Retatrutide
/ Triple agonist of GIP, GLP-1, and glucagon receptorsALIAS · LY3437943
Terms in this page you can click for a plain-English popup: , , , , , , , .
Investigational. Phase 2 data reported the largest weight-loss effect for a GLP-1-class agent at time of publication. Phase 3 TRIUMPH program results continue to report through 2026.
Retatrutide is a single-molecule triple agonist of the GIP receptor, GLP-1 receptor, and glucagon receptor. The glucagon-receptor component is hypothesized to add hepatic fat mobilization and energy expenditure on top of the incretin-mediated weight-loss mechanisms. 39-amino-acid acylated peptide with a half-life supporting weekly subcutaneous dosing.
Phase 2 obesity data (Jastreboff 2023) reported the largest weight-loss effect for any GLP-1-class agent at time of publication. Phase 3 TRIUMPH program with CV outcomes, obesity, T2DM, and MASH indications is ongoing. No FDA or EMA authorization as of April 2026.
Dose-dependent GI adverse events (nausea up to ~49% at 12 mg), small heart-rate increases (+6-11 bpm), mild transient transaminase elevations. No unexpected hepatic or cardiovascular signals in Phase 2. Class warnings for MTC/MEN2 applied in trials.
Regulatory status
- FDA status:
- Investigational (Phase 3)
- Compounding:
- Not eligible for compounding (approved, not in shortage)
Retatrutide is not a marketed drug. The API is not available through legitimate pharmaceutical supply chains. FDA has issued import alerts and warning letters to online sellers of "research-grade" retatrutide; products sold online are not FDA-reviewed and have been associated with identity and purity failures in third-party assays.