Retatrutide

A triple receptor agonist peptide (GLP-1 receptor + GIP receptor + glucagon receptor) in Phase 3 clinical development by Eli Lilly (internal code LY3437943). Phase 2 SURMOUNT-J trials reported average weight loss of 24.2% over 48 weeks — the highest published for any pharmacotherapy to date. The addition of glucagon receptor agonism to dual GLP-1/GIP activation further enhances energy expenditure through hepatic effects and thermogenesis, potentially producing greater fat mass reduction than tirzepatide.