HHC (hexahydrocannabinol) is a semi-synthetic cannabinoid that is chemically close to THC and has similar intoxicating effects. It occurs in cannabis only in very low concentrations, so the HHC sold in vapes and other products is made in a laboratory, usually starting from CBD. In the UK, the government decided in 2025 to control HHC as a Class B drug; it is already covered by the Psychoactive Substances Act 2016.
Key facts
- Full name
- Hexahydrocannabinol, C21H32O2
- Type
- Semi-synthetic cannabinoid (SSC): a hydrogenated relative of THC
- In the plant
- Present naturally only in very low concentrations
- Effects
- Users report effects and adverse effects similar to THC; in animal models it is less to slightly less potent than THC
- UK status
- As of October 2026: not yet named in the Misuse of Drugs Act 1971, but psychoactive and therefore subject to the Psychoactive Substances Act 2016. The government accepted ACMD advice (August 2025) to make HHC a Class B drug.
- Europe
- First notified to the EU Early Warning System in October 2022; 108 detections in the UK in 2023
What is HHC?
HHC stands for hexahydrocannabinol. It belongs to a group the UK's Advisory Council on the Misuse of Drugs (ACMD) calls semi-synthetic cannabinoids: compounds made by chemically converting natural cannabinoids. HHC has been described as a phytocannabinoid because it is present in the cannabis plant, but only in very low concentrations (ACMD, 2025). Another example is delta-10 THC, which is also made from CBD.
Commercial HHC appeared on European markets in 2022. According to the ACMD, one driver was an oversupply of CBD, which made CBD a cheap starting material for producing other cannabinoids.
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How is HHC different from THC?
THC (tetrahydrocannabinol) has one double bond in its upper ring. HHC has hydrogen atoms in its place, which is what "hexahydro" refers to. This step, hydrogenation, produces a mixture of two forms: 9(R)-HHC and 9(S)-HHC. The 9(R) form is the more active one at the cannabinoid receptors.
| HHC | THC | |
|---|---|---|
| Formula | C21H32O2 | C21H30O2 |
| Origin of products | Made in a laboratory, often from CBD | Main natural cannabinoid of drug-type cannabis |
| Intoxicating | Yes | Yes |
| Potency in animal models | Less to slightly less potent than THC | Reference |
| UK status (October 2026) | Psychoactive Substances Act 2016; Class B control decided | Class B drug |
What does HHC do?
HHC acts on the CB1 receptor in the brain, like THC. In laboratory tests, 9(R)-HHC can activate CB1 as strongly as THC, but in animal models it is less to slightly less potent (ACMD, 2025). User reports describe effects and adverse effects similar to those of THC.
There are no controlled clinical trials of HHC. What is known comes from surveys and case reports:
- In an online survey of 109 people in the US who had used HHC, about 17% reported adverse effects, mostly sleepiness, red eyes, dry mouth and stomach problems, and about 20% of those who stopped reported withdrawal symptoms (Ferretti et al., 2024).
- A case report from Paris described a regular user who had seizures and lost consciousness after using an HHC vape (cited in ACMD, 2025).
Is HHC legal in the UK?
The legal position is changing. As of October 2026:
- Misuse of Drugs Act 1971: the Act's generic definition of controlled cannabinoids covers tetrahydro derivatives of cannabinol, but not hexahydro variants such as HHC (ACMD, 2025).
- Psychoactive Substances Act 2016: psychoactive compounds not caught by the 1971 Act, including HHC, are subject to the Psychoactive Substances Act, which makes producing and supplying them an offence (ACMD, 2025).
- Planned Class B control: in May 2025 the ACMD recommended naming HHC, HHCP, HHCH and related compounds as Class B drugs. The government accepted this on 20 August 2025 and confirmed on 11 May 2026 that it would proceed (Home Office, 2025 and 2026).
When we last checked legislation.gov.uk (8 October 2026), the amendment order naming HHC had not yet been published.
Other European countries have acted too. Sweden controlled HHC and HHCP in July 2023, after which uncontrolled analogues appeared on the market (ACMD, 2025).
What is HHC oil, and what forms is HHC sold in?
HHC has been sold in vape cartridges and liquids, as "HHC oil" in dropper bottles, in edibles and sprayed onto low-THC hemp flowers. These products are not CBD products, even when they are sold next to them. Their content is often unclear: semi-synthetic HHC is a mixture of the 9(R) and 9(S) forms, and the label rarely says in what ratio.
A related compound, HHCP (hexahydrocannabiphorol), has a longer side chain and is on the same list for Class B control.
Does HHC show up on a drug test?
It can. Swedish forensic laboratories found that cannabis screening tests cross-reacted with semi-synthetic cannabinoids, giving preliminary positive results that later proved to be HHC derivatives and other compounds rather than THC (ACMD, 2025). For CBD and testing, see CBD, drug tests and driving.
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 HHC weed?
"HHC weed" usually means low-THC hemp flowers sprayed with laboratory-made HHC. It is not natural cannabis, and the amount and purity of HHC on it are often unknown.
Is HHC natural or synthetic?
HHC occurs in the cannabis plant only in very low concentrations. The HHC in products is made in a laboratory by chemically converting other cannabinoids, often CBD, so it is classed as semi-synthetic.
Does HHC get you high?
Yes. HHC acts on the same CB1 receptor as THC, and users report effects similar to THC. In animal models it is less to slightly less potent than THC.
Is HHC legal in the UK?
As of October 2026, HHC is covered by the Psychoactive Substances Act 2016, which makes producing and supplying it an offence. The government has also decided to make HHC a Class B drug under the Misuse of Drugs Act 1971.
What is hexahydrocannabiphorol (HHCP)?
HHCP is the hexahydro form of THCP, with a seven-carbon side chain. Like HHC, it is semi-synthetic and on the list of compounds the UK government plans to control as Class B.
Does Formula Swiss sell HHC?
No. We don't sell HHC or any other intoxicating cannabinoid. Our CBD oils are sold as cosmetics for use on the skin.
Related guides
Formula Swiss does not sell HHC. Our CBD oils are sold as cosmetics for use on the skin and are not intended to diagnose, treat, cure or prevent any disease. This article is general information about the science and the law, not legal or medical advice.
Last reviewed:
Sources
- Advisory Council on the Misuse of Drugs (ACMD). Semi-synthetic cannabinoids: cannabinoids related to tetrahydro-cannabinol and cannabidiol. GOV.UK, May 2025.
- Home Office. Government response to the ACMD advice on semi-synthetic cannabinoids. 20 August 2025.
- Home Office. Further response to the ACMD advice on semi-synthetic cannabinoids. 11 May 2026.
- Ferretti ML, et al. A survey study of individuals using hexahydrocannabinol cannabis products: use patterns and perceived effects. Cannabis and Cannabinoid Research 2024. doi:10.1089/can.2023.0143
