General Questions About Retatrutide
Frequently asked questions about what retatrutide is, who is developing it, and its current status.
What is retatrutide?
Retatrutide (LY3437943) is an investigational medication developed by Eli Lilly and Company. It is a single peptide molecule that simultaneously activates three metabolic hormone receptors: GIP (glucose-dependent insulinotropic polypeptide), GLP-1 (glucagon-like peptide-1), and glucagon receptors. This triple receptor agonism is a novel approach designed to address obesity and type 2 diabetes through complementary metabolic pathways.
Is retatrutide FDA-approved?
No. As of early 2025, retatrutide is an investigational compound in Phase 3 clinical development. It has not been approved by the FDA or any other regulatory authority worldwide. It is not available for prescription or commercial purchase. Any legitimate use is limited to authorized clinical trials.
Who is developing retatrutide?
Retatrutide is being developed by Eli Lilly and Company, a major pharmaceutical company based in Indianapolis, Indiana. Lilly also developed tirzepatide (marketed as Mounjaro for type 2 diabetes and Zepbound for obesity), which is a related dual GIP/GLP-1 receptor agonist.
What does LY3437943 mean?
LY3437943 is retatrutide's development code assigned by Eli Lilly. The 'LY' prefix identifies it as a Lilly compound, and the numerical designation is its internal identifier. 'Retatrutide' is the drug's International Nonproprietary Name (INN), which is the standardized name for scientific and medical communication.
What conditions is retatrutide being studied for?
Retatrutide is primarily being studied for the treatment of obesity and type 2 diabetes in the Phase 3 TRIUMPH clinical program. The Phase 2 data also showed significant liver fat reduction, which has generated interest in its potential for metabolic dysfunction-associated steatotic liver disease (MASLD, formerly NAFLD), though a dedicated liver disease Phase 3 program has not been publicly announced.
How is retatrutide different from semaglutide or tirzepatide?
Semaglutide (Ozempic/Wegovy) targets only the GLP-1 receptor. Tirzepatide (Mounjaro/Zepbound) targets both GIP and GLP-1 receptors. Retatrutide targets all three: GIP, GLP-1, and glucagon receptors. The addition of glucagon receptor agonism is hypothesized to increase energy expenditure and promote liver fat reduction, which are effects not available from single or dual agonists.
Does retatrutide have a brand name?
No. Retatrutide does not have a brand name because it has not received marketing authorization from any regulatory agency. Brand names are typically assigned during the regulatory approval process. The drug is referred to by its INN (retatrutide) or development code (LY3437943) in scientific literature.
When might retatrutide be available?
Specific timelines are uncertain and depend on Phase 3 trial outcomes, regulatory submissions, and agency review times. Based on typical development timelines and assuming positive Phase 3 results, regulatory submissions could potentially occur around 2026-2027, with possible approval in the 2027-2028 timeframe. These are estimates, not commitments from Eli Lilly or regulatory agencies.