The lucrative and unregulated market of semi-synthetic cannabinoids is rapidly expanding across Europe, raising public health concerns and posing a legislative challenge to policymakers. The solution lies not in prohibition but in regulation.
According to Hungarian media reports, 31 foreign tourists were hospitalised with severe intoxication symptoms in Budapest during the last week of June 2024. Most of these patients were reported to be in a critical, comatose condition. Some spent several days in the toxicology department of a Budapest hospital before recovering. One Jordanian couple was found lying on the floor of their Airbnb apartment, amidst their own faeces, after disappearing for days.
Some patients had gummies in their pockets that could be traced back to the Cannabis World Budapest store on Váci Street, the most prominent shopping street in a touristy area of Budapest. According to the packaging, these gummies contained THC-JD, a legal psychoactive substance similar to the illegal delta-9-THC, the main psychoactive constituent of the cannabis plant. One pack contained five gummies with 25 mg of THC-JD each, totalling 125 mg per pack.
Although THC-JD is not listed as a controlled substance in Hungary, its sale may be interpreted as “incitement to the use of narcotics”, an offence under Hungarian criminal law. Consequently, the Budapest police seized all the gummies in the shop and opened a criminal investigation. The gummies were sent to the laboratory of the Hungarian Institute for Forensic Sciences (NSZKK) for analysis. The results have not yet been published. According to the National Drug Focal Point, a report was sent to the European Drug Agency (EUDA), a Lisbon-based EU agency responsible for monitoring the drug situation in Europe.
This is not an isolated incident. Similar media reports have emerged in other countries recently. For example, dozens of children were hospitalised in the Czech Republic, Slovakia and Bulgaria after consuming delicacies filled with semi-synthetic cannabinoids such as HHC or THCP. According to a technical report published by EUDA, the market for semi-synthetic cannabinoids is “rapidly evolving” in Europe, and “retailers can be found in, or ship to, most EU Member States”, offering various forms of edible and smokable products, including candies, biscuits and disposable vapes sold in vending machines alongside nicotine-containing vaping products. Although distributors claim to sell completely legal, “safe” and “tested” products, there is no regulation, quality control or consumer protection. These products are easily accessible to both adults and children alike.
What are semi-synthetic cannabinoids?
THC-JD is just one of many products sold as “legal highs” in the emerging grey market of semi-synthetic cannabinoids. Although the EUDA classifies them as new psychoactive substances (NPS), most of these drugs are not new, they have been known for decades, at least among chemists. Distributors claim that these substances can be found naturally in trace amounts in the cannabis plant itself, making them “natural”. However, even if they naturally occur in cannabis, their quantity is too small to extract directly from the plant. Therefore, they are produced by converting CBD or other cannabinoids in the laboratory, which is why they are called semi-synthetic substances.
The market for semi-synthetic cannabinoids is rapidly changing as legislators try to catch up with producers and distributors, who are always ready to launch chemical substitutes whenever a cannabinoid is added to the list of illicit substances in a country. Sometimes, the differences between these substances in their chemical structure are very minor: an extra hydrogen atom here, an extra carbon atom there. However, these apparently small chemical differences can significantly alter how they bond to the cannabinoid (CB1 and CB2) receptors in the human neural system, thus changing their psychoactive effects. For example, size matters; a longer carbon chain means stronger effects. Drug designers are aware of this when they create new substances.
Let’s look at a few examples (the list is not comprehensive):
Delta-8-THC is an isomer of delta-9-THC, with which it co-occurs in hemp, although in very low quantities. Delta-8-THC and delta-10-THC, which also appeared on the market, are reported to have milder psychoactive effects than delta-9-THC.
HHC (hexahydrocannabinol) is very similar to delta-9-THC but with an extra hydrogen atom. It has been known among chemists since 1940, but its large-scale production and distribution only started in 2022. Its effects are reported to be quite similar to those of natural THC. It is now banned in several countries, including Hungary.
THC-JD (tetrahydrocannabioctyl, Delta-9-THC-C8) has a very similar molecular structure to Delta-9-THC but with a longer alkyl side chain, containing eight carbon atoms instead of five. It gained popularity in Hungary after one of its predecessors, HHC, was banned in 2023 (and is still legal in other EU member states at the time of this article’s publication).
THC-P (Delta-9-THC-C7) has a side chain with seven carbon atoms. According to a 2019 study published in Scientific Reports, it has 30 times stronger receptor binding affinity compared to regular THC.
THC-H (Delta-9-THC-C6), also known as tetrahydrocannabihexol, contains six carbon atoms in the side chain. Again, it has stronger effects than regular THC.
THC-O (THC-O-acetate) is created from delta-8-THC or delta-9-THC through acetylation, a process that results in higher-potency substances. Distributors and proponents claim that THC-O-acetate has “hallucinogenic” effects. However, according to a 2023 study published in the Journal of Psychoactive Drugs, these claims are probably exaggerated.
Why is this market emerging now?
If these substances have been known since the 1940s, why did mass production and distribution only emerge a few years ago? The answer lies in a loophole created by the Farm Act of 2018 in the US. This law made it legal to produce and distribute “all derivatives” of the hemp plant “whether growing or not”, provided they contain less than 0.3% delta-9-THC. The law is intended to legalise the sale of CBD (cannabidiol), a non-psychoactive but medically useful compound found in the hemp plant. However, hemp companies overestimated the demand for CBD products, and when they produced a huge surplus of CBD, they decided to convert it to other semi-synthetic (and very psychoactive) cannabinoids.
