Retatrutide: The ~28% Drug That Isn’t Here Yet

No. As of mid-2026 retatrutide is investigational — it is not FDA-approved and cannot be legally prescribed or sold for weight loss. Eli Lilly has completed Phase 3 trials and is expected to file for FDA approval around the end of 2026, with a possible decision in 2027. Timelines are not guaranteed.

In Phase 3 TRIUMPH trials, retatrutide produced about 28% average weight loss (TRIUMPH-4 reported 28.7% at 68 weeks; TRIUMPH-1 reported 28.3% at 80 weeks) — the highest of any GLP-1-class drug reported to date, ahead of tirzepatide (Zepbound). These are trial averages in supervised studies, not a promise of individual results.

No — not legally. Because it is not FDA-approved, no licensed US pharmacy or telehealth provider can dispense it for weight loss. Websites selling “retatrutide” as a research chemical or peptide are unapproved, unregulated, and potentially unsafe — the product, purity, and dose are not verified, and using them carries real health and legal risk. Wait for approval or use an FDA-approved option.

Most GLP-1 drugs act on one receptor (semaglutide) or two (tirzepatide: GLP-1 + GIP). Retatrutide acts on three — GLP-1, GIP, and glucagon — which may explain the larger weight loss in trials. It’s sometimes called a “GLP-3” colloquially, though that isn’t an official term.

The approved options today include injectable tirzepatide (Zepbound, the strongest approved weight-loss drug), semaglutide (Wegovy injection or the new Wegovy pill), and oral orforglipron (Foundayo). These have real-world track records and can be prescribed now. Compare them in our GLP-1 medications guide.