Serena Williams has openly spoken up about her weight loss struggle after the birth of her second daughter in 2023. As she returns to competitive tennis at the age of 44, discussion around her much leaner appearance was sparked again. Williams has been candid about attributing her weight loss to a GLP-1 drug called Zepbound. Serena Williams Lost 34 Pounds With Zepbound As Serena Williams made a high-profile return to singles competition at Wimbledon on June 30, fans did not miss the difference in her physique. In 2025, Williams revealed that she was able to shed about 34 to 38 pounds (15 to 17 kg) with the help of the prescription GLP-1 medication Zepbound (tirzepatide), alongside regular exercise and healthy eating. Her comeback to the sport also sparked debate over whether GLP-1 medications provide a competitive advantage and if they should be banned. But as of now, GLP-1 drugs are not banned by the anti-doping authorities. She also emphasized that the medication was an addition to, not a replacement for her existing fitness habits. According to NBC, she announced a partnership with the company Ro, which prescribes GLP-1 medications through telehealth. Also read: Did Donald Trump Take Eli Lilly's Weight Loss Drug? What Did White House Say The RO website features Williams, stating: “After kids, she was doing everything right, but nothing worked. Ro finally helped her get back to her strongest self," it says. "After losing weight with another GLP-1 provider, Serena chose Ro to continue her weight loss journey. She has used both branded vials and pens.” In a conversation with People that her weight struggle began after the birth of her daughter. She said that she was not able to get to the weight she wanted regardless of her efforts. She said, “It was crazy because I'd never been in a place like that in my life where I worked so hard, ate so healthy, and could never get down to where I needed to be at.” Apart from weight loss, she also spoke about other benefits she experienced after starting Zepbound. She said, “I just can do more. I'm more active. My joints don't hurt as much. I just feel like something as simple as just getting down is a lot easier for me. And I do it a lot faster. I feel like I have a lot of energy, and it's great. I just feel pretty good about it.” What Is Zepbound And How It Is Different From Ozempic? Zepbound’s active ingredient is tirzepatide. While it is called GLP-1 medication, it is more than that. It mirrors two hormones that your body naturally releases after you eat: GLP-1 (Glucagon-Like Peptide-1) This hormone makes you feel full sooner, slows stomach emptying, so food stays in your stomach longer, reducing appetite. It also helps the pancreas release insulin when blood sugar rises. GIP (Glucose-Dependent Insulinotropic Polypeptide) This improves insulin response, enhances metabolism, and works together with GLP-1 to produce greater weight loss than GLP-1 alone. Zepbound's two-way action is the biggest factor that distinguishes it from Ozempic. The latter mimics only one hormone, GLP 1, which reduces appetite and hunger by promoting a feeling of fullness. Zepbound, on the other hand, performs the function of GLP-1 while also improving insulin sensitivity and fat metabolism effectively.