What it is
Retatrutide is a once-weekly injection developed by Eli Lilly that acts on three hormone receptors: GLP-1, GIP and glucagon. The glucagon signal is thought to increase energy use and fat burning in the liver, on top of the appetite effects.
Phase 3 results (2026)
| Trial | Who | Average weight loss |
|---|---|---|
| TRIUMPH-1 | Obesity or overweight, no diabetes | 19.0% to 28.3% at 80 weeks by dose; 30.3% at 104 weeks on the highest dose (extension group) |
| TRIUMPH-2 | Type 2 diabetes with obesity | 12.7% to 20.8% at 80 weeks |
| TRIUMPH-3 | BMI 35+ with heart disease | 21.6% to 22.6% at 80 weeks |
Side effects
Stomach side effects were the most common and rose with dose: nausea in up to about 4 in 10 people on the highest dose, and vomiting in up to a quarter. Around 1 in 9 people on the highest dose stopped because of side effects. Skin-sensation changes (dysesthesia) were also reported.
Approval status
As of October 2026, retatrutide is not approved by any regulator, including the US FDA and Kenya's Pharmacy and Poisons Board. Lilly has said it plans to file with the FDA in early 2027. Products sold as "retatrutide" today are not approved medicines, and their content and quality cannot be guaranteed.
Talk it through with a doctor
Whether any of these medicines is right for you depends on your health, your history and your goals. The first phone consultation is free, and there is no obligation.
Book a free consultation