GLP-3 isn
Is GLP-3 a real hormone or receptor? No. There is no GLP-3 hormone or GLP-3 receptor in human biology. 'GLP-3' is marketing shorthand for retatrutide, not a scientific classification used by the FDA, NEJM, or drug manufacturers.
How is retatrutide different from GLP-1 drugs like semaglutide? Semaglutide is a GLP-1 receptor agonist — it mimics one hormone. Retatrutide is a triple agonist that activates GLP-1, GIP, and glucagon receptors. The additional glucagon receptor activity is thought to increase energy expenditure, which may explain the larger weight-loss numbers seen in trials.
Is retatrutide FDA-approved? Not as of September 2026. Retatrutide is investigational. Eli Lilly has indicated it plans to file for FDA approval for obesity in early 2027 after initially targeting late 2026.
How much weight loss has retatrutide shown in clinical trials? Phase 2 data published in the New England Journal of Medicine showed up to 24.2% weight loss at 48 weeks. Phase 3 TRIUMPH-1 data reported up to 28.3% at 80 weeks and 30.3% at 104 weeks on the 12 mg dose.
Are retatrutide side effects worse than GLP-1 drugs? Trial data so far suggests a higher rate of gastrointestinal side effects with retatrutide than with placebo, including nausea, diarrhea, vomiting, and constipation. The pattern fits the class of incretin-based drugs, but adding a third active receptor appears to intensify GI effects somewhat.