Tirzepatide vs Semaglutide
Two of the most effective weight-loss medications available. Here is how they differ — mechanism, results, side effects — so you and your provider can choose.
Last reviewed 2026-10-04 by Lauren Orta, FNP-C, Family Nurse Practitioner. This page is clinical content and is reviewed on a regular schedule.
| Factor | Tirzepatide | Semaglutide |
|---|---|---|
| Mechanism | Dual GLP-1 + GIP receptor agonist | GLP-1 receptor agonist |
| Route | Subcutaneous injection | Injection (and oral form available) |
| Head-to-head result | 20.2% average weight loss at 72 weeks (SURMOUNT-5) | 13.7% average weight loss at 72 weeks (SURMOUNT-5) |
| GI side-effect profile | More diarrhea, less nausea | More nausea, more constipation |
| Best fit | Men seeking the greatest average weight loss | Men who prefer an oral option or have more CV outcome data |
How they work
Semaglutide is a GLP-1 receptor agonist — it mimics the hormone that signals fullness and slows stomach emptying. Tirzepatide goes further: it is a dual GIP and GLP-1 receptor agonist, targeting two incretin pathways at once. That dual action is the leading explanation for the greater average weight loss seen in head-to-head trials. Both suppress appetite and reduce "food noise," and both are taken on a gradual titration schedule to manage gastrointestinal side effects.
What the SURMOUNT-5 trial showed
The SURMOUNT-5 trial (published in the New England Journal of Medicine, 2025) is the head-to-head comparison. On average, participants lost about 20.2% of body weight on tirzepatide versus 13.7% on semaglutide over 72 weeks — roughly 50 lbs versus 33 lbs. About 1 in 3 tirzepatide patients achieved 25% or greater weight loss, versus about 1 in 6 on semaglutide. Tirzepatide was superior on all five key secondary endpoints. Individual results vary, and weight loss in both groups was somewhat lower in men than women.
Source: Aronne LJ, et al. Tirzepatide as Compared with Semaglutide for the Treatment of Obesity (SURMOUNT-5). N Engl J Med. 2025;393(1):26–36.
Side-effect differences
Both are gastrointestinal. Semaglutide tends toward nausea and constipation; tirzepatide more commonly causes diarrhea with less nausea. Side effects are dose-dependent and usually worst during titration and after dose increases. Both carry a warning for men with a personal or family history of medullary thyroid carcinoma or MEN 2.
How to choose
This is not as simple as "tirzepatide wins." Semaglutide has a larger long-term cardiovascular outcomes dataset (the SELECT trial) and an oral form, which some men prefer. Tirzepatide produces greater average weight loss and is often better tolerated. The right choice depends on your weight-loss goal, your tolerance for GI side effects, your cardiovascular history, and whether an oral option matters to you. Your provider helps you decide based on your actual situation. Tirzepatide is a separate standalone product at A2Z, priced independently from the $149/mo TRT program.
Talk to a provider about medical weight loss
A free video consult, comprehensive labs, and an honest recommendation — tirzepatide, semaglutide, or neither. Your numbers and goals decide, never a generic menu.