Experimental drug pairs substantial weight loss with better blood sugar control

An experimental weekly injection helped adults with type 2 diabetes and overweight or obesity lose substantial weight while improving blood sugar control. In an 80-week trial, 31% of participants receiving the highest dose of retatrutide lost at least a quarter of their starting weight, compared with 3% receiving a placebo.

The study randomly assigned 1,152 adults to one of three doses or a placebo. All received dietary counselling and guidance on physical activity. Funded by the drug’s developer, Eli Lilly, the findings were published in The Lancet and presented at a diabetes conference in Milan.

Retatrutide mimics three hormones involved in controlling appetite, blood sugar and energy use. Alongside weight loss and better blood sugar control, researchers reported improvements in blood pressure and cholesterol, and a reduction in a blood marker of inflammation. These findings suggest potential benefits beyond weight loss, though further research must establish whether they translate into fewer health complications.

Side effects remain an important consideration. Digestive problems, including diarrhoea and nausea, were common. About 8% of participants on the highest dose stopped treatment because of adverse events, compared with about 5% receiving the placebo.

Retatrutide has not received regulatory approval. Lilly plans to apply for US approval in the first three months of 2027.