Tirzepatide produced greater average weight loss than semaglutide in SURMOUNT-5, a direct randomized comparison. The useful follow-up is not simply “which wins?” It is whether the trial answers the question you are bringing to a clinician—and whether a provider’s advertised product is the one the study tested.
The direct comparison
SURMOUNT-5 assigned 751 adults with obesity, without type 2 diabetes, to weekly injections of tirzepatide or semaglutide for 72 weeks. The trial was open-label: treatment assignment was known. It compared maximum tolerated doses of tirzepatide 10 or 15 mg with semaglutide 1.7 or 2.4 mg. The study was funded by Eli Lilly. [1]
At week 72, estimated average weight change was −20.2% with tirzepatide and −13.7% with semaglutide. The difference is 6.5 percentage points of starting body weight. It is not a promise that every person would lose 6.5 percentage points more after switching. The trial also favored tirzepatide for average waist reduction. [1]
Why a head-to-head trial matters
Putting two drugs in the same randomized study makes the comparison more informative than placing the headline from one trial next to the headline from another. Different study populations, follow-up periods and ways of handling missing data can make cross-trial comparisons misleading. Our guide to reading weight-loss trials gives you a short checklist for recognizing those differences.
Open-label design is still a limitation worth recognizing: people and care teams knew the assignment. A group average also hides the range of individual experiences. Treat the result as evidence to discuss, rather than a personal target or a guarantee that the highest trial dose is appropriate for you.
The safety result belongs beside the weight result
Gastrointestinal adverse events were the most common in both groups. Most were mild or moderate and occurred mainly during dose escalation. That description does not establish that either medication is the safer choice for a particular person. [1]
Before choosing a service, find out how clinical questions are handled between visits and who reviews problems with tolerability. Our provider support guide focuses on these practical details. The right place to discuss contraindications, interactions, prior treatment and individual risks is an appointment with the prescriber, not a comparison score.
The result does not transfer to every product
This study compared specified weekly injections. It was not a test of oral products, compounded preparations or telehealth companies. If an advertisement borrows the headline, compare the actual formulation and treatment route with the study before assuming the same evidence applies.
FDA does not approve compounded drugs or assess their safety, effectiveness and quality before marketing. Our approved-versus-compounded guide explains why a familiar ingredient name alone is insufficient. [2]
Compare the care arrangement separately
Once a clinician has discussed appropriate options, the remaining consumer questions are concrete: what product is being prescribed, which pharmacy fills it, what will you pay, and how will follow-up work? A drug trial cannot tell you which company has the clearest billing terms or the most responsive support team.
Use our insurance and prior-authorization guide to establish the coverage assumptions, then compare the full-year bill with the cost tool. A larger average effect in a trial does not remove the need for an affordable, clinically appropriate plan you can discuss and follow.