Retatrutide

Retatrutide (LY3437943) - GLP-1 / GIP / Glucagon Triple Agonist

Retatrutide is a synthetic research peptide developed by Eli Lilly that activates three different metabolic hormone receptors at once: GLP-1 (the same system targeted by semaglutide, the active ingredient in Ozempic and Wegovy), GIP (a gut hormone that regulates insulin, also hit by tirzepatide / Mounjaro), and glucagon (the hormone that tells the body to release stored energy). Most compounds in this class hit one or two of these receptors - retatrutide is the first peptide to hit all three in a single molecule, which is why it is sometimes nicknamed “GLP-3” and is one of the most actively studied peptides in obesity and metabolic research.

Why Triple Agonism Matters

GLP-1 and GIP work mostly on the “intake” side of the energy equation - they reduce appetite, slow digestion, and improve how the body handles sugar. The glucagon receptor adds something different: it works on the “output” side, telling the body to burn stored fat and raise its baseline energy expenditure. By combining both sides in one molecule, researchers can study intake and expenditure together rather than in isolation.

Retatrutide vs Tirzepatide vs Semaglutide

All three peptides come from the same research lineage, but they don’t hit the same receptors. A quick comparison of how they differ at the receptor level:

The practical research difference: tirzepatide added GIP to what semaglutide already did, and retatrutide added glucagon on top of that. Phase 2 trial data published in the New England Journal of Medicine (Jastreboff et al., 2023) reported average weight reductions of about 24% at the highest retatrutide dose over 48 weeks, which is higher than what has been reported in equivalent-length trials of semaglutide or tirzepatide - though direct head-to-head studies are still ongoing.

Research Applications

Retatrutide is used in studies examining:

• Body composition changes under sustained caloric restriction
• How triple-agonist protocols compare to single or dual agonists like semaglutide and tirzepatide
• Blood sugar and insulin response in metabolic models
• Fat accumulation in the liver and its reversal (MASLD / NAFLD research)
• Dose-response curves during gradual dose escalation
• Cardiovascular and metabolic markers under extended exposure

Specifications

Storage & Handling

Unopened vials are kept at 2-8°C under standard cold-chain conditions and remain stable for 12+ months. Reconstitution parameters, solvent compatibility, and post-reconstitution stability for Retatrutide are documented in the published peer-reviewed literature and standard peptide-chemistry references.

Reference Literature

Published clinical and preclinical Retatrutide literature is available through PubMed, Google Scholar, and other peer-reviewed databases. WWP does not provide protocol design, dosing guidance, or administration parameters. Those decisions rest with the researcher and any applicable institutional review board.

Common Questions About Retatrutide Research

Is retatrutide the same as Ozempic?

No. Ozempic is a brand name for semaglutide, which activates one receptor (GLP-1). Retatrutide activates three receptors (GLP-1, GIP, and glucagon) in a single molecule. They come from different manufacturers - semaglutide from Eli Lilly - and behave differently in metabolic research.

What is the difference between retatrutide and tirzepatide?

Tirzepatide (the active ingredient in Mounjaro and Zepbound) activates GLP-1 and GIP. Retatrutide activates those same two receptors plus glucagon. The added glucagon signaling is the key mechanistic difference and is what researchers point to when explaining retatrutide’s stronger effect on body fat and liver fat markers in published trials.

Why is retatrutide sometimes called GLP-3?

“GLP-3” is an informal nickname used in the research community because retatrutide is the third-generation development in the GLP-1 / GLP-1+GIP / GLP-1+GIP+glucagon progression. It is not an official receptor name or a separate molecule - the technical label is “triple agonist” and the compound’s development code is LY3437943.

Is retatrutide FDA approved?

No. As of the most recent public data, retatrutide is still in Phase 3 clinical trials. It is not approved by the FDA for any use. Every vial WWP ships is labeled and sold strictly for laboratory and research use only, not for human consumption.

How is retatrutide stored?

Unopened vials are stored at 2-8°C (refrigerator temperature) and stay stable for 12+ months. Once reconstituted with bacteriostatic water, the solution is kept at 2-8°C and used within 28-30 days.

Purity Guarantee

Every batch is ≥99% purity. Send us a COA from any independent test and we’ll issue store credit regardless of what it shows.