Compare · 6 min read
Sema, Tirz or Reta?
Three generations of weight-loss peptides, side by side.
Semaglutide, tirzepatide and retatrutide are the three big names in weight management. They share a lot — all once weekly, all built up slowly — but each adds something the last one lacked.
| Semaglutide | Tirzepatide | Retatrutide | |
|---|---|---|---|
| Acts on | GLP-1 | GLP-1 + GIP | GLP-1 + GIP + glucagon |
| Taken | Once weekly | Once weekly | Once weekly |
| Trial weight loss* | ~15% | ~20% | ~24% (phase 2) |
| Stomach side effects | Common | Common | More pronounced |
| Status | Approved (Ozempic®/Wegovy®) | Approved (Mounjaro®/Zepbound®) | Investigational |
*Average at the highest studied dose in the main trials, over 48–72 weeks. Individual results vary widely.
How to think about it
- Semaglutide — the most familiar, the longest track record.
- Tirzepatide — usually more effect, with a similar side-effect pattern.
- Retatrutide — the strongest results so far, but the newest and the hardest on the stomach.
Whichever one, the rules are the same: start low, climb slowly, and hold at a step for as long as you need. Want to talk through which fits you? Ask.