SURMOUNT-5 Trial: Key Findings Explained in Plain Language
In the first head-to-head comparison, tirzepatide produced 47% more weight loss than semaglutide (Ozempic/Wegovy) over 72 weeks.
Study overview
Conducted by
Eli Lilly, multi-center international trial
Patients
751 adults with obesity (BMI 30+) without diabetes
Duration
72 weeks
Published in
New England Journal of Medicine
Year
2024
Key findings
20.2% weight loss with tirzepatide vs 13.7% with semaglutide
At maximum tolerated doses, tirzepatide outperformed semaglutide by 47% in relative weight reduction. This was the first direct comparison in a randomized trial.
More patients achieved 20%+ weight loss on tirzepatide
Approximately 1 in 3 tirzepatide patients lost over 25% of their body weight, compared to roughly 1 in 10 on semaglutide.
Similar side effect profiles
Both drugs had comparable rates of nausea, diarrhea, and other GI side effects. The additional weight loss from tirzepatide didn't come at the cost of more side effects.
Tirzepatide reached maximum dose faster
The titration schedule for tirzepatide allowed patients to reach their maximum dose sooner, which contributed to earlier onset of full efficacy.
What this means for you
This trial settled the debate. Tirzepatide's dual GIP/GLP-1 mechanism delivers meaningfully more weight loss than GLP-1-only drugs like semaglutide. For a 230 lb person, that's approximately 46.5 lbs lost on tirzepatide vs 31.5 lbs on semaglutide -- a 15 lb difference.
Limitations
The trial used maximum tolerated doses of each drug, which may not reflect real-world dosing patterns. Follow-up was 72 weeks; longer comparisons may show different patterns. The study did not include patients with type 2 diabetes.
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