Retatrutide targets three hormone receptors involved in appetite and metabolism. In the 80-week TRIUMPH-1 trial, average body weight fell by 17.6% to 25.0% across the retatrutide groups, compared with 3.9% with placebo. These are group averages.
Who took part
The trial enrolled adults with obesity, or overweight with a related health condition, without type 2 diabetes. Researchers assigned participants to an investigational treatment or placebo.
What participants experienced
Nausea, diarrhoea and vomiting were among the digestive side effects. Digestive side effects led to discontinuation in 2.2% to 4.6% across the retatrutide groups and 1.2% with placebo.
Evidence reviewed 15 November 2026.