Canada’s Standardised THC Unit?
Since recreational cannabis first began being sold legally in Canada in 2018, the range of products on offer has expanded massively. Not only is there more choice than ever in terms of types of products and ways of using them, but also in terms of the levels of the active component, delta-9-tetrahydrocannabinol (THC). The trend both in Canada and internationally is for stronger, more potent cannabis products, which means higher levels of THC.(Hammond et al., 2022) But research has shown that most consumers are not familiar with THC levels, nor with what constitutes a ‘low’ or ‘high’ dose of THC.(Leos-Toro et al., 2020; Lineham et al., 2023) This can lead to people accidentally over-consuming, resulting in unwanted side-effects and negative health consequences.
A recent paper by Shea Wood and colleagues published in the International Journal of Drug Policy presents the idea of adopting a standardised THC unit in Canada.(Wood et al., 2024) The standard Canadian THC unit recommended by the authors is 2.5 mg, which research suggests would be enough to produce a ‘high’.(Kleinloog et al., 2014) This dose also follows suggestions of selecting a standard unit that is low enough to be unlikely to cause serious side effects in new cannabis users, who are likely to have low tolerance to THC and a greater need for guidance.(Chester et al., 2020) The aim of using a standard THC unit would be to better inform consumers and empower them to make evidence-based decisions in their product choice and consumption of cannabis. A similar standard THC unit is already used by cannabis researchers, but there is still a lot to consider before adopting it across the Canadian cannabis market.
Currently, cannabis sold in Canada is labelled with the amounts of THC as either a concentration or amount per dose, as well as the total amount per container.(Government of Canada, 2024) However, there is a lot of inconsistency in labelling between different types of products and between different provinces, which can make it harder for consumers to relate the THC numbers to how strong the product is. The use of a standard unit, Wood and their colleagues argue, would help people to understand the strength of a cannabis product, making it easier for consumers to predict how it will affect them. By adding how much of a product contains a standard unit, for example 1ml of vape fluid or 2 pieces of an edible, consumers could decide on how they use a product beforehand, rather than trying to titrate their use during consumption. It could also make it simpler to monitor market trends and estimate how much THC the population is using over time, and how the potency of cannabis products themselves are changing.
One key issue is how to apply a single THC unit to all types of cannabis products, regardless of how they’re used. For example, THC is usually less well absorbed by the body when it’s eaten compared to when it’s smoked or vaped, meaning less reaches the brain. Wood and colleagues reason that even less of the THC in edible products is absorbed, the effects balance out because more THC is converted to 11-hydroxy-THC, which is equally or more psychoactive than THC. However, the authors note that more research is needed to better understand how the THC in different types of cannabis affects people, especially since there are many other cannabinoids, such as cannabidiol (CBD) and delta-8-THC, that also differ between products.
Choosing and implementing a Canadian THC unit will require us to consider many factors, including how much THC can cause health problems if used frequently over a long period of time, and how the standardised unit would fit into current public health guidelines and policy. There are also other experts who maintain that the current method of measuring THC in milligrams can meet all of the same needs as the proposed standard unit. Should a standard THC unit be adopted in Canada, a long-term public education campaign will be required to teach consumers what a THC unit represents and how it may differ between products. Ultimately, any decision taken must meet the central purpose of the Cannabis Act, “to protect public health and public safety”.(Government of Canada, 2018)
Article by Lucy Chester
References
Chester, L. A., Chesney, E., Oliver, D., Wilson, J., & Englund, A. (2020). How experimental cannabinoid studies will inform the standardized THC unit. Addiction, 115(7), 1217-1218. https://doi.org/10.1111/add.14959
Government of Canada. (2018). Cannabis Act (S. C. 2018, c. 16). Retrieved 20/11/2024 16:50 from https://laws-lois.justice.gc.ca/eng/acts/c-24.5/
Government of Canada. (2024, 30/01/2024). How to read and understand a cannabis product label. Retrieved 20/11/2024 16:05 from https://www.canada.ca/en/health-canada/services/drugs-medication/cannabis/personal-use/how-read-understand-cannabis-product-label.html
Hammond, D., Goodman, S., Wadsworth, E., Freeman, T. P., Kilmer, B., Schauer, G., Pacula, R. L., & Hall, W. (2022). Trends in the use of cannabis products in Canada and the USA, 2018 – 2020: Findings from the International Cannabis Policy Study. Int J Drug Policy, 105, 103716. https://doi.org/10.1016/j.drugpo.2022.103716
Kleinloog, D., Roozen, F., De Winter, W., Freijer, J., & Van Gerven, J. (2014). Profiling the subjective effects of Δ 9 -tetrahydrocannabinol using visual analogue scales. In International Journal of Methods in Psychiatric Research (Vol. 23, pp. 245-256).
Leos-Toro, C., Fong, G. T., Meyer, S. B., & Hammond, D. (2020). Cannabis labelling and consumer understanding of THC levels and serving sizes. Drug Alcohol Depend, 208, 107843. https://doi.org/10.1016/j.drugalcdep.2020.107843
Lineham, J., Wadsworth, E., & Hammond, D. (2023). Self-reported THC content and associations with perceptions of feeling high among cannabis consumers. Drug Alcohol Rev, 42(5), 1142-1152. https://doi.org/10.1111/dar.13664
Wood, S., Gabrys, R., Freeman, T., & Hammond, D. (2024). Canada’s THC unit: Applications for the legal cannabis market. International Journal of Drug Policy, 128, 104457. https://doi.org/https://doi.org/10.1016/j.drugpo.2024.104457