Retatrutide (LY3437943)

Retatrutide is a 39-amino acid synthetic peptide engineered from a GIP backbone that acts as a triple agonist at GIP, GLP-1, and glucagon receptors. Developed by Eli Lilly, it represents a new class of multi-receptor agonist peptides. Phase 2 trial data published in the New England Journal of Medicine demonstrated significant effects on body weight and metabolic markers. Phase 3 trials in 2026 (TRIUMPH-1) are expected to report 80-week obesity data. The C20 fatty diacid moiety at position 17 enables once-weekly dosing in research protocols.