EU Drug Market: New psychoactive substances — Distribution and supply in Europe: Synthetic cathinones

This resource is part of EU Drug Market: New psychoactive substances — In-depth analysis by the EMCDDA and Europol.

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Last update: 27 June 2024

Background

Synthetic cathinones first appeared on the European fdrug market in 2004. Since then, they have been sold as replacements for controlled stimulants such as amphetamines, cocaine and MDMA. They are also mis-sold as these controlled stimulants to unsuspecting consumers.

Typically, they are found as powders and, to a lesser degree, tablets. In the latter case, these may be mis-sold as or used to adulterate MDMA (ecstasy) tablets. Other physical forms are reported to a much smaller degree.

The cathinones are used recreationally, but they are also used by high-risk drug users in some countries, including by people who inject stimulants and opioids. This also includes in the context of chemsex. In some cases, changes in patterns of use, such as an increase in injecting frequency with cathinones, have been linked to HIV and HCV outbreaks.

There are some indications that certain cathinones, such as 4-MMC (mephedrone), 4-CMC (clephedrone) and 3-CMC (clophedrone), may be becoming more established in Europe, in part due to domestic production that takes place mainly in the Netherlands and Poland.

Production

Until around 2019, most bulk quantities of synthetic cathinones seized at the external EU borders originated in China. However, since then, production has also spread to India, where these substances are apparently produced on a large scale. In addition, the production of synthetic cathinones continues to grow in parts of Europe.

At least 68 illicit laboratories dismantled in Europe since 2013 were producing cathinones. Of these, the majority (47 sites, 69 %) were dismantled between 2017 and 2021. During that period, dismantled production facilities were reported by Poland (36 sites, 77 %), the Netherlands (8 sites, 17 %) and France, Slovakia and Spain (one site each). The majority of sites produced 4-MMC (23 sites, 49 %) and 4-CMC (17 sites, 36 %), both of which are substances under international control, since 2015 and 2020, respectively (see Figure Dismantled laboratories associated with cathinone production in Europe by substance produced, 2017-2021).

Preliminary information from the Polish Police suggests that the production of cathinones in Poland has continued to be significant in 2022 and 2023, with 17 laboratories dismantled in 2022 and 16 in the first six months of 2023. The latter has resulted in seizures of cathinones that may amount to 10 tonnes of (wet) cathinones, mostly 4-MMC, 4-CMC and 3-CMC (Polish Police Central Bureau of Investigation, personal communication). In the Netherlands, four laboratories were seized in 2022 and at least two in 2023, all of which were manufacturing 4-CMC, 3-CMC or both. It was reported that Polish individuals were alleged to have been involved in the laboratories found in the Netherlands.

In Europe, the size and scale of cathinone laboratories varies from ‘kitchen-scale’ production sites in basements and family dwellings (Wojciech, 2022; Wrzesień et al., 2018), to higher throughput facilities operated by multiple ‘cooks’ producing several dozens of kilograms of finished product per batch in special reactors (Wojciech, 2022). In the smaller sites, production appears to be destined mostly for local markets and, occasionally, for sale on the darknet. Although information is very limited, larger production sites also appear to supply local markets and occasionally the finished product is exported outside Europe (see Box Dismantled 4-MMC laboratory in Austria, 2021).

Cathinone production does not require sophisticated equipment. Nonetheless, production appears to be getting more industrialised and efficient. In Poland, basic laboratory glassware has been gradually replaced by large plastic reactors with cooling, heating and mixing systems and temperature control. This demonstrates some interest in improving production efficiency, since heating or mixing are not required to synthesise most cathinones, but their use increases reaction speed and yields. In several dismantled laboratories, the producers alternated between the production of different cathinones (e.g. 4-MMC and 4-CMC), using the same equipment and only varying some of the chemicals used (Wojciech, 2022).

Cathinone synthesis and precursor seizures

The production of synthetic cathinones is a relatively straightforward process. Although, in theory, several synthetic approaches may be used, the method encountered in European production facilities is a two-step procedure sometimes called ‘bromination-amination’ (EMCDDA, 2022c; Europol, 2019) (see Figure Bromination-amination method for the preparation of ring-substituted cathinones).

