Eli Lilly reported topline phase-3 results for retatrutide on April 15, 2026, showing mean weight reductions of 22–24% at the 12 mg dose over 68 weeks in adults with obesity without diabetes. The data are roughly comparable to tirzepatide 15 mg in SURMOUNT-1 but with a steeper dose-response curve.
Retatrutide is a triple agonist of the GLP-1, GIP, and glucagon receptors. The glucagon component is thought to drive additional energy expenditure on top of the appetite-suppressing GLP-1/GIP effects — though it also increases the gastrointestinal AE profile and required slower dose-titration than tirzepatide in the trials.
Lilly indicated it will submit a New Drug Application to FDA in late 2026, with potential approval in 2027. The drug is not currently available either as a brand-name product or via compounding pathways.