It’s rare to find a product so successful that its makers stop advertising it. But that’s what happened to the weight-loss drug Wegovy in May. In the United States, where prescription drugs can be advertised, developer Novo Nordisk pulled its television adverts because it couldn’t keep up with demand.

The injectable medication, called semaglutide, works by imitating a hormone that curbs appetite and was approved as an obesity treatment by the US Food and Drug Administration (FDA) in 2021. In a study, participants who took semaglutide for over a year lost more than twice as much body weight on average — almost 16% — as did people taking an older weight-loss drug that mimics the same hormone1.

Semaglutide’s approval for treatment of weight loss came four years after the drug was approved for type 2 diabetes under the trade name Ozempic, also made by Novo Nordisk, based in Bagsværd, Denmark. Demand for Ozempic has skyrocketed as physicians prescribe it for weight loss outside its approved use.

Nature 620, 28-30 (2023)