A revolution in weight loss is apparently underway. It started in 2021, when the FDA approved the diabetes drug semaglutide for weight loss. The weekly injectable—sold under the brand name Wegovy—can help users lose 5 to 10 percent of their body weight, leading commentators to describe the drug as both a “medical breakthrough” and a “silver bullet” for obesity. Elon Musk says he’s taking it, Kim Kardashian is rumored to be using it, and everyone from Hollywood to the Hamptons reportedly wants a prescription.