Retatrutide, a new triple-hormone obesity drug developed by Eli Lilly, has demonstrated record-breaking efficacy in late-stage clinical trials, with patients on the highest dose losing an average of 25 per cent of their body weight after 80 weeks and 30 per cent by 104 weeks. The drug also significantly improved other obesity-related conditions, reducing knee pain by up to 62 per cent in those with osteoarthritis, decreasing sleep apnea events by up to 57 per cent, and improving blood pressure and cholesterol levels across all participants. The results, published in the New England Journal of Medicine, represent a substantial advance beyond existing obesity medications.

The trial included 2,339 participants from 131 sites across 11 countries, with participants randomly assigned to receive 4 mg, 9 mg, 12 mg of retatrutide or placebo starting in 2023. Participants had an average starting weight of 113 kilograms and a body mass index of 40; over a third had prediabetes, which resolved in more than 90 per cent of these cases by trial's end. Retatrutide works by simulating three hormones—GLP-1, GIP, and glucagon—representing an advancement over Eli Lilly's existing dual-hormone tirzepatide and Novo Nordisk's semaglutide, which target fewer hormonal pathways.