Retatrutide

Status

In trials. Investigational. It is in Phase 3 (the TRIUMPH program); it is not FDA-approved, and no approval elsewhere is listed in this entry's sources.

What it is

A triple agonist — one 39-amino-acid peptide engaging GLP-1, GIP and glucagon receptors. The glucagon arm is what separates it from tirzepatide's dual design.

What published research measured

The Phase 2 obesity trial (Jastreboff et al., NEJM 2023) reported 24.2% mean weight loss at 48 weeks on its highest arm. Full Phase 3 obesity and type 2 diabetes readouts landed in 2026; the cardiovascular outcomes trial (TRIUMPH-3) reads out in 2027. Cross-trial comparisons with other drugs are unreliable.

Source

NEJM, Jastreboff et al. 2023; TRIUMPH Phase 3 program

Sources

• Half-life source for Retatrutide
• Lilly reports retatrutide results in a type 2 diabetes comparison trial (2026-10-28)