GLP-1 Family: Retatrutide vs Semaglutide vs Tirzepatide

The GLP-1 family is the most talked-about area in metabolic research. Three names dominate the conversation — semaglutide, tirzepatide and retatrutide — and the simplest way to understand them is by how many receptors each one acts on.

This guide explains the receptors involved, compares the three compounds, and is clear about which are approved medicines and which is still in trials.

The receptors involved

Three gut/metabolic receptors come up: GLP-1 and GIP are incretin pathways associated with reduced appetite and slower stomach emptying; glucagon is associated with energy expenditure. The more of these a molecule engages, the broader its referenced metabolic effect.

The three compounds

Semaglutide is a single agonist — it acts on GLP-1 alone (the Ozempic/Wegovy molecule). Tirzepatide is a dual agonist — GLP-1 + GIP (the Mounjaro molecule). Retatrutide is a triple agonist — GLP-1 + GIP + glucagon — which is why it is referred to as a "next-generation" candidate and associated with the largest weight changes in its trials.

What the research shows

Retatrutide's phase-2 trials reported substantial weight reduction, and phase-3 trials are ongoing. Because it is the newest and least-studied of the three, the evidence base is the thinnest even as the early signal is the largest. Treat trial figures as research context, not outcomes you should expect.

Where to go next

See the retatrutide product page for its profile and reference protocol, and the calculator for reconstitution maths. As always, confirm material quality on the CoA before anything else.