The legalization of cannabis oil and other non-medical cannabis products in Canada in 2018 has not led to better quality control and accurate labeling of the products, according to new research.
The first study of the label accuracy of cannabis oil products in the Canadian legal market found “discrepancies at several levels,” the authors wrote. One third of the products purchased for the study differed from their online descriptions of tetrahydrocannabinol (THC) and cannabidiol (CBD), and 16.7% had conflicting information on the label.
“Research into US legal markets has found problems with label inaccuracy of THC and CBD content in legal cannabis products, but despite nearly five years of legalization, no study had similarly analyzed products on the market Canadian,” study authors James MacKillop, PhD. professor of psychiatry and behavioral neuroscience, and Amanda Doggett, PhD, a postdoctoral fellow, both at McMaster University in Hamilton, Ontario, Canada, told Medscape Medical News.
The study was published June 5, 2024, in JAMA Network Open.
“A key benefit of legalization is the regulatory framework that governs product composition, but if label accuracy requirements are not met, this objective of the Cannabis Act is not being realised,” they said. “In fact, one of the reasons we selected cannabis oils was because the uniform formulation (as opposed to plant matter or food) was expected to set a high benchmark for accuracy.”
The inaccuracies mean many consumers don’t know the THC levels of the products they take and “lack the basic context to understand THC amounts when the numbers are provided,” said David Hammond, PhD, professor of public health sciences at the University. of Waterloo and author of a commentary on communicating THC levels and doses to consumers.
“Most general practitioners feel unprepared to discuss the details of cannabis use,” he told Medscape Medical News. “One of the challenges is that our understanding of the potential therapeutic benefits of cannabinoids like CBD is at an early stage, with more speculation than evidence.”
Defective labeling
Canadian federal cannabis regulations specify that the allowable variability between the labeled and actual amounts of THC and CBD in a commercial product is ±15%. But many of the products Doggett and MacKillop examined did not meet this requirement.
The authors tracked all oral oil products that were available on the Ontario Cannabis Shop (OCS) website between November 2021 and January 2022 and randomly selected 30 that were available at least twice during the study period. High performance liquid chromatography was used to quantify the amounts of CBD and THC in each product.
To compare with other research, they divided the number of products that exceeded the limit of variability by the number of products tested. Since very low concentration products could exceed this threshold with tiny absolute increases, they also performed a subgroup analysis of higher potency products (≥ 2.5 mg/g THC), as defined in the consumer guide OCS.
Discrepancies were identified between the information on the OCS website about the declared amounts of THC and CBD and the physical product labels for 10 of the oil products (33.3%).
The researchers also found internal inconsistency. Five products (16.7%) were labeled with discordant concentrations of THC/CBD (denoting active cannabinoid content) and total THC/CBD (denoting cannabinoid content after heating the product for consumption) . This was “surprising” and “puzzling”, Doggett and MacKillop said, given that these amounts are supposed to be identical for cannabis oil products. The product with the largest discrepancy was labeled with 5 mg/g CBD but 26 mg/g total CBD.
Assay levels indicated that 12 products (40%) were outside the limit of variability for THC, and three (10%) were outside the limit of variability for CBD, with amounts markedly higher than those tested in the laboratory for all the products minus one.
Among 16 products that had a labeled amount of ≥ 2.5 mg/g THC, seven (43.8%) had amounts >15% lower than those labeled.
“Neither product contained more THC than is labeled in an amount that would be expected to have substantially different psychoactive effects,” the researchers wrote. “However, since many medical consumers obtain products from the non-medical market, one implication is inaccurate dosing.”
“We can’t say for sure, but it seems likely that these discrepancies are larger than would be expected for other health products and especially for prescription drugs,” Doggett and MacKillop told Medscape Medical News.
Other cannabis products
The case series was limited by its focus on cannabis oils, with “uncertain generalizability to other product types,” the researchers wrote. However, other recent studies have shown similar results.
