Serena Williams’ rumored return to professional tennis has triggered a broader conversation about a topic that has been building in sports medicine circles for two years: the use of GLP-1 drugs – the class of medications that includes Ozempic and Wegovy – by elite athletes for body composition changes. Williams, who retired from professional tennis in 2022 and has been publicly open about her post-retirement body transformation journey, is reported to be considering a limited comeback, and observers have noted her physical transformation as part of the discussion around what these drugs might mean for performance sport.

The New York Times reported on the ‘coming reckoning’ that sports governing bodies, anti-doping agencies, and athlete organizations will face as GLP-1 adoption spreads further into elite athletic circles. The drugs are currently legal in sport – they are not on the World Anti-Doping Agency’s prohibited list – but the performance implications of medications that alter body composition, appetite regulation, and potentially metabolism create questions that sports administrators have not yet fully addressed.

What GLP-1 Drugs Actually Do to the Body

GLP-1 receptor agonists work by mimicking a hormone naturally produced in the gut that regulates appetite, insulin secretion, and gastric emptying. In practical terms, they make users feel full more quickly, reduce food cravings, and slow the rate at which the stomach empties after meals. The result is significant caloric reduction without the constant hunger that makes traditional dieting so difficult to sustain.

For athletes, the implications depend heavily on the sport and the athlete’s specific situation. In weight-class sports like wrestling, boxing, and weightlifting, rapid weight loss drugs have always been a concern because athletes use them to cut weight before weigh-ins. GLP-1 drugs are slower-acting and produce more gradual weight loss, but the same fundamental concern applies. In endurance sports, reduced body weight can improve power-to-weight ratios that directly affect performance.

• WADA has not placed GLP-1 drugs on its prohibited list and has not indicated imminent plans to do so.
• The drugs are FDA-approved medications with legitimate medical uses, making blanket prohibition difficult to justify ethically.
• Long-term effects of GLP-1 drugs on athletic performance, muscle preservation, and cardiovascular function in elite athletes are not yet well-studied.
• The ‘peptide bros’ culture documented in Business Insider involves athletes and fitness enthusiasts using these and similar drugs for body composition benefits that blur the line between medical use and performance enhancement.

Williams and the Broader Question

The discussion around Serena Williams is notable partly because she is one of the most prominent athletes in the world and partly because her potential comeback at age 44 would be historically unprecedented in professional tennis. Her physical conditioning as she approaches a possible return has been widely noted, and the conversation about what tools – including pharmaceutical ones – she might be using is both natural and illustrative of a broader cultural shift in how we think about body transformation and performance optimization.

Frequently Asked Questions

Are GLP-1 drugs banned in professional tennis?

No. GLP-1 drugs are not on the WADA prohibited list and are permitted in professional tennis as of 2026. Athletes using them for legitimate medical purposes (diabetes, obesity) are not required to disclose this use.

What is the difference between Ozempic and Wegovy?

Both contain semaglutide (the active GLP-1 ingredient), but they are different products at different doses. Ozempic is approved for diabetes management. Wegovy is approved for chronic weight management and typically uses a higher dose.