Compounds / Retatrutide

Retatrutide

Also known as: LY3437943

Phase 3 clinical (investigational) Not approved · investigational Category: GLP-1 and Metabolic

The compounds described in this library are research-use-labeled chemicals and are not FDA-approved for human use. This content is factual scientific reference drawn from published literature. It is not medical, dosing, or purchasing advice. VialReport does not sell, supply, or distribute any compound.

Short summary

An investigational triple hormone receptor agonist developed by Eli Lilly, activating the GIP, GLP-1, and glucagon receptors. It is in Phase 3 trials and is not approved by the FDA. Lilly states that it is legally available only to participants in its clinical trials.

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Origin and Development

Developed by Eli Lilly and designated LY3437943. It is described as first-in-class: a single molecule engineered to activate three receptors, adding glucagon receptor agonism to the dual GIP/GLP-1 mechanism of tirzepatide.

Mechanism as Understood in the Literature

Agonist at the receptors for glucose-dependent insulinotropic polypeptide (GIP), glucagon-like peptide-1 (GLP-1), and glucagon. The addition of glucagon receptor activity is the distinguishing feature relative to earlier incretin agents.

Research Status

Advanced clinical development. Phase 2 results reported substantial weight reduction, and the Phase 3 TRIUMPH program has since reported positive topline results across several trials, including TRIUMPH-4 in obesity with knee osteoarthritis, TRIUMPH-1 in obesity, and TRANSCEND-T2D-1 in type 2 diabetes. Additional Phase 3 readouts were expected through 2026. Trials are also under way in obstructive sleep apnoea, chronic low back pain, cardiovascular and renal outcomes, and metabolic dysfunction-associated steatotic liver disease.

Regulatory status · investigational

Not approved by the FDA or any other regulator.

Retatrutide is an investigational molecule with no approved product, no compounding pathway, and no USP/NF monograph.

Any material offered for sale outside a clinical trial is outside the sponsor's supply chain entirely.

Commonly Confused With

Frequently confused with tirzepatide, which shares two of the three receptor targets and is approved, and with semaglutide. The distinguishing feature of retatrutide is glucagon receptor agonism.

How This Compound Is Marketed

Vendors in this market commonly market this compound for weight loss, often citing the trial results reported by the sponsor. These are vendors’ marketing claims, not VialReport’s. VialReport does not verify, evaluate, or endorse them, and nothing on this page is medical, dosing, or purchasing advice or a recommendation to use any compound. See “Research status” above for what the published literature actually establishes.

Vendor listings often cite the trial results reported by the sponsor.

Analytical Profile

A synthetic peptide with fatty-acid modification, in the same general structural family as tirzepatide but a distinct molecule. Because there is no approved reference product available outside the trial supply chain, identity confirmation depends on a certified reference standard, and mass spectrometry is the appropriate method given the close structural similarity to other incretin agonists.

Stability and Handling

No approved product exists, so there is no manufacturer-defined storage specification available outside the clinical trial setting.

Key Literature

  1. 01 Jastreboff AM, et al. Triple-hormone-receptor agonist retatrutide for obesity — a Phase 2 trial. N Engl J Med. 2023;389:514-526.
  2. 02 Eli Lilly and Company. TRIUMPH-4 topline results. December 11, 2025.
  3. 03 Eli Lilly and Company. TRIUMPH-1 topline results. May 21, 2026.
  4. 04 Eli Lilly and Company. TRANSCEND-T2D-1 topline results. March 19, 2026.
  5. 05 ClinicalTrials.gov NCT05929066 (TRIUMPH-1).

VialReport publishes factual reference information and independent test data. Nothing here is medical, dosing, or purchasing advice.

Published reports

Reports for Retatrutide

No reports for this compound yet.

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