Retatrutide (LY3437943) is an investigational triple GLP-1/GIP/glucagon receptor agonist developed by Eli Lilly — designed to target all three of these metabolic hormone receptors at once. It is informally called "GLP-3" because it adds a third receptor to the dual-agonist approach of tirzepatide. Retatrutide is investigational and not FDA-approved.
The triple mechanism, as described in the research literature, works on three fronts. The GLP-1 component reduces appetite and slows gastric emptying. The GIP component influences insulin secretion and fat metabolism. The glucagon component — the distinguishing addition — is associated with increased energy expenditure and hepatic fat oxidation in trials.
In the Phase 2 clinical trial published in the New England Journal of Medicine (2023), participants receiving the highest dose of retatrutide reported an average body-weight reduction of about 24% at 48 weeks. These figures describe what researchers observed in that trial — not results GLP3 Weight Loss offers, promises, or provides.
Important: Retatrutide remains in clinical trials and is not approved by the U.S. FDA. It is not available as an approved prescription medication. GLP3 Weight Loss is an educational resource and does not provide, prescribe, dispense, or arrange access to retatrutide. For FDA-approved options, read about semaglutide and tirzepatide, and speak with an independent licensed provider.