Retatrutide helped more than half of patients with type 2 diabetes and obesity exit the obesity category after 80 weeks of taking the highest dose. The TRIUMPH-2 study also demonstrated that up to 40% of participants achieved normal blood glucose levels.
The results were presented at the European Association for the Study of Diabetes congress in Milan and published in The Lancet. However, the treatment has not yet received approval in any country, and side effects increased with increasing dosage.
Taken once a week, retatrutide acts on three mechanisms related to weight and glucose control. Similar to drugs such as Ozempic and Mounjaro, it enhances feelings of satiety. The difference is that it also affects glucagon—a hormone that helps the body expend energy.
TRIUMPH-2 Study Details
The TRIUMPH-2 study involved 1152 adults with type 2 diabetes and obesity. Weight loss was observed at all assessed doses, with results improving as the amount of the drug increased.
Among participants with the most severe degree of obesity, the average reduction was 23.4%, or 27.5 kg, when using the 12 mg dose. By the end of 80 weeks, 59.5% of patients receiving this dose were below the index used to determine obesity.
Improvement was also noted in glucose control. Glycated hemoglobin, an analysis showing the average blood sugar level over the last three months, decreased by approximately 1.5 percentage points at all doses. At the highest doses, nearly 80% of participants were below the level used for diabetes diagnosis, and about 40% reached the range considered normal.
Researchers also evaluated other indicators related to cardiovascular health. At the 12 mg dose, improvements were observed in markers related to blood fat, inflammation, blood pressure, and waist circumference.
Key Findings and Side Effects
The main results showed that this data does not allow one to claim that retatrutide prevents heart attacks, strokes, or kidney failure; special studies tracking these issues are required for such a conclusion.
The method of calculating weight loss also affects the final result. If participants who completely stopped treatment are included, the average reduction at the 12 mg dose was 18.8%. In this analysis, 47% lost at least 20% of their weight.
The most common problems were diarrhea, nausea, and vomiting. These occurred more frequently among participants receiving the highest doses.
At the 12 mg dose, the rates were as follows: in the placebo group, they were 13.2%, 8%, and 4.2% respectively.
Another noted effect was dysesthesia—a change in sensitivity that can cause tingling, burning, or discomfort on the skin. This symptom also became more frequent with increasing dosage: it reached 4.5% among patients on 4 mg, 5.6% on 9 mg, and 7.3% on 12 mg. In the placebo group, this rate was 0.7%.
Cases of low blood pressure and urinary tract infections were also registered, in addition to discontinuation due to adverse events. The cause of the change in sensitivity is still unknown.
Future Plans
Eli Lilly plans to submit an application for retatrutide approval in the United States in the first quarter of 2027. Until then, the substance can only be legally obtained by clinical trial participants. Syringes sold outside of these studies do not guarantee compliance with the composition, efficacy, or safety results of the study.