Products containing these semi-synthetic cannabinoids were imported to the European market in large quantities in multiple forms: edible, liquid, smokable and vaping. The new boom started with delta-8-THC in 2019, followed by HHC and other substances. Although member states responded with repressive measures, such as bringing new substances under control, this only resulted in replacements and further proliferation. According to a 2024 study, it is likely that several substances are now produced not from cannabinoids extracted from the hemp plant but from synthetic analogues.
Uncertain risks in a grey market
There is very limited research evidence available about the psychoactive effects of semi-synthetic cannabinoids, not to mention the risks of their use to public health. Some decision-makers may interpret recent hospitalisations as a clear sign that these substances are dangerous—much more dangerous than the natural cannabis plant. Indeed, these substances seem to have a stronger potency than naturally occurring delta-9-THC. However, these accidental overdoses and hospitalisations do not prove the high substance-specific risks of semi-synthetic cannabinoids but rather the high risks associated with the unregulated market. In an unregulated market, edible products containing delta-9-THC can also cause massive accidental overdoses.
Many victims of accidental overdoses were children because these products are easily accessible to people under 18 years old through online shops and vending machines. Their deceptive, colourful packaging not only attracts children’s attention but is not clearly distinguishable from regular gummies and candies. Some of the edible products contain a massive amount of psychoactive ingredients and can thus be easily overdosed by adults who are not educated about the risks, as happened with the THC-JD gummies in Hungary.
Moreover, there is absolutely no quality control; we do not know how these products are produced, processed, stored, dosed or packaged. We have reason to believe that many products sold in this market may contain psychoactive ingredients in higher doses than indicated on the package, as well as other substances not listed in the ingredients. For example, CBD-derived cannabinoid products frequently include Delta-9-THC as a reaction side product (often at levels exceeding what is legally permissible in hemp products). It is also possible that some products contain undisclosed and unidentified fully synthetic cannabinoids, as well as non-cannabinoid side products and contaminants. One example is ketene, a gas that can be formed when THC-O is exposed to vaporisation temperatures, as demonstrated by a 2023 study. Inhaling ketene was associated with the outbreak of the e-cigarette product use–associated lung injury epidemic in 2019.
Policy responses doomed to fail
Most EU institutions and member states responded to the emergence of this highly volatile new grey market with the traditional prohibitionist approach. The so-called Early Warning Systems in each member state send warnings and alerts to the EUDA (formerly EMCDDA) about new substances and related health emergencies. Risk assessment reports are created, but these reports are usually based on very limited evidence and can only indicate the presence of risks without specifying whether these risks are substance-specific or associated with the uncontrolled market. The only response from governments is to add new substances to the schedules of controlled substances, effectively banning all non-scientific and non-medical use and distribution.
This chain of reactions creates the comforting illusion that the EU is taking rapid action to protect the health and well-being of its citizens. In reality, it only stimulates producers and distributors to invent and launch ever-new psychoactive substances onto the market. Furthermore, it creates increasing uncertainty and confusion even among professionals and researchers about the current situation in the drug markets, not to mention the general population.
EUDA, the EU’s drug agency, is doing valuable work to produce up-to-date and reliable knowledge about drug markets. However, what is painfully missing is an analysis of the impact of policies. This is a contentious issue that both EU institutions and most member states avoid addressing, as it would lead to politically sensitive conclusions about the overall effectiveness of repressive, tough-on-drugs policies that are difficult to present to the public. Even countries that have decided to regulate the cannabis market, such as Germany, have no real solution to the emergence of semi-synthetic cannabinoids. Many claim that regulating cannabis will automatically resolve this problem, but as we can see in North America, these hopes may prove ill-founded.
To dare to think outside the box: The Czech solution
There is only one EU member state that dares to challenge the prohibitionist consensus: the Czech Republic. Its energetic national drug coordinator, Jindrich Voboril (watch our interview with him on Drugreporter), proposed an unorthodox solution to the problem and designed a law to regulate semi-synthetic cannabinoid. This law, described as revolutionary by some, will supplement another legislative reform to regulate the cannabis market in the Czech Republic and is now awaiting approval from the EU Commission. It has already passed the lower house of the Czech parliament. This is the first effort by a nation-state to create a regulatory system for cannabinoids after the failed legislative initiative in New Zealand (watch our movie, A Foot in the Door: A New Approach to Drugs in New Zealand).
According to the new regulation, any company dealing with psychoactive (or “psychomodulating”, as the law describes them) substances must register with a government office responsible for controlling the market. Only substances “with psychoactive effects that represent a low risk of negative health or social impacts on individuals and society” can be legally distributed. Producers must submit convincing research evidence that their products comply with these requirements. Production, manufacturing, processing, storing, packaging and all other activities related to these products are strictly regulated by the government agency. Registered manufacturers and distributors must comply with several requirements, such as proving that the product they intend to sell contains no more psychoactive ingredient than allowed, labelling with all relevant information and safety warnings about the product, and ensuring packaging is not deceptive and does not resemble food or cosmetic products.
This approach is truly revolutionary but does not venture into completely uncharted territory: governments have extensive experience regulating risky behaviours and substances, including alcohol and tobacco. We know how to control and limit access to risky substances without resorting to either free commercialisation or massive criminalisation. The benefit of regulation compared to prohibition is that it offers much more flexibility to adapt to changing circumstances. If the law is adopted, it will hopefully push EU institutions and other member states out of their comfort zones to explore new regulatory mechanisms. Because one thing is certain: what we are doing today does not work and creates more harm than good.