A new report by the EMCDDA has highlighted the emergence of hexahydrocannabinol (HHC), a semi-synthetic cannabinoid (SSC) synthesized from cannabidiol (CBD) extracted from low-THC cannabis plants. Although HHC was first described in scientific literature in 1940, it was only identified in Europe in May 2022 and has since been monitored by the EU Early Warning System (EWS) as a new psychoactive substance (NPS). The purpose of the report is to raise awareness of the rapidly evolving market for HHC and related SSCs, and to provide an authoritative first overview of what is known so far.
Currently, there is limited knowledge of the effects and risks associated with using HHC. At the time of the report, HHC was not controlled in most European countries and is not scheduled under the 1961 and 1971 UN Conventions. Identifications of HHC had been reported by 20 EU Member States and Norway as of 31 March 2023.
Since HHC's detection in Europe, two other SSCs, HHC acetate (HHC-O) and hexahydrocannabiphorol (HHC-P), have been identified on the European drug market. These developments may indicate the first major change in the market for 'legal' replacements to cannabis since Spice-type products emerged in Europe 15 years ago.
Lab studies suggest that HHC has broadly similar effects to THC, the main psychoactive substance in cannabis. However, the pharmacological and behavioural effects of HHC in humans have not been studied, and recent anecdotal reports from consumers indicate that its effects might be similar to that of cannabis.
HHC is sold openly as a replacement for cannabis and THC products in a range of attractive branded and unbranded products. These include low-THC cannabis (hemp) flowers and resin, vape pens, e-liquids, e-liquid cartridges for use in e-cigarettes, edibles, and oils. Marketing and advertising often make comparisons to the effects of cannabis and THC.
Since October 2022, the EMCDDA has received reports of around 50 seizures of products containing HHC through the EWS, amounting to some 70 kg and almost 100 litres of material. While most of these were small-scale, three large seizures in Italy, Poland, and Germany suggest a potentially larger trade.
HHC may be used by existing cannabis users and new consumers attracted to its effects and legal status, including young and inexperienced people. Ease of access through high street CBD and vape shops may also promote use.
The arrival of HHC on the US drug market and other SSCs seems to be linked to legislative changes. The EMCDDA is taking several actions to respond to potential public health and social risks from this new market, including close monitoring, regular review of signals via the EWS, and technical expert meetings to support preparedness and response measures at the national and EU level.