What is retatrutide?
If you have seen retatrutide mentioned alongside Ozempic and Mounjaro and want a straight explanation of what it actually is, this is the place to start. No jargon, no hype.
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What is retatrutide?
Retatrutide is a peptide, a short chain of amino acids, made in a lab to copy the effect of three natural hormones your body releases around eating. It belongs to the same broad family as semaglutide and tirzepatide, the compounds behind Ozempic, Wegovy, Mounjaro and Zepbound. What makes it distinct is that it acts on three targets at once, which is why it is described as a triple agonist.
Who makes it and why the interest?
Retatrutide is developed by Eli Lilly, the same company behind tirzepatide, and carries the development code LY3437943. The interest comes from its trial results: in studies it has produced some of the largest average weight reductions reported for this class of drug, which is why it is often discussed as a potential next step after the current GLP-1 medicines.
What does retatrutide do?
By switching on the GLP-1, GIP and glucagon receptors together, it lowers appetite, helps steady blood sugar, and increases how much energy the body uses. The combination is designed to do more than drugs that hit only one or two of those targets. For the step-by-step mechanism, see how does retatrutide work.
Mechanistic summary drawn from published literature, provided for research context only. Not a therapeutic claim.
Is retatrutide a GLP-1?
It uses the GLP-1 receptor, but calling it a GLP-1 drug undersells it. Semaglutide is GLP-1 only, tirzepatide adds GIP, and retatrutide adds glucagon on top of both. So it is best described as a triple agonist within the wider GLP-1 family. The GLP-1 family comparison shows where each one sits.
Is retatrutide legal or approved?
Retatrutide is not an approved medicine. As of August 2026 it is still in Phase 3 trials, and it is sold only for research use, which is not tested or approved for human use. The term you will see for this is research peptide. Our guide on what a research peptide is explains the category, and is retatrutide FDA approved covers the regulatory timeline.
References
- Jastreboff AM, Kaplan LM, Frias JP, et al. Triple-Hormone-Receptor Agonist Retatrutide for Obesity - A Phase 2 Trial. N Engl J Med. 2023;389(6):514-526. PMID 37366315.
- Retatrutide (LY3437943) Phase 3 TRIUMPH program. ClinicalTrials.gov. Trial records.
Frequently asked questions
What is retatrutide used for?
It is being studied mainly for obesity, and in trials also in people with type 2 diabetes and heart disease. It is not yet an approved treatment for any of these.
What is retatrutide also known as?
Its development code name is LY3437943. It does not yet have a brand name because it is not approved.
Is retatrutide the same as Ozempic?
No. Ozempic is a brand of semaglutide, a GLP-1 only drug. Retatrutide is a different, investigational triple agonist.
Who makes retatrutide?
It is developed by Eli Lilly and Company.