Retatrutide vs Mounjaro: How They Compare

Mounjaro is the brand name for tirzepatide when it is prescribed for type 2 diabetes. Retatrutide is a separate, investigational molecule: a triple agonist that is not yet approved by the FDA. Both come from Eli Lilly, and both are once-weekly injections, which is why they often get compared. Here's what is publicly known about each.

Important: Retatrutide is not FDA-approved and cannot be prescribed. Mounjaro is approved. The information below is educational and not medical advice.

Is Mounjaro the same as retatrutide?

No. Mounjaro is tirzepatide, a dual agonist that activates the GLP-1 and GIP receptors, approved for type 2 diabetes. Retatrutide is a different drug, a triple agonist that also activates the glucagon receptor, and it is still in clinical trials. They are not interchangeable, and only Mounjaro (tirzepatide) can currently be prescribed.

Side-by-side comparison

Retatrutide: still investigational

Retatrutide is a triple agonist in Eli Lilly's pipeline. In its Phase 2 obesity trial, the 12 mg weekly dose achieved about 24.2% mean weight loss at 48 weeks, and the drug is now progressing through the Phase 3 TRIUMPH program. It has a roughly 6-day half-life and is dosed once weekly in trials. But it remains investigational: it is not approved, not sold as Mounjaro or any other brand, and not available by prescription.

Mounjaro: approved tirzepatide

Mounjaro is tirzepatide approved for improving blood sugar control in adults with type 2 diabetes, alongside diet and exercise. (The same molecule is marketed as Zepbound for chronic weight management.) It is a once-weekly subcutaneous injection, started low and escalated gradually under a provider's direction, with established FDA labeling covering dosing and safety.

Does retatrutide cause more weight loss than Mounjaro?

Retatrutide's Phase 2 weight-loss figures were numerically higher than tirzepatide's typical obesity-trial figures, but this is not a head-to-head comparison, and retatrutide has not completed Phase 3. Mounjaro is approved specifically for diabetes; weight loss is a separate indication (Zepbound). Comparing an investigational drug's early numbers to an approved drug's established results can be misleading, and only a healthcare provider can advise on approved treatment.

Can my doctor prescribe retatrutide?

No. Because retatrutide is not FDA-approved, it cannot be prescribed as an approved medicine. Mounjaro and other approved GLP-1 medicines can be. Anything sold as "retatrutide" outside a formal clinical trial is not an approved medicine and may carry safety and quality risks. Talk to your provider about approved options or clinical-trial eligibility.

Medical Disclaimer

This page is general educational information, not medical advice. Retatrutide is investigational and not FDA-approved. Trial figures are reported as published in the referenced studies and are not dosing recommendations. RetaPal is a private tracking and reminder app only. It does not recommend, calculate, or suggest doses. Always follow the dose and schedule given by your own prescriber, and consult your healthcare provider before starting, stopping, or changing any medication.

When you and your provider have agreed on a regimen, RetaPal can quietly log each weekly dose and count down to your next injection, private, offline, and never suggesting a dose.