Wada keeps weight-loss drugs off its 2027 banned list
Ozempic and Mounjaro stay on the monitoring list while studies test whether they do anything at all for lean, highly trained athletes.
Athletes will not be banned from taking weight-loss drugs such as Ozempic and Mounjaro under the World Anti-Doping Agency's rules for 2027, but the drugs stay on the agency's monitoring list while it works out whether they do anything for performance.
Wada confirmed the decision after a meeting of its executive committee, which continues to examine both the potential of the drugs — known as GLP-1 receptor agonists — to enhance performance, and the risk of their abuse in sport. The rules take effect in January and are reviewed every year.
The test a drug has to fail
The decision is easier to understand once the threshold is clear. To move from the monitoring list to the prohibited list, a substance must meet two of three criteria: that it can enhance sport performance, that it poses a health risk to the athlete, or that it violates the spirit of sport.
Semaglutide, marketed as Ozempic and Wegovy, went onto the monitoring list in 2024. Tirzepatide, branded as Mounjaro, was added this year. Neither has yet been shown to clear the bar.
The gap is in the first criterion, and it is a genuine gap rather than a bureaucratic one. Almost everything known about these drugs comes from studies of people who are obese. Whether the same physiological effects appear in lean, highly trained athletes is not established.
The question, said Professor Olivier Rabin, Wada's senior director for science and medicine, is "whether some of the pharmacological impact on human physiology that has been observed in obese patients" would also appear "in non-obese, highly trained people".
Wada has started one study and is preparing another, testing the drugs in conditions designed to mimic high-level exercise.
"It's still going to take us a little bit of time to collect all this information," Rabin said, because the work involves "highly controlled studies in very specific conditions".
Why the benefit may not be a benefit
The reason Wada is not simply assuming an advantage is that the mechanism cuts both ways for an athlete.
Rabin said potential benefits could be offset by side effects including nausea, fatigue and loss of muscle mass — and it is the last of those that matters most in a sporting context.
"If you're an athlete and you lose muscle mass, that may be very counterproductive," he said.
Rabin's point is that the two effects can cancel: an athlete who arrives lighter but has lost muscle with the weight has not gained anything.
That is the substantive question the studies have to answer, and it explains why a ban would be premature: prohibiting a substance that does not improve performance would punish athletes without protecting anyone.
The warning that came with the decision
Not banning is not the same as approving, and Rabin was blunt about the distinction.
He warned athletes to be "very careful using those drugs and never without medical advice and supervision".
"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.
An athlete reading the 2027 list will see that these drugs are permitted. Wada's medical director is telling them that permitted and safe are different words.
Sport catching up with everyone else
The context for all of this is that these medications have become common well outside elite sport. Serena Williams, the 23-time Grand Slam singles champion, revealed last year — while on a break from professional tennis — that she had been using weight-loss medication.
That is the practical problem for an anti-doping system: a medication in wide general use, reaching athletes through ordinary prescriptions, is a harder thing to police than a drug made for performance.
Keeping it on the monitoring list is the middle path: Wada collects data on how often athletes are using these drugs, without sanctioning anyone, while it establishes whether there is anything to sanction.
What happens next
The 2027 list takes effect in January and will be reviewed again a year later. Two studies are running or being prepared, and their findings on non-obese, highly trained subjects are what would move these drugs from one list to the other.
Until then the position is settled but provisional: permitted, watched, and accompanied by an explicit warning from the agency that permits them.
