Legal Cannabis Product Labeling Misses the Mark in Canada
The first study of the label accuracy of cannabis oil products in the legal Canadian market found “discrepancies at multiple levels,” the authors wrote. One third of products purchased for the study differed from their online tetrahydrocannabinol (THC) and cannabidiol (CBD) descriptions, and 16.7% had conflicting information on the label.
“Research from US legal markets has found issues with label inaccuracy of THC and CBD content on legal cannabis products, but despite nearly five years of legalization, no study had similarly looked at products in the Canadian market,” study authors James MacKillop, PhD, professor of psychiatry and behavioral neurosciences, and Amanda Doggett, PhD, postdoctoral fellow, both at McMaster University in Hamilton, Ontario, Canada, told Medscape Medical News.
The study was published on June 5, 2024, in JAMA Network Open.
“A key benefit of legalization is the regulatory framework that governs product composition, but if the label accuracy requirements aren’t being adhered to, then this goal of the Cannabis Act is not being realized,” they said. “In fact, one reason we selected cannabis oils was because the uniform formulation (unlike plant matter or foods) was expected to set a high benchmark for accuracy.”
The inaccuracies mean that many consumers don’t know the THC levels of the products they’re taking and “lack basic context for understanding THC amounts when provided with the numbers,” said David Hammond, PhD, professor of public health sciences at the University of Waterloo and author of a commentary on communicating THC levels and dose to consumers.
“Most general clinicians feel inadequately prepared to discuss the specifics of cannabis consumption,” 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.”
Faulty Labeling
Canadian federal cannabis regulations specify that the allowable variability between labeled and actual amounts of THC and CBD in a commercial product is ±15%. But many of the products that Doggett and MacKillop examined failed to meet this requirement.
The authors tracked all oral oil products that were available on the Ontario Cannabis Store (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.
For comparability to other research, they divided the number of products that exceeded the variability limit by the number of products tested. Given that very-low–concentration products could exceed this threshold with tiny absolute increases, they also conducted a subgroup analysis of higher-potency products (≥ 2.5 mg/g THC), as defined by OCS consumer guidance.
Discrepancies between information on the OCS website regarding advertised amounts of THC and CBD and physical product labels were identified for 10 of the oil products (33.3%).
The researchers also found internal inconsistency. Five products (16.7%) were labeled with discordant THC/CBD (denoting active cannabinoid content) and total THC/CBD (denoting cannabinoid content after product is heated for consumption) concentrations. This was “surprising” and “perplexing,” said Doggett and MacKillop, given that those amounts are supposed to be identical for cannabis oil products. The product with the largest discrepancy was labeled as having 5 mg/g CBD but 26 mg/g total CBD.
Assay levels indicated that 12 products (40%) were outside the variability limit for THC, and three (10%) were outside the variability limit for CBD, with greater labeled vs laboratory-tested amounts for all but one product.
Among 16 products that had a label amount of ≥ 2.5 mg/g THC, seven (43.8%) had amounts that were > 15% lower than what was labeled.
“No products contained more THC than labeled at an amount that would be expected to have substantively different psychoactive effects,” the researchers wrote. “However, given that many medical consumers obtain products from the nonmedical market, one implication is inaccurate dosing.”
“We can’t say for sure, but it does seem likely these discrepancies are larger than one would expect 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. Yet other recent studies have shown similar results.
One study by German researchers analyzed the labeling accuracy in a range of cannabis-containing foods, food supplements, and other products. Only 27 of the 35 products explicitly listed CBD content. In 33% of the samples, the analyzed value matched the content given on the label, whereas 26% exceeded the declared CBD content, and 41% contained lower amounts. CBD products with an unclear or not defined CBD content were mostly below the limit of detection.
The authors concluded that this “is still a constantly evolving product sector, [and] depending on the type and origin of the products, there may be significant discrepancies between the marketing and the actual ingredients contained, making the market less transparent for consumers.”
Another recent study of the label accuracy of hemp-derived topical products looked at 105 products, 45 of which were purchased from retail locations in the United States and 60 were purchased online. Of the 89 products that listed a total amount of CBD on the label, 18% were overlabeled (ie, they had > 10% less CBD than advertised), 58% were underlabeled (> 10% more CBD than advertised), and 24% were accurately labeled for CBD. THC was detected in 35% of products (all contained less than the 0.3% legal limit for hemp). Furthermore, the products often made cosmetic or therapeutic claims.
“These findings suggest that improved regulatory oversight of cannabis and hemp products is needed to ensure quality assurance, deter misleading health claims, and potentially prevent unwanted drug effects among consumers,” the authors concluded.
Indeed, although Canada’s Cannabis Act is said to create “a strict legal framework for controlling the production, distribution, sale, and possession of cannabis across Canada,” enforcement seems to be lax.
“Penalties, including fines up to $1,000,000, do exist within the cannabis regulations, but there is no publicly available list of list of violations and penalties, and there are reports of limited enforcement,” said Doggett and MacKillop. “A recall system exists but is not commonly used; there have been fewer than 100 recalls since legalization took effect. Our findings suggest that large proportions of products (at least oils) would be inaccurately labelled according to the regulations and probably would have met criteria for a recall.”
Public Education Needed
“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 the amount being ingested,” said Hammond.
In his commentary, he suggested the following five principles for ensuring that cannabis product labels are clear and easy to understand and minimize the risks for overconsumption:
- THC content should be clearly labeled and require minimal numeracy to understand.
- The standard dose or serving of THC labeled on products should be lower than the typical level required to induce intoxication for most consumers.
- Labeling should provide guidance on THC amounts or “dose expression.”
- To the extent possible, labeling should provide a common basis for comparisons between products.
- THC labeling should be reinforced by other packaging regulations, such as unit-dose packaging.
Even as labels evolve, however, they “should not take the place of public education on cannabis potency and different modes of administration,” Hammond concluded.
Several resources are available to help clinicians talk to patients about medical or recreational cannabis use. These include information from the Centre for Effective Practice, which offers a tool to equip primary care providers with evidence-based information on nonmedical cannabis use; the Canadian government’s “Talk about cannabis” resources; the College of Family Physicians of Canada‘s guidance on authorizing cannabis product use in primary care; and Manitoba Health‘s “Cannabis Information for Health Care Professionals.”
Doggett and Hammond’s case series was funded by the DeGroote Centre for Medicinal Cannabis Research at McMaster University and St Joseph’s Healthcare Hamilton. MacKillop is supported by the Peter Boris Chair in Addictions Research and 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.