Note: For 4-MMC (mephedrone) R₁ = p-CH₃; R₂ = CH₃; R₃ = CH₃. Step 1 – preparation of 2-bromo-4-methylpropiophenone; step 2 – preparation of 4-MMC by amination with methylamine.

The first step (bromination) consists of adding bromine to a suitable ’propiophenone‘ (I) to produce a ‘bromopropiophenone’ intermediary (II). The bromine required for this step can be commercially obtained as a liquid or prepared in the clandestine facility. This is by far the most challenging and hazardous step of the process, given the high toxicity and corrosive properties of bromine.

In the second step (amination), an amine is added to the ‘bromopropiophenone’ intermediary (II) to produce the final cathinone. This amine can be changed according to the desired product. For example, methylamine is the compound of choice for the production of mephedrone or clephedrone. Methylamine is also commonly used in the production of methamphetamine and MDMA.

The amination step does not require heating and can be easily scaled up, making it a relatively simple procedure to execute. This synthesis produces the desired products as racemic mixtures. Finally, the resulting base products are converted into salts (typically hydrochloride salts) and then recrystallised to remove impurities in the large plastic trays that are characteristic findings in cathinone production facilities (see Photos Dismantled site associated with 4-CMC production in Poland, seized in 2022 with approximately 2 400 litres of 4-CMC seized) (Wojciech, 2022).

The preparation of cathinones using this method is an industrially efficient process for two reasons. First, because bromopropiophenones are commercially available in several variations and are not subject to any international regulatory controls, the first step can be skipped altogether. And also because the bromopropiophenones can be divided into batches and each batch used to produce a different cathinone, if desired (Collins et al., 2016). Theoretically, 0.42 kilograms of 4-MMC can be produced from 1 kilogram of 2-bromo-4-methylpropiophenone, a yield of approximately 45 % (Europol, 2019).

Both information from dismantled laboratories and precursor seizure data confirm that European producers mostly start the production of cathinones from the second (amination) step.

From 2017 to 2021, approximately 3.8 tonnes of precursors associated with the production of cathinones was seized in the European Union and reported to the EU drug precursors database. These seizures included 3.5 tonnes of bromopropiophenone intermediates, but only 261 kilograms of propiophenones needed for step one.

More than half of the precursors seized during this time were for the production of 4-MMC (2.0 tonnes) and 4-CMC (1.2 tonnes) (see Figure Seizures of cathinone precursors in Europe, 2017-2021, by cathinone produced), confirming the interest of European drug producers in manufacturing controlled cathinones. Almost half of all seizures were reported by the Netherlands (1.9 tonnes), followed by Germany (0.8), Luxembourg (0.5) and Poland (0.4). Seizures were also reported by Belgium, France, Hungary and Austria. As these compounds are not under legal control, seizures tend to occur only when customs irregularities are detected (such as misdeclaration) or when law enforcement investigations occur. Additional seizures (0.5 tonnes) were reported by Czechia to the Precursors Incident Communication System (PICS) hosted by the International Narcotics Control Board (INCB).

Where the origin was known, cathinone precursor shipments originated in China and India. The final destination countries included Poland, the Netherlands, Spain and the United Kingdom. Seizures of cathinone precursors not occurring at the EU external borders often occurred in illicit cathinone laboratories, mainly in Poland and the Netherlands.

Globally, EU seizures of cathinone precursors make up a modest part of all seizures reported to the INCB PICS system (approximately 5 % of seizures reported in the period 2017 to 2021), which appears to suggest that – despite the dramatic increase in production in the European Union – production remains small-scale compared with other world regions, with outputs probably destined mainly for local markets. Large seizures of cathinone precursors have taken place in China, Russia, Ukraine and Taiwan. Some seizures were associated with large cathinone laboratories in Russia and Ukraine. In China, the precursors were seized at a chemical production plant.

Notwithstanding its global ranking, both precursor seizure data and data collected from dismantled production facilities show that cathinone production is a well-established feature of the European market, especially in Poland and to a lesser extent in the Netherlands, with precursors and material for the synthesis acquired and transported via neighbouring countries (including Germany, France and Luxembourg).

The dumping of hazardous chemical waste from these production sites may result in significant environmental damage, directly affecting the surrounding areas, and possibly affecting the population and the aquatic environment (including surface and drinking water) (ter Laak and Emke, 2023).

