Side-by-side
| Semaglutide | Tirzepatide | Retatrutide | |
|---|---|---|---|
| Class | GLP-1 agonist | GLP-1/GIP dual | GLP-1/GIP/glucagon triple |
| Trial weight loss | ~15% (STEP 1, 68 wk) | ~21% (SURMOUNT-1, 72 wk) | ~24% (Phase 2, 48 wk) |
| FDA status | Approved 2017/2021 | Approved 2022/2023 | Phase 3 |
| Dosing | Weekly SC, 2.4 mg max | Weekly SC, 15 mg max | Weekly SC |
| Half-life | ~1 week | ~5 days | ~6 days |
Mechanism evolution
Each generation adds a receptor to address different aspects of metabolic regulation. Glucagon receptor (retatrutide-specific) adds energy expenditure beyond appetite reduction.
When will retatrutide be approved?
Phase 3 results expected 2026, approval likely 2027-2028.