HHC: Rare Cannabinoid, History, Risks and Legal Status

10/07/2022 Author: Martina 7 min read

HHC: A Rare Cannabinoid, Its History and Legal Status

Introduction to a not entirely known cannabinoid HHC. It can be found naturally in the cannabis plant, yet was discovered as a result of a chemical process. Its effects are similar to the most well-known psychotropic cannabinoid THC, but to a lesser degree. And you can read more in the article.

Legal status of cannabis in the European Union (as of 25 September 2026)

The EU has no single cannabis law: it sets a common framework for hemp farming, trade and drug trafficking, while recreational use is regulated by each Member State.
CBD lawfully produced in one Member State may in principle be sold in another; a national ban is allowed only if it is suitable to protect public health and does not go beyond what is necessary. The Court held that such CBD is not a narcotic drug under the 1961 Single Convention (Articles 34 and 36 TFEU, Case C-663/18 Kanavape, paras 76 and 96).
Industrial hemp qualifies for CAP direct payments only if the THC content of the variety does not exceed 0.3 % (Art. 4(4) Regulation (EU) 2021/2115); THC control methods are set by the Commission (Art. 60(4)(a) Regulation (EU) 2021/2116).
Member States may restrict how hemp is grown, for example ban indoor hydroponic cultivation, if the restriction is suitable and proportionate for protecting public health (Case C-793/22 Biohemp Concept, 4 October 2024).
Member States must make intentional unlawful cultivation of cannabis plants and drug trafficking a criminal offence (Art. 2(1)(b) Framework Decision 2004/757/JHA, as quoted in Case C-271/23).
Rules on recreational cannabis differ widely: Germany allows adults to possess up to 25 g in public, 50 g at home and three plants (§ 3 and § 9 KCanG), while in Czechia personal use becomes a criminal offence only above 5 plants, 200 g at home or 50 g elsewhere, and plants with up to 1 % THC are excluded (§ 285 Czech Criminal Code).

“Články 34 a 36 SFEU musí být vykládány v tom smyslu, že brání vnitrostátní právní úpravě, která zakazuje uvádět na trh CBD, který je legálně vyprodukován v jiném členském státě, v případě, že je extrahován z celé rostliny cannabis sativa, a nikoli pouze z jejích vláken a semen, ledaže je tato právní úprava s to zaručit naplnění cíle ochrany veřejného zdraví a nepřekračuje meze toho, co je k dosažení tohoto cíle nezbytné.”
[Translation: “Articles 34 and 36 TFEU must be interpreted as precluding national legislation which prohibits the marketing of CBD lawfully produced in another Member State when it is extracted from the Cannabis sativa plant in its entirety and not solely from its fibre and seeds, unless that legislation is appropriate for securing the attainment of the objective of protecting public health and does not go beyond what is necessary for that purpose.”]
Court of Justice of the European Union, 19 November 2020, Case C-663/18 (Kanavape)

This overview is based on legislation and case law in the legal database Europaius. It is not legal advice.

Legal status: In the Czech Republic, HHC (hexahydrocannabinol) is a psychotropic substance listed in Annex 4 of nařízení vlády č. 463/2013 Sb. Producing, selling, offering and possessing it without a licence is illegal. Related substances such as HHCP, HHC-C8 or HHCB are banned under nařízení vlády č. 11/2025 Sb. In a number of other EU countries, HHC is also a controlled substance.

Perhaps you haven't heard about HHC yet. One of the reasons is that it is a less common cannabinoid in hemp, and thus fewer studies focus on it. In this article, we introduce it, explain how it is made and why it is regulated.

What is the HHC cannabinoid?

Although HHC as a cannabinoid has been known since 1944, it's not widely discussed. It is hexahydrocannabinol, first produced by the American chemist Roger Adams. Adams added hydrogen to delta-9 THC. This hydrogenation process transformed THC into HHC. Products with HHC that appeared on the market are mostly made semi-synthetically from CBD extracted from hemp, which means their composition depends on the chemical process used.

HHC vs. THC - What's the Difference?

Although HHC originated from THC, how do these two cannabinoids differ? The fundamental difference is the added hydrogen, which changes the structure of the molecule. HHC is also considered somewhat weaker than THC, but it is still psychoactive, with effects similar to delta-9 THC.

HHC Compound

Chemical Compound of HHC Cannabinoid

Because of its psychoactive effects similar to THC, HHC has been placed under control in the Czech Republic and in a number of other European countries.

What Effects Does HHC Cause?

HHC consists of two types of molecules. The first is 9R HHC, which binds to endocannabinoid receptors more readily, and the second is 9S HHC, which has a different structure and binds to receptors less easily. The ratio of the two varies from product to product, so the effects are hard to predict. HHC binds to CB1 receptors in the brain and causes psychoactive effects similar to THC.

Further research on HHC cannabinoid is necessary

Since HHC is not yet as extensively studied as other cannabinoids, experts in their claims warn about potential negative side effects, such as dizziness, risks of mental disorders, higher injury risks, and others.

Is HHC Treatment Possible?

HHC has not been approved as a medicine, and its effects and safety have not been sufficiently researched. There are no reliable data showing that HHC could treat any disease. Known risks include:

Psychoactive effects similar to THC, including dizziness, anxiety and impaired concentration
Unknown composition of uncontrolled products, which may contain residues from the production process
A positive THC test, as HHC metabolites can be detected in drug tests
Impaired ability to drive after use

HHC remains a subject of research, but for now the available information is limited, and in the Czech Republic and other EU countries it is treated as a controlled substance.