The short answer
Investigational retatrutide reduced average weight more than placebo in TRIUMPH-2, which enrolled adults with overweight or obesity and type 2 diabetes.
The result
The trial randomly assigned 1,152 adults to weekly retatrutide or placebo. At 80 weeks, average weight change was −11.9% with 4 mg, −16.8% with 9 mg, −18.8% with 12 mg, and −5.1% with placebo. The analysis included all randomized participants, with missing measurements handled statistically.
Percent of starting weight
Original chart based on the study. Values are reported group averages.
| Group or measure | Average result |
|---|---|
| Retatrutide 4 mg | −11.9% |
| Retatrutide 9 mg | −16.8% |
| Retatrutide 12 mg | −18.8% |
| Placebo | −5.1% |
The trade-offs
Digestive adverse events were more common with retatrutide, as were low blood pressure and altered skin sensations. Permanent discontinuation because of adverse events or death occurred in approximately 4%, 12%, and 8% of the retatrutide groups, versus 5% with placebo. Investigators considered the reported deaths unrelated to treatment.
These are trial findings, not an approval announcement. Retatrutide remains investigational as of October 31, 2026; this was not a comparison against tirzepatide or semaglutide.
Sources
Bellido and colleagues, TRIUMPH-2, The Lancet, 2026. Funded by Eli Lilly. Study abstract · Development status.