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Hexahydrocannabinol (HHC) Category: Cannabinoids

About HHC

Hexahydrocannabinol (HHC) is a new product ‘cannabinoid’ product which has quickly emerged on the European and Irish markets since 2022.

It's currently available legally in high street shops but this does not guarantee safety and there are concerns regarding the health effects.

The word ‘cannabinoid’ refers to every chemical substance that joins the cannabinoid receptors of the body and brain and that have similar effects to those produced by the Cannabis Sativa plant. The cannabis plant has hundreds of chemicals with the most well-known being THC (controlled) and CBD. CBD is now commonly recognised as being sold in shops as this is a non-psychoactive chemical in cannabis. HHC has emerged as a man-made chemical (not natural/semi-synthetic form) developed from CBD.

New to the EU market

HHC was first identified in North America in 2021 and in Europe in May 2022 and is currently under intensive monitoring as a new psychoactive substance by the European Monitoring Centre for Drugs and Drug Addiction (EMCDDA) Early Warning System in order to better understand the potential risks to health.

The pharmacological and behavioural effects of HHC in humans have not been studied, though recent anecdotal reports show that its effects are similar to cannabis.

The information below is based on available evidence as well as emerging anecdotal evidence reported to the HSE in Ireland. This page may be subject to change over time as new evidence appears.


How it’s used

Short term effects

There is limited information available on HHC effects in humans, this is an evolving market that we continue to monitor in relation to evidence and anecdotal reports of the health effects.

Drugs can effect each person differently and there may be greater risks with HHC for young people and people with underlying health conditions.

The effects of any drug will depend on personal factors such as your physical and mental health as well as the dose and potency of a substance.

People who commonly consume cannabis should be mindful that you could react differently to different types of cannabinoids.

The overall effects of HHC can be similar to cannabis:


Long term effects

Psychosis risk

Emerging information from Irish hospitals has highlighted two case studies of regular cannabis smokers who experienced psychotic episodes as a posible result of vaping HHC. Psychosis can be short or longer term where people experience a series of symptoms where they lose touch with reality. Irish cases from HHC use have experienced extreme distress, delusions (beliefs), auditory hallucinations (hearing what is not there) paranoia, detachment from reality, self-harm, and

Other risks


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The HSE and Union of Students in Ireland (USI) ask students to think about drug safety measures when using club drugs
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