Retatrutide vs Tirzepatide

What is the difference between retatrutide and tirzepatide?

One of these is a medicine, and the other is not one yet. Tirzepatide has been an approved drug product since 2022 and is prescribed under a label a regulator reviewed. Retatrutide is investigational: its Phase 3 program has reported, but it is not FDA-approved, no approval elsewhere is listed in this page's sources, and in the US it cannot be lawfully sold to you as a medicine. Retatrutide engages three receptors to tirzepatide's two, and its published trial magnitudes are the largest in the class — but those numbers come from separate trials, so they are an indication of promise, not a league table.

Head-to-head evidence

This page cites no head-to-head trial of retatrutide against tirzepatide. Every 'retatrutide wins by X points' figure you will read is two different trials placed side by side — different participants, different durations, different baseline weights, different endpoints. Cross-trial comparisons in this class have been wrong before, and consistently in the direction of the newer drug.

A common mistake

Reading a trial average as a personal forecast. A 24% mean reduction is the centre of a wide distribution that includes participants who lost very little, under trial conditions that included structured support most people never get.

Educational use only, never medical advice. No doses.