Overview
- Lilly said Thursday that in its Phase 3 Triumph‑1 trial patients on the highest 12 mg dose lost an average 28.3% of body weight at 80 weeks, about 45% lost 30% or more, and a subset assessed at 104 weeks averaged roughly 30.3% weight loss.
- Retatrutide is a weekly injectable that activates three gut‑hormone receptors — GLP‑1 to suppress appetite, GIP to affect insulin and fat storage, and glucagon to increase energy use — a combination that may explain its larger effects versus one‑ or two‑target drugs.
- The trial recorded common GLP‑1 class side effects such as nausea, diarrhea and constipation, plus higher reports of dysesthesia and urinary tract infections at the top dose and an 11% discontinuation rate for side effects on the highest dose.
- Lilly released the results in a company statement rather than a peer‑reviewed paper and said it expects to file for FDA approval this year with a possible launch in 2027 if regulators clear the drug.
- If approved, retatrutide could offer a non‑surgical option for people with severe obesity and reshape the market for weight‑loss drugs, but real‑world tolerability, long‑term safety, regulatory classification, and pricing will determine uptake and clinical use.