Why two names for the same drug?

Whether you’re a fan of the drug name Zepbound or, like one X user, think it sounds like “an off brand bus line,” you’re likely to have some opinion about the new moniker for Eli Lilly’s blockbuster diabetes drug Mounjaro. The company announced the new name on Nov. 8 following the Food and Drug Administration’s approval of the drug for weight loss as well.

Zepbound and Mounjaro are the exact same medication, tirzepatide, with the same strength — unlike Ozempic and Wegovy, the Novo Nordisk competitors marketed for type 2 diabetes and weight loss respectively, which have different strengths. Meanwhile, on Nov. 9, the European Medicines Agency also issued a positive recommendation to add the weight loss indication to Mounjaro — no new name required.

Exactly why Eli Lilly chose Zepbound remains a mystery, as the company declined to provide details about the naming process. But experts tell STAT that the drug name offers important insights into the marketing differences between the U.S. and Europe, as well as the difficult work of attempting to create a distinctive and evocative brand identity.