Compound Guide

Retatrutide
Research Guide

Reference data and research context for retatrutide (LY3437943) — a synthetic peptide studied as a triple GIP / GLP-1 / glucagon receptor agonist.

Research reference · Updated May 2026

Research Overview

Retatrutide, known by the development code LY3437943, is a synthetic peptide studied as a triple incretin receptor agonist. It is engineered to engage three receptors simultaneously — the GIP receptor, the GLP-1 receptor and the glucagon receptor — placing it on the most complex rung of the single / dual / triple agonist ladder described in our GLP Research Overview.

It is supplied as a lyophilized powder for laboratory research and is studied in receptor-binding assays, cell-based signaling models and comparative pharmacology work alongside other incretin agonist peptides.

Mechanism Summary

Retatrutide is studied as an agonist at three G-protein-coupled receptors. Engaging the GIP, GLP-1 and glucagon receptors together produces a combined signaling profile that researchers examine through downstream readouts such as cyclic AMP (cAMP) accumulation in cell-based assays. The research interest in a triple agonist is the opportunity to study how concurrent activation of all three incretin pathways differs from single- or dual-receptor engagement under controlled conditions.

Reference Data

Compound nameRetatrutide
SynonymsLY3437943
CAS number2381089-83-2
Molecular formulaC221H342N46O68 (reported)
Molecular weight≈ 4731.4 g/mol
Peptide classTriple incretin receptor agonist (GIP / GLP-1 / glucagon)
Physical formLyophilized powder
Purity≥ 99% identity — verified by COA on every batch

Molecular values are provided as published reference figures for research identification. Always confirm against the batch-specific Certificate of Analysis.

Research Applications

In laboratory research, retatrutide is commonly studied in:

  • Triple receptor-binding and receptor-activation assays
  • cAMP and downstream signaling readouts in cell-based models
  • Comparative potency profiling against dual and single agonists
  • Structure-activity relationship (SAR) research
  • Peptide stability, formulation and reconstitution studies

Storage Information

Lyophilized retatrutide is the most stable form and should be stored cold and protected from light and moisture until use. Once reconstituted with bacteriostatic water, the working solution becomes considerably more sensitive — keep it refrigerated and use it within a limited window. Full handling protocols are in the Lyophilized Storage Guide, and the Reconstitution Calculator will compute concentration and draw volumes for any vial size.

Research Use Only

Retatrutide is sold strictly for laboratory and in-vitro research. It is not for human consumption, veterinary use, or any diagnostic or therapeutic application. Nothing on this page is medical, dosing, or therapeutic advice.

Frequently Asked Questions

What is retatrutide?

Retatrutide (development code LY3437943) is a synthetic peptide studied as a triple receptor agonist, engaging the GIP, GLP-1 and glucagon receptors. It is supplied for laboratory research use only.

What is the CAS number for retatrutide?

Retatrutide has the CAS registry number 2381089-83-2. It is also referenced by the development code LY3437943.

How is retatrutide different from tirzepatide?

Retatrutide is studied as a triple agonist — GIP, GLP-1 and glucagon receptors — while tirzepatide is a dual agonist engaging only the GIP and GLP-1 receptors. See the Retatrutide vs Tirzepatide comparison for a full side-by-side.

How should retatrutide be stored?

Lyophilized retatrutide is most stable kept cold and protected from light. Once reconstituted, working solutions should be refrigerated and used within a limited window. See the Lyophilized Storage Guide.

Retatrutide in the Catalog

Research-grade retatrutide — 99%+ identity purity, COA on every batch, same-day fulfillment from Sacramento, CA.

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For laboratory and research use only. This guide is research reference material — not medical advice, dosing guidance, or a therapeutic claim. Retatrutide is intended exclusively for in-vitro and laboratory research.