What is HHC?

HHC, short for hexahydrocannabinol, is a cannabis-like drug, technically known as a semi‑synthetic cannabinoid. It emerged in Europe around 2021 – 2022 .

It is made by taking a legal part of the cannabis plant, called cannabidiol (CBD), and running it through a long manufacturing process. A series of chemical processes, first applied in the 1940s and 50s, which eventually turn CBD into HHC. It is made by taking THC, the part of cannabis plants that gets you high, from the CBD and adding a chemical element called hydrogen.

HHC can come as a flower/herb, as oil in vape cartridges, in disposable vapes or in edible form, such as gummies. It was previously sold in Ireland as a legal alternative to cannabis. On 29 July 2025, the Irish government announced that HHC was banned.

What are the short-term effects of HHC?

HHC has reported effects similar to cannabis. Though some initial studies suggest that it has a milder effect than cannabis, there are a lot of other factors that influence how drugs affect a person. HHC also has not been on the market for very long, meaning there is not a lot of research yet on how it affects people or how it affects people compared to cannabis.

Possible short-term effects of HHC include:

• Feeling in a good or relaxed mood
• Changes to perception, such as how time moves or how things taste, smell or feel
• Feeling more hungry, also known as the munchies
• Fatigue or sleepiness
• Dry mouth, sometimes known as cotton mouth
• Red or bloodshot eyes
• Dizziness
• Nausea or vomiting
• Anxiety and paranoia

According to research,  some of the most common reasons people report for using the drug are:

• For fun/to get high
• To reduce stress or relax
• To manage pain, depression, or anxiety
• To manage cannabis withdrawal symptoms

Negative side effects can happen at any dose, but are more likely if HHC is taken in higher doses.

What are the long-term effects of HHC?

Because it is relatively new, there is not as much available research about how it affects users long-term. This lack of information leads to uncertainty surrounding its safety and associated risks.

Health authorities such as the HSE are concerned that using HHC can lead to the development of psychosis. A study from the University Hospital Galway published in 2025 found that more than one-third of people admitted to the hospital for their first ever experience of psychosis had used the drug beforehand.

HHC was second to cannabis as the most commonly used substances among those with first-time psychosis between May 2023 and December 2024.

HHC and addiction

It is possible to become both psychologically and physically dependent on HHC. There have been cases of adolescents and young people entering addiction services due to HHC use and showing signs of withdrawal.

People who consume HHC regularly might find it difficult to cope without it and may end up self-medicating with it to deal with anxiety, insomnia, low mood and depression. Using a substance to cope with these kinds of feelings instead of addressing the root cause can negatively impact your mental health in the long term.

If you think you might be dependent on drugs, there are a number of services that can help. Find a service near you here or contact the Drugs Helpline on 1800 459 459 to find out about options in your area.

HHC and the law

HHC was previously available in some shops in Ireland. However its reported negative side effects prompted medical professionals to call for it to be banned.

The Irish government announced on 29 July 2025 that it had made HHC illegal. It is now a Schedule 1 controlled drug under the Misuse of Drugs Act 1977. This means that the import, export, production, possession, sale, and supply of products containing HHC is now against the law.

If you are caught with HHC, because you use it, or if you sell it, you could be arrested and charged with a crime. This could lead to being given a fine, sentenced to time in prison, or both. How harsh the punishment is depends on the type of crime committed, whether it is a first offence and more.

While HHC is now a controlled product, it may still be available on the black market. There are also products currently being sold as HHC alternatives in shops. The content of any of these kinds of products cannot be confirmed, so using them could carry significant risks.

Support services

• Health Research Board: Ireland’s Health Research Board keeps a services directory map on its website of national drugs and alcohol servicesOnline information and support for drug and alcohol use.
• HSE Drugs, Alcohol, HIV and Sexual Health Helpline: Freephone 1800 459 459.
• You can contact Youth Information Chat, an online service that can put you in touch with Youth Information Officers based all around the country, for more general information