Phase 2 retatrutide data shows greater mean weight loss than Phase 3 tirzepatide data. Phase 3 retatrutide results are pending.
Updated: June 1, 2026 · Editorial review: GLP-1 Price Guide Editorial Team · Pricing verified: June 1, 2026
| Factor | Tirzepatide (Zepbound) | Retatrutide (investigational) |
|---|---|---|
| Receptors | GLP-1 + GIP (dual) | GLP-1 + GIP + glucagon (triple) |
| Phase | Marketed (FDA-approved) | Phase 3 (TRIUMPH program) |
| Mean weight loss (high dose) | ~22% at 72 weeks (SURMOUNT-1) | ~24% at 48 weeks (Phase 2) |
| Commercial availability | Yes (FDA-approved Zepbound) | No (clinical trials only) |
Phase 3 retatrutide data is not yet published. If Phase 3 readouts support Phase 2 efficacy and safety, FDA submission is projected 2026-2027 with potential approval 2027-2028.