Tirzepatide vs Semaglutide vs Retatrutide
The short answer: in clinical trials, retatrutide produced the highest weight loss, tirzepatide is the strongest option that is FDA approved, and semaglutide has the longest safety record. Which one fits depends on how aggressive, and how proven, you want to be.
| Compound | Mechanism | Trial weight loss | Status |
|---|---|---|---|
| Semaglutide | GLP-1 | ~15 to 20% | Approved (Ozempic, Wegovy) |
| Tirzepatide | GLP-1 + GIP | ~20 to 26% | Approved (Mounjaro, Zepbound) |
| Retatrutide | GLP-1 + GIP + glucagon | up to ~24% | Phase 3 ongoing, not approved |
Semaglutide: the proven one
Semaglutide mimics the GLP-1 hormone to reduce appetite, slow digestion, and steady blood sugar. It is the molecule behind Ozempic and Wegovy, and it carries the largest body of clinical and real-world data of the three. In the STEP trials it produced roughly 15 percent body-weight loss. If a long track record matters most, this is the benchmark.
Tirzepatide: the strongest approved option
Tirzepatide adds a second receptor, GIP, on top of GLP-1. That dual action drove up to roughly 21 percent weight loss in the SURMOUNT-1 trial, and it beat semaglutide directly in the SURMOUNT-5 head-to-head. It is the same molecule as Mounjaro and Zepbound, so it pairs strong results with FDA approval. For most people comparing these, tirzepatide is the sweet spot of power and proof.
Retatrutide: the most powerful, least proven
Retatrutide adds a third target, glucagon, which raises energy expenditure alongside appetite control. A Phase 2 trial published in the New England Journal of Medicine recorded up to roughly 24 percent, the highest of any of these compounds so far. The catch: it is not approved yet, so it sits at the cutting edge of research. Strongest on paper, but the thinnest safety record.
Which should you choose?
If you want the most data behind you, semaglutide. If you want the strongest results with approval already in place, tirzepatide. If you are tracking the frontier and accept that it is unproven, retatrutide. Whatever the choice, the rule that does not change is verification: confirm purity and identity with a batch-specific COA before anything else.
One thing not to do: stack them. They act on overlapping receptors, so combining raises side-effect risk without a clear benefit. Pick one and titrate slowly.
All three, verified by batch
HPLC purity and mass-spec identity, with a COA on every order.
See the catalogFAQ
Is retatrutide stronger than tirzepatide?
In trials, retatrutide showed higher weight loss. But it is still Phase 3 and not approved, while tirzepatide is FDA approved. Stronger on paper does not mean more proven.
Can you stack these together?
No. They act on overlapping receptors, so combining them raises side-effect risk without a clear benefit. Researchers pick one and titrate.
Which has the longest safety record?
Semaglutide, by a wide margin, as the molecule behind Ozempic and Wegovy.