Retatrutide (Investigational Triple Agonist)

Retatrutide is Eli Lilly's investigational triple receptor agonist, simultaneously activating GLP-1, GIP, and glucagon receptors. Glucagon agonism directly elevates metabolic rate and stimulates fat oxidation, complementing appetite suppression and insulin-sensitizing effects of the GLP-1/GIP axis. The Phase 3 TRIUMPH-1 trial (N=2,339, 80 weeks, results announced May 2026) achieved 28.3% average total body weight loss at the 12 mg maximum dose, with 45.3% of participants losing 30% or more body weight. Placebo weight loss was 3.9%. These results approach or match outcomes of Roux-en-Y gastric bypass -- the highest average weight loss ever recorded in a Phase 3 drug study. Dose-dependent results: 17.6% (4 mg), 23.7% (9 mg), 28.3% (12 mg). Discontinuation due to adverse events: 4.1% (4 mg), 6.9% (9 mg), 11.3% (12 mg) vs 4.9% placebo. GI side effects drive discontinuation -- expected with incretin class. Not yet commercially available. Eli Lilly targeted NDA submission for Q4 2026, with projected approval in late 2027 to early 2028 on standard 10-12 month review. Pricing not yet announced. Patients interested should discuss remaining TRIUMPH trial enrollment with their physician.