Tirzepatide vs. semaglutide: what SURMOUNT-5 compared

Two weight-loss percentages from two separate headlines can look like a direct comparison even when the studies enrolled different people and followed them for different lengths of time. SURMOUNT-5 asked the comparison within one randomized trial.

What the trial found

The 2025 study randomized 751 adults with obesity without type 2 diabetes to tirzepatide or semaglutide. It was open-label, meaning treatment assignment was known. At 72 weeks, the reported mean body-weight change was a reduction of 20.2% with tirzepatide and 13.7% with semaglutide. Gastrointestinal events were the most common adverse events in both groups. Eli Lilly funded the trial.

Those numbers describe the study's treatment groups. They are not a prediction of what any one reader will experience.

Why the shared study setting helps

A head-to-head design gives you a better starting point than constructing a competition from unrelated trials. You can examine a common eligibility framework, follow-up period, and analysis plan instead of trying to reconcile several different designs first.

That does not remove every judgment. Read how treatments were used, how missing observations were handled, and what happened when participants stopped treatment. Keep the open-label design in your notes when weighing the findings.

An average is one part of a decision

A treatment conversation can involve several goals. Ask which outcomes matter in your situation and how they would be assessed. A body-weight average alone cannot tell you which option you could tolerate, access, or continue using under medical supervision.

It also cannot answer every question about long-term outcomes. Write down what the trial measured rather than attaching extra promises to the result. “More weight loss in this comparison” is a more precise statement than “better for everyone.”

Use the paper to sharpen the next question

Bring the study title and a short list of priorities to a prescribing clinician. Ask how the participant population relates to you, which alternatives deserve consideration, and what follow-up would be needed. If the discussion involves a specific product, pair the trial with our GLP-1 label guide so the ingredient and dispensed preparation stay in view.