Professional athletes are turning to cannabis products to help them manage pain, but leagues such as the NFL aren’t yet ready to get on board.

Last week, the league said it wants to see more studies of how cannabis affects fitness. At the moment, there’s no scientific evidence that the products work, or that they’re safe, NFL officials said. Additionally, elite professionals aren’t your average jock — a lot of money is at stake and the NFL wants to know exactly how cannabis will affect their performance.

Kevin Hill, a doctor who co-chairs a committee on pain management for the NFL and its players’ association, sounded a note of caution: “There is a growing body of evidence that suggests it’s a little bit more risky than people think,” Hill said.

He cited concerns about the purity and potency of cannabis products, as well as potential interactions with other drugs that players take. There’s also concern that the high doses of cannabis products needed to treat pain can cause liver damage.

While the World Anti-Doping Agency now allows CBD (but not THC, the psychoactive ingredient in marijuana), the NCAA still bans all “cannabinoids” broadly. It says marijuana may impair performance, citing the potential for memory impairment, decreased judgment and reduced coordination.

This isn’t stopping the products from gaining appeal, and companies are already marketing them as a new form of sports medicine. Canopy Growth Corp., for example, has a majority stake in BioSteel, which makes CBD products aimed at sports recovery, including some that contain electrolytes for hydration.

“We know CBD and cannabinoids can help with overall well-being, and it is very encouraging to see the dialogue about athletic use of these products come to light,” Michael Cammalleri, cofounder of BioSteel, told me in an email.

A number of athletes, such as former NFL player Brett Favre, have endorsed cannabis products.

“We are seeing increased awareness and acceptance of CBD products to help with recovery and performance across sports categories,” Erick Dickens, chief executive officer of Kadenwood, said in an email.

The company, which makes the Level Select line of CBD products marketed to athletes, said year-to-date online sales have grown 74%. It recently started a new ad campaign featuring PGA golfer Rickie Fowler, Heisman Trophy winner and former NFL quarterback Carson Palmer and former MLB star Steve Garvey.

The percentage of people who use cannabis-related products for athletics is still fairly small, at about 8% of current annual consumers, according to cannabis statistic tracker New Frontier Data. But it will certainly grow if the NFL concludes that it’s good enough for elite athletes.