Legalizing the adult use marijuana market in Canada led to “immediate” and “sustained” declines in illicit market cannabis sales, according to data published online in the International Journal of Drug Policy.

Researchers affiliated with McMaster University in Ontario assessed Canadian marijuana market trends during the five years immediately following legalization.

They reported: “RCL [recreational cannabis legalization] implementation was followed by an immediate reduction and sustained declining trend in the illegal cannabis market, suggesting RCL is achieving one of the government’s goals by ‘keeping profits out of the hands of criminals.’ … This decline additionally means fewer people are consuming products [from the unregulated market] with unknown safety profiles and potential contaminants.”

The study’s authors concluded, “Recreational cannabis legalization in Canada appears to be achieving one of its primary goals by displacing the illegal cannabis market.”

The findings are consistent with prior data finding that only four percent of Canadian cannabis consumers acknowledge purchasing cannabis products from unregulated sources.

Data from the United States similarly reports that a growing percentage of American consumers are transitioning to the legal marketplace. According to a 2023 survey, 52 percent of consumers residing in legal states said that they primarily sourced their cannabis products from brick-and-mortal establishments. By contrast, only six percent of respondents said that they primarily purchased cannabis from a “dealer.” Many consumers residing in non-legal states also report frequently traveling to neighboring legal states to purchase licensed cannabis products and returning home with them.

Canada legalized the adult-use market in 2018. Public support for the policy remains high, with about six and ten Canadians currently endorsing legalization.

The full text of the study, “Association. Of recreational cannabis legalization with changes in medical, illegal, and total cannabis expenditures in Canada,” appears in the International Journal of Drug Policy.