Weight-loss drugs in sport: Ozempic, Mounjaro not on Wada banned list for athletes

Weight-loss drugs such as Ozempic and Mounjaro have become increasingly common outside elite sport

Athletes will not be banned from taking weight-loss drugs under the World Anti-Doping Agency's rules for 2027, but the substances will remain on its monitoring list.

The 23-time Grand Slam singles champion Serena Williams revealed last year - while on a break from professional tennis - that she had been using weight-loss medication.

"It's such a drastic change in your physiology that it can come with serious side effects and risks, in particular for athletes," he told BBC Sport.

Semaglutide, often marketed under the Ozempic and Wegovy banners, was first placed on Wada's monitoring list in 2024. Tirzepatide, commonly branded as Mounjaro, was added this year.

Wada has started one study and is preparing another to examine the effects of the drugs in conditions designed to mimic high-level exercise.

"What we want to see is whether some of the pharmacological impact on human physiology that has been observed in obese patients would also occur in non-obese, highly trained people."

"If you're an athlete and you lose muscle mass, that may be very counterproductive for what you're trying to achieve," he said.

Under the usual timetable, a change approved at next September's executive committee meeting would take effect in January 2028.

Weight-loss drugs seem most likely to appeal to athletes in weight-category sports such as boxing and wrestling, as well as horse racing, where jockeys have to meet strict weight requirements.

"There are sports as well where aesthetics play a role," he said. "It can be gymnastics, can be horse riding, can be many different sports where you don't have weight categories, but physical appearance is quite important."

She is also a spokesperson for Ro, a company which sells GLP-1s and in which her husband is an investor.