A study by German researchers looked at the accuracy of labeling on a range of cannabis-containing foods, dietary supplements and other products. Only 27 of the 35 products explicitly include CBD content. In 33% of the samples, the analyzed value matched the content indicated on the label, while 26% exceeded the declared CBD content and 41% contained lower amounts. CBD products with unclear or undefined CBD content were mostly below the detection limit.
The authors concluded that this “is still an evolving product sector, [and] depending on the type and origin of the products, there can be significant discrepancies between the marketing and the actual ingredients contained, making the market less transparent for consumers.”
Another recent study on the label accuracy of hemp-derived topical products looked at 105 products, 45 of which were purchased at retail locations in the United States and 60 of which were purchased online. Of the 89 products with a total amount of CBD on the label, 18% were overlabeled (ie had > 10% less CBD than advertised), 58% were underlabeled (> 10% more of CBD than advertised) and 24% were accurately labeled for CBD. THC was detected in 35% of the products (all contained less than the 0.3% legal limit for hemp). In addition, products often made cosmetic or therapeutic claims.
“These findings suggest that enhanced regulatory oversight of cannabis and hemp products is needed to ensure quality assurance, deter misleading health claims, and potentially prevent unintended drug effects among consumers,” the researchers concluded. authors
Indeed, while the Canadian Cannabis Act is said to create “a strict legal framework to control the production, distribution, sale and possession of cannabis across Canada,” enforcement appears to be lax.
“Penalties, including fines of up to $1,000,000, exist within the cannabis regulations, but there is no publicly available list of violations and penalties, and there are reports of limited enforcement,” Doggett and MacKillop said. “A recall system exists, but it is not routinely used; there have been fewer than 100 recalls since the legalization came into force. Our findings suggest that large proportions of products (at least oils) would be mislabelled according to the regulations and would probably have met the criteria for a recall.”
Need for public education
“Understanding the strength of products and how this translates into how much people should consume is particularly important for products such as oils, liquids and edibles, which have very few visual or sensory cues about how much is being ingested” , Hammond said.
In his commentary, he suggested the following five principles to ensure that cannabis product labels are clear and easy to understand and minimize the risks of overuse:
- THC content must be clearly labeled and requires a minimum of arithmetic to understand.
- The standard dose or portion of THC labeled on products should be below the typical level required to induce intoxication for most consumers.
- Labeling should provide guidance on amounts of THC or “dose expression.”
- As far as possible, labeling should provide a common basis for comparisons between products.
- THC labeling should be reinforced with other packaging regulations, such as unit dose packaging.
Even as labels evolve, however, “they should not replace public education about the potency of cannabis and the different modes of administration,” Hammond concluded.
There are several resources available to help doctors talk to patients about medical or recreational cannabis use. These include information from the Center for Effective Practice, which provides a tool to equip primary care providers with evidence-based information about non-medical cannabis use; Canadian government resources “Talk about cannabis”; the College of Family Physicians of Canada guidance on the authorization of the use of cannabis products in primary care; and “Cannabis Information for Health Professionals” from Manitoba Health.
Doggett and Hammond’s case series was funded by the DeGroote Center for Medicinal Cannabis Research at McMaster University and St Joseph’s Healthcare Hamilton. MacKillop is supported by the Peter Boris Chair in Addiction Research and the Canada Research Chair in Translational Addiction Research. MacKillop reported receiving unrestricted research grants from the National Institutes of Health, Canadian Institutes of Health Research (CIHR), and Health Canada. Hammond’s commentary was supported by a CIHR Project Bridge grant. Additional support was provided by a CIHR Research Chair in Applied Public Health. Hammond declared no relevant financial relationships.
Marilynn Larkin, MA, is an award-winning medical writer and editor whose work has appeared in numerous publications, including Medscape Medical News and its sister publication MDedge, The Lancet (where she was a contributing editor), and Reuters Health.