCP: how do they compare?
| Feature | Δ9-THC | THCH | THCP |
|---|---|---|---|
| Side chain | 5 carbons (pentyl) | 6 carbons (hexyl) | 7 carbons (heptyl) |
| In cannabis | Main intoxicating cannabinoid | Minor; identified in 2020 | Minor; identified in 2019 |
| CB1 activation (cell assay) | Reference | Higher potential than Δ9-THC | Higher potential than Δ9-THC |
| UK status | Class B | Class B | Class B |
Sources for the table: Linciano et al., 2020; Citti et al., 2019; Janssens et al., 2024; Misuse of Drugs Act 1971, Schedule 2.
Does THCH show up on a drug test?
It may. In human liver enzyme tests, THCH produced hydroxylated and carboxylated metabolites similar to those of THC (James et al., 2026). Whether a standard workplace screen detects them depends on the test. Read our guide on drug tests and driving.
Is THCH legal in the UK?
No. The Misuse of Drugs Act 1971 makes cannabinol derivatives Class B drugs and defines them as "tetrahydro derivatives of cannabinol and 3-alkyl homologues of cannabinol or of its tetrahydro derivatives". THCH is a 3-alkyl homologue of THC, so it falls under that definition. The Home Office confirms that cannabinol derivatives, including THC, are Class B drugs, while pure CBD is not controlled (Home Office, 2024).
From our production
We don't sell HHC or any other cannabinoid that intoxicates, and we don't sell THCA products that turn into THC when heated.
— Robin Roy Krigslund-Hansen, co-founder and CEO
Frequently asked questions
What is THCH?
THCH (Δ9-tetrahydrocannabihexol) is a THC homologue with a six-carbon side chain. It has been identified in a medical cannabis variety, and products containing it are made by synthesis.
Is THCH psychoactive?
Probably, but it has not been tested in people. In a cell assay it showed a higher potential to activate the CB1 receptor, the receptor behind the THC high, than Δ9-THC.
Who discovered THCH?
An Italian research team reported Δ9-THCH and its CBD counterpart, cannabidihexol, in the FM2 medical cannabis variety in 2020.
Is THCH legal in the UK?
No. As a 3-alkyl homologue of THC, it counts as a cannabinol derivative under the Misuse of Drugs Act 1971 and is a Class B drug.
Can THCH products be trusted?
Be careful. Researchers have found vape liquids whose contents did not match the label, including one containing THCH acetate that was not declared.
Related guides
This article summarises published research. It is not medical advice. Formula Swiss CBD oils are sold as cosmetics for use on the skin. They are not food supplements or medicines and are not intended to diagnose, treat, cure or prevent any disease.
Last reviewed:
Sources
- Linciano P, Citti C, Russo F, et al. Identification of a new cannabidiol n-hexyl homolog in a medicinal cannabis variety with an antinociceptive activity in mice: cannabidihexol. Sci Rep 2020;10(1):22019. doi:10.1038/s41598-020-79042-2
- Citti C, Linciano P, Russo F, et al. A novel phytocannabinoid isolated from Cannabis sativa L. with an in vivo cannabimimetic activity higher than Δ9-tetrahydrocannabinol: Δ9-tetrahydrocannabiphorol. Sci Rep 2019;9(1):20335. doi:10.1038/s41598-019-56785-1
- Janssens LK, Van Uytfanghe K, Williams JB, et al. Investigation of the intrinsic cannabinoid activity of hemp-derived and semisynthetic cannabinoids with β-arrestin2 recruitment assays, and how this matters for the harm potential of seized drugs. Arch Toxicol 2024;98(8):2619–2630. doi:10.1007/s00204-024-03769-4
- Watanabe S, Murakami T, Muratsu S, et al. Discrepancies between the stated contents and analytical findings for electronic cigarette liquid products: identification of the new cannabinoid, Δ9-tetrahydrocannabihexol acetate. Drug Test Anal 2025;17(5):694–700. doi:10.1002/dta.3777
- Shirakura S, Ohta A, Abe H, et al. Emerging cannabinoids differ in behavioral safety margins in mice: a comparative hazard proximity analysis of locomotor suppression and catalepsy-like immobility. Forensic Toxicol 2026. doi:10.1007/s11419-026-00786-z
- James KM, Poklis JL, Karschner EL, Dempsey SK, Peace MR. Delta-9-tetrahydrocannabutol, delta-9-tetrahydrocannabihexol, and delta-9-tetrahydrocannabiphorol: the impact of varying alkyl chain length on delta-9-tetrahydrocannabinol analog metabolism. J Anal Toxicol 2026;50(8):bkag045. doi:10.1093/jat/bkag045
- Home Office. Drug licensing factsheet: cannabis, CBD and other cannabinoids (updated 3 October 2024). gov.uk
- Misuse of Drugs Act 1971, Schedule 2. legislation.gov.uk
