Tirzepatide outperforms semaglutide for weight loss in the first head-to-head obesity trial
Over 72 weeks, adults without diabetes lost an average of 20.2% on tirzepatide versus 13.7% on semaglutide.
The SURMOUNT-5 trial, published May 11, 2025 in the New England Journal of Medicine, randomized 751 adults with obesity but without type 2 diabetes to tirzepatide or semaglutide at the maximum tolerated dose.
At 72 weeks the average weight change was -20.2% with tirzepatide and -13.7% with semaglutide. Waist circumference fell by 18.4 cm and 13.0 cm. Gastrointestinal events were the most common adverse events in both groups.
The trial was open-label and funded by the maker of tirzepatide, and averages hide wide individual variation.
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