Serena Williams says she has lost weight using GLP-1 medication. The drugs help manage blood sugar and promote weight loss, they come with likely side effects.

In a recent video spot, the 43-year-old athlete reveals that Ro helped her lose 31 pounds in eight months. “Yes, I’m on Ro. They say GLP-1s for weight loss is a shortcut. It’s not, it’s science. After kids, it’s a medicine my body needed,” she says.