Serena Williams’ weight-loss drug could be banned in tennis, predicts British icon

Richie Mills 16 Jun 2026 11:00 AM

Serena Willliams in action

Greg Rusedski believes that weight loss drugs – like the one Serena Williams has taken for her WTA Tour comeback – will be “banned” in the future.

Last August, Serena discussed shedding 31lbs (2.21 stone) thanks to taking a GLP-1 weight-loss drug, the most famous of which are Ozempic, Wegovy, and Zepbound. These were initially designed to treat diabetes but can also help with weight loss.

The 23-time major winner, who has taken Zepbound herself, has a partnership with a telehealth service called Ro – a company on whose board her husband, Alexis Ohanian, sits.

The American said on Oprah Winfrey’s podcast that same month that her joints were “so much lighter” following her weight loss but stressed that she had exhausted every avenue when trying to slim down.

“I couldn’t beat the weight. It was the one opponent I couldn’t beat,” said Serena, who made her comeback to the WTA Tour at Queen’s Club last week after nearly four years away.

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According to The Athletic, anti-doping authorities, such as the World Anti-Doping Agency (WADA), have been monitoring GLP-1 drugs but right now, they are not a prohibited substance, nor are they classed as a performance-enhancing drug.

The report adds that the two main GLP-1 drugs, Semaglutides and tirzepatides, have been on WADA’s watchlist since 2024. They work by triggering the pancreas to release insulin and slow digestion, along with reducing one’s appetite and hunger.

Now, former British No 1 Rusedski has had his say on the matter. Giovanni Mpetshi Perricard’s coach said he was “quite surprised” WADA hadn’t taken action on these weight-loss drugs, while stressing Serena has done nothing wrong.

He said on the latest episode of Off Court With Greg Rusedski, “We’ve talked about the weight loss drugs. Right now, they are not banned; they are legal to take. She’s not breaking anything but WADA is looking into this because they are thinking, ‘This might be a slight unfair advantage’.

“If you can take a pill, get your body weight down to a certain extent and some players might use it to thin out very quickly because they want to get their weight ratio. I think it will be banned in time but at the moment Serena is doing absolutely nothing wrong.”

Rusedski, who added it was “great” to have Serena back in the sport, also wasn’t buying the notion that these weight-loss drugs may inhibit you in a muscular sense.

He added, “I think it takes away some of your muscle, but if you’re training hard enough you are going to be able to get the muscle but you can’t have that sort of weight loss that quickly because it basically makes your stomach shrink.

“You don’t have that urge to eat so it gives you a little bit of an advantage. There’s a lot of question marks about what is and isn’t legal and what is and isn’t ethical.”

Serena’s decision to promote her weight-loss drug in a Super Bowl advert sparked a big debate about the topic. And for Rusedski, this means WADA has a “tricky balance” to find when it comes to how players use these drugs and sponsorship of them.

Months before her comeback, Serena told Oprah, “I wish I had done this while I was still playing. It would have made such a big difference for me and my career.”

Now she’s back, this thorny issue may continue to rumble on.