Eli Lilly's Zepbound Shows Superior Weight Loss Results

Eli Lilly announced on Wednesday that its weight-loss medication, Zepbound (tirzepatide), demonstrated superior efficacy over Novo Nordisk's (NYSE:NVO) Wegovy (semaglutide) in the phase 3b SURMOUNT-5 trial, with an average weight loss of 20.2% compared to Wegovy's 13.7%.

The trial targeted adults with obesity or overweight who had at least one weight-related medical condition but did not have diabetes. Zepbound outperformed Wegovy across both the primary and all five key secondary endpoints at 72 weeks.

Notably, 31.6% of participants on Zepbound achieved at least a 25% reduction in body weight, while only 16.1% of Wegovy users achieved the same, as indicated by Eli Lilly (NYSE:LLY).

Leonard Glass, Eli Lilly's senior vice president of global medical affairs, expressed excitement about the findings, citing that Zepbound provided 47% more relative weight loss than Wegovy. He highlighted that Zepbound's unique dual GIP and GLP-1 receptor agonist mechanism offers transformative benefits to patients.

The safety profile of Zepbound was reaffirmed, aligning with previous SURMOUNT studies; the most common side effects for both medications were mild to moderate gastrointestinal issues.

Lilly plans to publish the results in a peer-reviewed journal and present them at a medical meeting next year. Zepbound is already FDA-approved for obesity and overweight management in the U.S.

This announcement strengthens Eli Lilly's position in the growing obesity treatment market, where demand for effective weight-loss therapies continues to rise.

Analysts at Morgan Stanley (NYSE:MS) reacted positively, viewing the update as incrementally beneficial for LLY shares. They reiterated an Overweight rating, suggesting that the results endorse Zepbound’s low-20s percent weight loss profile, while noting supply constraints may remain a concern for both companies.