Retatrutide

Overview

Retatrutide is an investigational triple agonist that activates GIP, GLP-1, and glucagon receptors. It is being developed by Eli Lilly for weight loss. It is not yet FDA-approved and is not available outside clinical trials as of early 2026. Phase 2 data have been promising—with some participants losing up to about 24% of body weight—but the drug is still in Phase 3. People interested in the latest weight-loss medications often ask about retatrutide; for now, access is only through participation in a trial. Once approved, it may become another option alongside semaglutide and tirzepatide.

How It Works (Mechanism of Action)

Retatrutide combines GIP and GLP-1 agonism (like tirzepatide) with glucagon receptor agonism. Glucagon can increase energy expenditure and fat utilization. The triple mechanism may explain the substantial weight loss seen in early trials. Full characterization will come with Phase 3 and approval.

Primary Uses

Weight loss (investigational). No approved uses yet. Not available outside clinical trials.

FDA & Regulatory Status

Not yet FDA-approved. In Phase 3 clinical trials (Eli Lilly). Not available outside clinical trials as of early 2026. Do not purchase “retatrutide” from non-trial sources—it is not legally marketed.

Last reviewed February 2026.