Retatrutide delivers unprecedented weight loss in obesity Phase 3 trial

Eli Lilly's retatrutide, a weekly triple hormone receptor agonist (GLP-1, GIP, glucagon), produced an average 28.3% weight loss (70.3 lb) over 80 weeks at the 12 mg dose in a Phase 3 trial of 2,339 adults with obesity or overweight and a weight-related comorbidity. The 12 mg group lost more weight than the 9 mg and 4 mg groups, with 65.3% reaching a BMI below 30 and 37.5% starting with BMI ≥40; 45.3% achieved at least 30% weight loss. Retatrutide’s weight loss appears to exceed current drugs Wegovy and Zepbound. The drug, which combines GLP-1 and GIP with glucagon, also improved cardio-metabolic risk factors, though side effects such as nausea, diarrhea, constipation, and vomiting increased with dose.