Compared, cited
Semaglutide vs Tirzepatide
Both are once-weekly injectables for blood sugar and weight. Tirzepatide activates two gut-hormone receptors; semaglutide activates one. In the only head-to-head weight-loss trial, tirzepatide produced more average weight loss. Here is the cited picture.
Last updated August 2026
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| At a glance | Semaglutide | Tirzepatide |
|---|---|---|
| Receptors | GLP-1 only | GLP-1 + GIP (dual) |
| Brand names | Ozempic, Wegovy, Rybelsus | Mounjaro, Zepbound |
| Half-life | ~7 days | ~5 days |
| Approved max dose | 2 mg (Ozempic) / 2.4 mg (Wegovy) weekly | 15 mg weekly |
| Head-to-head weight loss | -13.7% average (SURMOUNT-5, 72 wk) | -20.2% average (SURMOUNT-5, 72 wk) |
| Status | FDA-approved | FDA-approved |
How they work
Semaglutide mimics one gut hormone, GLP-1, which raises insulin when blood sugar is high, slows the stomach, and reduces appetite. Tirzepatide mimics GLP-1 and a second hormone, GIP, at the same time. That dual action is the leading explanation for why tirzepatide has generally produced greater average weight loss.
What the head-to-head trial showed
SURMOUNT-5 (New England Journal of Medicine, 2025) randomized 751 adults with obesity and no diabetes and treated them for 72 weeks at the maximum tolerated dose. Tirzepatide produced -20.2% average body-weight change versus -13.7% for semaglutide, a statistically significant difference. These are averages across a trial population - individual results vary, and the figure is mean percent change from baseline, not a guaranteed personal outcome.
Approval, brands, and safety
Both are FDA-approved, sold under different brand names for different approved uses (see Ozempic vs Wegovy and Mounjaro vs Zepbound). Both share the same major cautions on their labels - a contraindication with a personal or family history of medullary thyroid carcinoma or MEN 2, and a pancreatitis warning - and both most commonly cause gastrointestinal side effects. The cited specifics are on each compound page.
Who fits which
Where semaglutide fits
It is widely prescribed, some people tolerate it better, and it is the only one of the two with an oral form (Rybelsus, for diabetes). This is a prescriber's decision, not a self-selection.
Where tirzepatide fits
It produced greater average weight loss in the head-to-head trial and has a higher dose ceiling. Again, which drug is appropriate is a clinical decision based on the person and the indication.
The cited card
Semaglutide
GLP-1 agonist
The cited card
Tirzepatide
GLP-1 / GIP dual agonist
Questions people ask
Is tirzepatide better than semaglutide for weight loss?
In the one head-to-head trial (SURMOUNT-5), tirzepatide produced more average weight loss - about 20% versus 14% at 72 weeks. But that is an average, individual response and tolerance vary, and which drug is right is a prescriber's decision. This is educational information, not medical advice.
What is the actual difference between semaglutide and tirzepatide?
Semaglutide activates one gut-hormone receptor (GLP-1); tirzepatide activates two (GLP-1 and GIP). They are sold under different brand names and reach different maximum doses.
Are these the same as Ozempic, Wegovy, Mounjaro, and Zepbound?
Yes. Ozempic, Wegovy, and Rybelsus are all semaglutide. Mounjaro and Zepbound are both tirzepatide. The brands differ by approved use and dose, not molecule.
Sources
- [1]Tirzepatide as Compared with Semaglutide for the Treatment of Obesity (SURMOUNT-5), NEJM 2025Head-to-head: tirzepatide -20.2% vs semaglutide -13.7% mean weight loss at 72 weeks.
Full cited data for each compound is on its library page, linked above. Weight-loss figures are trial averages; individual results vary.
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