Our cast name for a research class more formally called a "triple hormone receptor agonist" — a peptide engineered to activate three separate metabolic receptors (GLP-1, GIP, and glucagon) at once, instead of just one or two.
"GLP-3" is Peptide Curious's cast name for a class of research peptides that the scientific literature calls triple hormone receptor agonists — synthetic peptides engineered to activate three different metabolic receptors in one molecule: GLP-1, GIP, and glucagon. It isn't a standardized chemical name; we use it the same way we use "the Repair Crew" for BPC-157, as a friendlier handle for a real, actively studied research category.
The most advanced compound in this class is retatrutide, an investigational peptide currently in Phase 3 clinical development. Where this page describes published trial results, they refer specifically to retatrutide — the named compound the data comes from — not to "GLP-3" as a distinct substance.
Most earlier metabolic peptides act on a single receptor (GLP-1) or two (GLP-1 and GIP). Triple agonists add a third target — the glucagon receptor — which increases energy expenditure in a way GLP-1-only compounds don't, alongside the appetite and blood-sugar effects GLP-1 and GIP are already known for.
The molecule is designed to bind and activate the GLP-1, GIP, and glucagon receptors together rather than separately, which researchers are studying as a way to combine each receptor's individual effects.
GLP-1 and GIP receptor activity are studied for effects on appetite and insulin secretion — the same pathways behind earlier single- and dual-agonist research.
The added glucagon receptor activity is what researchers highlight as distinct from single- or dual-agonist compounds — it's studied for increasing energy expenditure, not just reducing intake.
Published Phase 2 trial results for retatrutide, the lead compound in this class, include:
As of this research class's most recent published data, retatrutide is in Phase 3 development; results for other compounds in the triple-agonist class are earlier-stage.
Peptide Curious provides educational and editorial content only. It is not medical advice and is not a substitute for a qualified healthcare professional. GLP-3 is discussed here as a research-class nickname for investigational compounds; content may describe emerging research not approved for clinical use.