Retatrutide

Mechanism

Retatrutide is a synthetic peptide that activates three distinct hormone receptors at once: GLP-1 (glucagon-like peptide-1), GIP (glucose-dependent insulinotropic polypeptide), and glucagon. The combination is what makes it different from tirzepatide (dual GLP-1 / GIP) and semaglutide (GLP-1 only).

The third agonism — glucagon — is the source of both the larger weight-loss effect observed in trials and the metabolic side-effect profile that's still being characterized in Phase 3.

Research dosing

Phase 2 studies escalated from 1 mg weekly through 12 mg weekly over 24 weeks. The dose-response curve in published data is roughly linear through 8 mg, with diminishing returns above. Half-life of approximately six days supports weekly dosing.

What we cover

Vendor audits for retatrutide focus on COA-verified purity and identity, since the molecule is novel enough that some grey-market vendors have shipped under-purity or misidentified material in early 2026. Cross-lab agreement on retatrutide samples is the single highest-weighted factor in our scoring for this compound.

• weight loss
• metabolic dysfunction
• fatty liver