Serena Williams' highly anticipated return to professional tennis has generated excitement across the sporting world, but it has also reignited discussions about the use of GLP-1 medications in elite competition.
The 23-time Grand Slam champion is set to make her comeback at the Queen's Club Championships, nearly four years after stepping away from the sport. At 44 years old, Williams will return as one of the most accomplished athletes in tennis history, but her comeback arrives amid growing scrutiny of a medication she has openly credited for improving her health and fitness.
Williams has publicly revealed that she uses Zepbound, a GLP-1 medication commonly prescribed for weight management. She became a brand ambassador for telehealth company Ro in 2025 and has spoken extensively about the benefits she experienced after taking the drug, including weight loss, improved cholesterol levels and better overall health. According to Williams, she lost around 34 pounds and now feels healthier than she did during parts of her playing career.
Her return to competition has naturally led to questions about whether athletes can legally use medications such as Zepbound, Ozempic and Wegovy while competing professionally.
Under current regulations, the answer is yes.
The World Anti-Doping Agency (WADA) does not prohibit GLP-1 medications. Although drugs such as semaglutide and tirzepatide are being monitored by WADA, they are not included on the organisation's prohibited substances list. As a result, Williams would not be required to stop taking Zepbound in order to compete on the WTA Tour.
The debate, however, extends beyond legality.
Researchers and sports scientists continue to study whether GLP-1 medications could affect athletic performance. There is currently no evidence that they provide a direct performance-enhancing advantage to healthy athletes. In fact, some experts have pointed to potential drawbacks, including reduced calorie intake, slower recovery, fatigue and possible muscle loss if not carefully managed.
For elite athletes such as Williams, those risks can be mitigated through carefully structured nutrition plans, strength training programmes and close medical supervision. Even so, the growing popularity of GLP-1 drugs has prompted WADA to keep a close watch on their use across multiple sports.
Williams has consistently defended her decision to use the medication, explaining that she turned to GLP-1 treatment after struggling to lose weight following pregnancy despite maintaining an intense training routine and healthy lifestyle. She has also advocated for greater transparency and reduced stigma surrounding the use of weight-management treatments.
Whether her comeback leads to a sustained return at the highest level remains to be seen. What is certain is that Williams' reappearance on the tour has created two major talking points: the return of one of tennis' greatest champions and a broader conversation about how modern medicine fits into the future of professional sport.
