Professional athletes across multiple sports are increasingly using weight-loss drugs without medical necessity, according to new research conducted by Loughborough University. The study, which surveyed 114 physicians working with national-level and elite athletes in 93 sports across 38 countries, found that one in ten doctors had direct knowledge of such cases. The findings highlight a growing concern about the misuse of medications such as semaglutide and tirzepatide, which are currently monitored by the World Anti-Doping Agency (WADA) and may face further restrictions.

The drugs in question, semaglutide and tirzepatide, act primarily as appetite suppressants and slow digestive processes. Semaglutide is the active ingredient in popular weight-loss medications Ozempic and Wegovy, while tirzepatide is found in Mounjaro. Semaglutide was added to WADA’s monitoring list in 2024, with tirzepatide following this year. WADA’s executive committee is scheduled to meet in September to consider whether these drugs should be added to the list of prohibited substances.

The sports most frequently associated with the use of these drugs include swimming, diving, artistic swimming, badminton, cycling, volleyball, equestrian events, horse racing, and bodybuilding. Many of these sports are weight-sensitive or require athletes to wear skin-tight clothing. Physicians cited weight classes in sports like boxing and judo, as well as the need to maintain a lower weight after injury or for aesthetic reasons in sports such as gymnastics and horse racing, as key motivations behind the drug use.

While 44% of the physicians surveyed believe these medications should be banned due to potential health risks, only minimal positive tests have been officially recorded. WADA reports just two positive tests for semaglutide and tirzepatide from more than 8,400 out-of-competition urine samples collected in 2025. However, the new research suggests actual usage has risen substantially since then.

Experts caution that the short-term benefits of rapid weight loss—such as enhanced speed, jumping ability, and endurance—may be offset by longer-term adverse effects, including muscle loss and compromised strength. Sports scientist Simon Brundish notes that some athletes in football and tennis have reportedly adopted these drugs, potentially changing their physique and performance during competitive seasons. He warns that the initial performance boost from weight reduction may be temporary and followed by a decline as power-to-weight ratios decrease.

Concerns also extend to athlete health beyond physical performance. Relative Energy Deficiency in Sport (RED-S), a condition caused by insufficient energy intake to meet training demands, could be exacerbated by such drug use. The potential link to eating disorders has been emphasized by Professor Lars Engebretsen, chair of WADA’s Health, Medical & Research Committee, who highlights the risk that wider use of weight-loss drugs could negatively impact athletes struggling with body image issues.

Currently, nine weight-loss substances are banned by WADA, but semaglutide and tirzepatide have not yet met the criteria for prohibition, which requires evidence of performance enhancement, health risks, and violation of the spirit of sport. Researchers emphasize the need for further investigation into the drugs’ effects on athletes, alongside education and monitoring efforts to safeguard athlete welfare.

Although the use of these medications by elite athletes appears to be increasing, decisions regarding their status within anti-doping regulations will depend on forthcoming evidence and deliberations by the international sports community.