Retatrutide is an investigational triple agonist that activates GLP-1, GIP and glucagon receptors simultaneously. Late-stage trials put it near 28% body-weight loss, the largest figures reported for any weight-loss compound tested in humans. It is not FDA-approved: Phase 3 TRIUMPH is still reading out and no NDA has been filed.
- Hits three receptors at once: GLP-1R for appetite, GIPR for insulin and fat, and GcgR for thermogenesis and hepatic fat.PubMed: Retatrutide
- TRIUMPH-1 (obesity, 80 weeks): 28.3% weight loss at the highest trial dose, rising to 30.3% at 104 weeks, with 45.3% of participants losing at least 30% of body weight, a surgical-level result.TRIUMPH-1 (Phase 3, 80 wks)
- TRIUMPH-4 (obesity plus knee osteoarthritis, 68 weeks): 28.7% at the top dose and 26.4% one step below it.TRIUMPH-4 (Phase 3, 68 wks)
- TRANSCEND-T2D-1 in diabetes reported A1c down 2.0 points alongside 16.8% weight loss.TRANSCEND-T2D-1, Lancet Jun 2026
- Phase 3 surfaced a dose-dependent abnormal-skin-sensation signal that was not seen in Phase 2.Phase 3 TRIUMPH warnings