How important are health warnings on pot products?

Researchers from the University of Waterloo found that prominent health warnings upped the perceived risk of harm and lowered product appeal.

The GrowthOp 4 minute read September 9, 2021

FILE: A warning label on ONE gram of cannabis is seen at Up's cannabis factory in Lincoln, Ontario. Lars Hagberg / AFP / Getty Images

Researchers looking at cannabis packaging in both Canada and the U.S. found that prominent health warnings upped the perceived risk of harm and lowered product appeal.

“Products with health warnings were rated significantly less appealing and more harmful than those with no warning,” note authors of the study published online this week in Preventive Medicine.

Researchers from the University of Waterloo (U of W) wanted to find out what effect health warnings and restricted brand imagery have on how cannabis products are perceived. To do so, investigators gathered input from 45,378, randomized participants in Canada and the U.S. who viewed packages of three cannabis brands in 2019.

The study authors considered four branding conditions, ranging from no brand imagery and uniform colours to full brand imagery. They then tested differences between conditions on product appeal, perceived harm and free recall of warning messages, which addressed pregnancy, adolescent risk and impaired driving.

“Overall, full branding and plain packaging were rated the most and least appealing, respectively,” the study authors write. Additionally, products were rated as significantly less harmful when they had a white background with no or limited branding versus a coloured background, and message recall was significantly higher for Canadian versus U.S. health warnings.

In general, researchers found that reducing the amount of brand imagery modestly decreased product appeal. But so-called “plain packaging” with prominent health warnings not only increased perceived risk of harm, they reduced overall appeal.

Because message recall was greater for “those who saw plain versus fully branded packages for two of the three warning messages,” investigators suggest that jurisdictions legalizing cannabis consider both health warnings and branding restrictions in their rules.

The recommendation is in line with a U of W study published in 2019.

Investigators found that packages with full branding were regarded as more appealing and more likely to be youth-oriented, while products with health warnings were seen as less appealing than those without warnings.

“Comprehensive health warnings and ‘plain packaging’ regulations may reduce the appeal of cannabis products in a legal market. The results also provide empirical evidence that edible gummies are perceived to appeal to youth,” study authors concluded.

In another review by David Hammond, a co-author of the most recent study, Hammond identified a need for “regulated cannabis markets to develop more effective packaging and labelling standards to allow consumers to effectively titrate their THC intake, with the goal of promoting lower-risk cannabis use.”


Canada’s Cannabis Act and Cannabis Regulations detail prohibitions around marijuana product packaging and labelling. These products cannot be appealing to young people, include any testimonial or endorsement, depict a person, character or animal, or evoke an emotion regarding a way of life that includes glamour, recreation, excitement, vitality, risk or daring.

Using a brand element that could associate the cannabis product with a tobacco, vaping or alcoholic beverage product, or “create the impression that health or cosmetic benefits may be derived from” its use is also prohibited.

Canada has opted for plain packaging and labelling for all cannabis products, with restrictions on logos, colours, branding and specific display formats. “Plain packaging and labelling applies to all surfaces, including labels and the various types and parts of the package such as containers, wrappers, and coverings,” the government notes.

Additionally, weed products must come in a child-resistant container, be labelled with the standardized cannabis symbol, display the mandatory health warning message, and include specific product information.

An article earlier this year in The Conversation noted that cannabis producers should have more packaging and labelling flexibility. “It would also better support federal cannabis policy, as existing rules inadvertently encourage higher potency while sidelining other aspects of quality.”

U.S.-based Smithers, a multinational provider of testing, consulting, information, and compliance services, forecasts the global cannabis packaging market value will reach US$1.6 billion ($2 billion) in 2024.