In addition to full synthesis in Europe, chemically masked derivatives of controlled synthetic cathinones can be produced to evade detection by law enforcement such as customs agencies. In this scheme, the cathinone is chemically masked to produce a non-controlled substance, which can be converted back into the parent cathinone drug. For example, in 2019, Dutch Police seized 350 kilograms of chemically masked 3-MMC at a site linked to a producer/distributor that had apparently imported the substance from India. The 3-MMC was masked as N-acetyl-3-MMC. It is thought that this derivative was intended to be converted to 3-MMC, for example by acid hydrolysis using hydrochloric acid. Approximately 150 kilograms of 3-MMC were also seized at the site. These masked drugs are not controlled and can be ordered and transported using the same channels as new psychoactive substances.

Situation

Synthetic cathinones are the second-largest category of new psychoactive substances monitored by the EMCDDA, after synthetic cannabinoids, with the 167 cathinones representing 17 % of all new psychoactive substances. The number of cathinones reported for the first time each year in Europe has fallen from a peak of 31 substances in 2014 to 10 in 2019 and then 3 in 2023, a decrease of 90 % (see Figure Number of synthetic cathinones notified to the EU Early Warning System for the first time, European Union, 2005-2023).

After falling from a peak of 1.9 tonnes in 2016, the quantity of synthetic cathinones seized in Europe rose sharply between 2020 and 2022, increasing to 3.3 tonnes in 2020, 4.5 tonnes in 2021 and 26.5 tonnes in 2022 (see Figure Seizures of synthetic cathinones reported to the EU Early Warning System: trends in total number of seizures and quantity of material seized for all forms reported in weight, European Union, 2005-2022).

This increase was driven by a small number of large seizures by customs agencies in the Netherlands and Spain. In 2022, for example, 78 seizures of three cathinones (3-CMC, 3-MMC and alpha-PHiP) accounted for 22.3 tonnes, 84 % of the total quantity of cathinones seized during the year. Overall, these 78 seizures accounted for 73 % of the total quantity of new psychoactive substances (see Figure Top five synthetic cathinones seized by number of seizures and quantity of material seized for all forms reported in weight reported to the EU Early Warning System, European Union, 2022). All of these consignments originated from India (see Table Reported large seizures of cathinones originating from India in 2022).

Overall, approximately 25 tonnes (94 %) of the cathinones seized in 2022 was imported from India. Of this material, 21.9 tonnes (83 %) was intercepted by the Netherlands and 3.1 tonnes (12 %) was intercepted by Spain (see Box A large-seizure of synthetic cathinones originating from India – Spain, January 2022).

The number of synthetic cathinone seizures and the quantity seized varies across Europe, with the highest number of seizures carried out by police in Poland and the greatest quantities seized by customs in the Netherlands (see Figure Seizures of synthetic cathinones reported to the EU Early Warning System by country: numbers of seizures and quantity of material seized for all forms reported in weight, European Union, 2022).

Information on the price and purity of cathinones is not collected systematically in Europe. An indication of the price of four of the main cathinones (4-MMC, 3-MMC, 4-CMC and 3-CMC) on the market in the Netherlands is provided in the table Price of cathinones in the Netherlands, 2022.

Source: Central Criminal Investigations Division, Dutch Police, Netherlands.
(¹) Price based on one information source. The wholesale and street prices for tablets containing these cathinones are not available. Information on the street price of 4-CMC powder and 3-CMC powder is not available.

Cathinones were also detected in tablets (249 seizures totalling to 50 192 units and 616 seizures totalling to 7.8 kg) and, for the most part, reflect the main substances seized as powders (3-MMC, 4-MMC, 4-CMC and 3-CMC). In 2022 and 2023, signs of a possible increase in synthetic cathinones mis-sold as or used to adulterate MDMA were identified by the EU Early Warning System. While the overall scale of this issue is unknown, it has been reported by drug checking services in at least three EU Member States, namely Spain, the Netherlands and Austria. The affected products included MDMA tablets, crystals and powders, typically containing 4-CMC, 3-MMC, 3-CMC, 4-MMC and dipentylone.

Source data

All of the source data used in graphics and data tables may be found in our Data catalogue.

References

Consult the list of references used in this module.