This study provides evidence of a rapidly evolving and active online marketplace from which SCRA vaping products seem to be easily obtainable, but also difficult to identify as controlled substances. Using simple search terms on a widely used search engine, we identified 62 websites selling SCRA vaping products, with 1225 individual listings and 128 unique brands. Although not a direct comparison, a survey of SCRA availability on the “dark web” in 2016 and 2017 which used different methodology to this study [15] found 32 individual SCRA branded vape products, which may suggest that this market has grown in the interim and/or that suppliers are increasingly marketing these on the surface web rather than the dark web.

There was evidence of both UK-based and international production and trade of these products. There was also evidence of companies competing for custom by offering incentives and discounts, including a wide variety of payment methods, measures to evade detection by law enforcement, and methods of ensuring anonymity in both payment and delivery.

As found in previous SCRA studies [31], products were heavily marketised, with colourful branding and abstract names that gave little or no hint of the contents of the product. Several SCRA vaping product brand names found in this survey have been listed in a previous survey of SCRA vaping products, such as “Bizarro”, “Diablo” and “Green Giant” [15], and in a survey of non-vape SCRA products, such as “K2” and “Mr Nice Guy” [31]. However, many previously common SCRA brand names were not found and many new brand names had appeared. This suggests a rapidly changing marketplace with ongoing product development and marketing.

SCRA vaping products were almost exclusively on sale as liquid formulations for refilling EVDs. It therefore does not appear that the rise in popularity of disposable nicotine e-cigarettes [17] has so far impacted on the online SCRA vaping product market. The most common bottle size on sale was 5mL. Given the lack of data on the concentration of SCRA in these liquids, it is difficult to quantify how many SCRA doses this may constitute. However, this volume of liquid is likely to provide at least several hundred puffs and, given the potency of known SCRAs, this is likely to represent several hundred psychoactive “doses”. For reference, since 2020 UK e-cigarette tanks are limited to a maximum volume of 2mL.

SCRA vaping products were offered both in small volumes consistent with supply for personal use, and large volumes suggestive of supply for further distribution. Prices varied significantly by brand, website and by the size of the purchase, however average prices by volume were similar to those found in a previous survey [15].

Of the minority (4.5%) of SCRA vaping products in which an active compound was listed, the most common was 5 F-AKB48. This fourth generation SCRA [32] was also a common compound found in a previous Europe-wide SCRA snapshot survey performed in 2017 [16] and in serum analyses of patients presenting with drug toxicity to an emergency department in London in 2015 [33]. Of the other SCRA compounds listed in this study, they were a combination of first generation (e.g. JWH-018) and later generation SCRA compounds. It is likely that 5 F-MDMB-PINACA and 5 F-ADB refer to the same compound as each other, as do 5 F-CUMYL-PINACA and SGT-25 [34]. Interestingly, there was no advertising of AB-CHMINACA or MDMB-CHMICA, two SCRA compounds which have become relatively well-known for being associated with significant toxicity [35–37].

Several factors raise concerns that SCRA vaping products could be purchased and consumed by undiscerning customers, or misused even by experienced consumers. Websites were easily accessed and products were available at a range of prices. Products were generally sold with minimal or no explanation of their contents or how to use them. Where descriptions of ingredients or psychoactive effects were provided, they tended to be abstract, vague or incorrect. There was generally no information on the chemical make-up of active ingredients or solvents, conditions of preservation, expiry date or EVD settings necessary for use. SCRA vaping products were often sold alongside legal products such as nicotine-containing EVDs or CBD products and, concerningly, many websites stated their products were legal.

We used standardised methodology developed by the EMCDDA which has been used in multiple studies in recent years [28, 29]. Nevertheless, the websites found were limited by the search methods and search terms chosen. Information on websites could not be confirmed, particularly as no purchases were made and no chemical analyses were performed; in fact, it is likely some information on websites was faked in order to evade identification and legal action. There is no way of knowing actual numbers of sales from these websites, especially given the anonymity afforded by their payment options– indeed, the authors of a previous snapshot study struggled to obtain some ordered samples [16]. Here, products clearly intended for vaping were studied, however it is noted that EVDs with correct settings can be used to inhale most drug forms including powders and herbs sprayed with active ingredient.

Further studies are needed, both to purchase and confirm the chemistry of these products, and to assess the pattern of their use and their clinical effects on end users. Nonetheless, the ease with which these products can be obtained has implications both for clinicians and policymakers,

Clinicians assessing patients experiencing the toxic effects of products purchased online should be aware of the availability of SCRAs and their potential use in EVDs. Thorough toxicological assessment should always include questions on inhalation of substances via vape, and the name of any vaped substances should be enquired about–product names identified in this study can be used for reference if SCRA use is suspected. Clinicians should be aware that patients may believe that the substances they have inhaled are legal.

Policymakers, both in the UK and elsewhere, should be aware that legislation making SCRA products illegal has not limited the expansion of an easily accessible online SCRA marketplace. The apparent international nature of trade in SCRA products suggests that international cooperation may be needed when exploring approaches to limiting their distribution, while the presence of SCRA products on the surface web suggests dialogue between policymakers and tech companies may also be important when exploring ways to reduce harm from these products. The ease of availability of NPS specifically for use with EVDs on the surface web is of relevance to policy decisions regarding vaping in general. Ongoing monitoring of the online market place, in conjunction with data from drug seizures, hospital presentations and other monitoring tools, is needed to maintain an understanding of evolving patterns of trade and use of SCRA vaping products, in order to inform future policy aimed at limiting the potential harms caused by the sale and use of these substances.