What is HHC: Origin, Effects, Risks and Why It Is Banned

09/22/2022 8 min read

What is HHC? Hexahydrocannabinol: Origin, Effects, Risks and Legal Status

What HHC is, how it is produced, what is known about its effects and risks, and why it is a banned psychotropic substance in the Czech Republic and other EU countries.

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 to Government Regulation No. 463/2013 Coll. Its production, sale, offering and possession without a licence are illegal. HHC is also banned in Germany, France, Poland, Slovakia, the Netherlands, Bulgaria and Romania, and it is a controlled substance in a number of other EU countries. HHC has not been approved as a medicine.

Cannabinoids are among the most studied substances found in cannabis. This article is about HHC, which is not actually a cannabinoid in the true sense of the word. You will learn what HHC is, how it is produced, what is known about its effects and risks, and why it is banned.

In today's article, you will learn

What is HHC? How is it created and how is it different?
Is HHC legal?
What is known about the effects and risks of HHC?
Why HHC is not a medicine

What is HHC? How is it produced and how is it different?

HHC is an abbreviation for hexahydrocannabinol. HHC occurs in cannabis plants only in very low amounts. Its extraction would thus be highly demanding and impractical. It is therefore a partially synthetic cannabinoid. This is a crucial difference from the more familiar THC or CBD, which are natural cannabinoids in the true sense of the word.

HHC was created in 1944 by American chemist Roger Adams when he added hydrogen molecules to Delta-9 THC. This process, known as hydrogenation, converted THC into hexahydrocannabinol (abbreviated as HHC).

The first HHC therefore originated from THC. In recent years, HHC has been made by chemically converting CBD obtained from cannabis with a low THC content.

CBD is extracted from raw hemp and distilled until the so-called CBD isolate is created. CBD crystals serve as the basis for the chemical reaction that produces HHC. The result is a semi-synthetic substance, not a natural hemp extract.

HHC Chemical Structure

HHC Chemical Structure

Is HHC legal?

HHC is not legal in the Czech Republic. It is classified as a psychotropic substance in Annex 4 to Government Regulation No. 463/2013 Coll. It may only be handled under a licence for research and scientific purposes, so its production and sale are illegal regardless of THC content or origin from industrial hemp. The same applies to the related substances HHCP, HHCH (HHC-C6), HHC-C8 and HHCB, which are listed psychoactive substances under Government Regulation No. 11/2025 Coll.

HHC is also banned in other European countries, for example in Germany, France, Poland, Slovakia, the Netherlands, Bulgaria and Romania. In a number of other EU countries, HHC is also a controlled substance.

What is known about the effects and risks of HHC?

HHC appeared on the market only recently and user experiences vary considerably. The effects of HHC have not been sufficiently studied, and HHC has not been approved as a medicine.

Available information shows that HHC is a psychoactive substance with effects similar to THC. According to some sources they are less strong, but reliable studies are lacking.

Reported adverse effects of HHC:

anxiety
dizziness
paranoia
insomnia
tachycardia - accelerated heart rate

Other risks:

unknown composition - unregulated products may contain a different amount of the substance than stated on the label
positive THC test - HHC can cause a positive drug test result
driving - it is not safe to drive under the influence of a psychoactive substance

HHC effects are comparable to THC in many ways. The safety of HHC has not been studied.

How long do HHC effects last?

We already know that HHC is similar to the cannabinoid THC in many ways. A certain similarity in the duration and intensity of effects can therefore be assumed.

Some people are extremely sensitive to THC and their metabolism breaks the substance down more slowly than in others. HHC effects can last from several dozen minutes to several hours, and their course is individual and hard to predict.

Why HHC is not a medicine

HHC has not been approved as a medicine, and there is not enough evidence of its effectiveness or safety. It therefore cannot be recommended for any health condition. HHC products were not controlled like medicines, and their composition could differ from what the label stated.

If you have health problems, consult a doctor.