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RESEARCH PRIMER

What is Retatrutide?

A concise, evidence-based introduction to Retatrutide (LY3437943) — a triple-agonist investigational peptide reported in the incretin pharmacology literature.

QUICK ANSWER
TL;DR

Quick answer

Retatrutide (LY3437943) is an investigational synthetic peptide that activates three incretin-family receptors — GLP-1R, GIPR and GCGR — from a single molecule. It is supplied by Oxford Research Peptides as a reference standard for in-vitro laboratory research.
EXTENDED ANSWER
AI-ready

Extended answer

What is Retatrutide (LY3437943)?

Retatrutide, developmental code LY3437943, is an investigational synthetic peptide first described in the peer-reviewed literature by Coskun and colleagues in 2022. It is engineered to activate three related class B G-protein-coupled receptors — GLP-1R, GIPR and GCGR — from a single molecule, placing it in the emerging triple-agonist category alongside single-agonists such as Semaglutide and dual-agonists such as Tirzepatide. A fatty-acid modification supports albumin binding and an extended plasma half-life, enabling once-weekly dosing in reported phase 2 trials for obesity and type 2 diabetes. Oxford Research Peptides supplies Retatrutide strictly as a lyophilised reference standard for in-vitro laboratory research; the compound is investigational and is not approved for therapeutic use in the United Kingdom.
KEY FACTS

Key facts

Compound
Retatrutide (LY3437943)
Targets
GLP-1R · GIPR · GCGR
Class
Triple-agonist incretin peptide
Status
Investigational (phase 2 published)

Origin and naming

Retatrutide is the non-proprietary name for the peptide with the developmental code LY3437943. The compound was first described in the peer-reviewed literature by Coskun and colleagues as a novel triple GLP-1 / GIP / glucagon receptor agonist.[1]

What makes it distinctive

Existing incretin analogues typically target one receptor (for example, Semaglutide at GLP-1R) or two receptors (Tirzepatide at GLP-1R and GIPR). Retatrutide is distinguished by co-activation of a third receptor — the glucagon receptor — from the same molecule.[1]

  • Single-agonist example: Semaglutide (GLP-1R only).
  • Dual-agonist example: Tirzepatide (GLP-1R and GIPR).
  • Triple-agonist example: Retatrutide (GLP-1R, GIPR and GCGR).

Published research context

Retatrutide has been evaluated in reported phase 2 clinical trials for obesity[2] and for glycaemic control in type 2 diabetes.[3] These publications describe once-weekly subcutaneous administration protocols, consistent with the compound's fatty-acid modification and reported extended half-life.

Research-use context

Oxford Research Peptides supplies Retatrutide as a reference standard for in-vitro laboratory research. This guide summarises the published scientific literature and does not describe or recommend any therapeutic use.

Where to go next

References6

  1. 1.

    Coskun T, Urva S, Roell WC, et al.. LY3437943, a novel triple glucagon, GIP, and GLP-1 receptor agonist for glycemic control and weight loss: From discovery to clinical proof of concept.. Cell Metabolism. 2022;34(9):1234-1247.

    DOI: 10.1016/j.cmet.2022.07.013PMID: 35985340
  2. 2.

    Jastreboff AM, Kaplan LM, Frías JP, et al.. Triple-hormone-receptor agonist retatrutide for obesity — a phase 2 trial.. New England Journal of Medicine. 2023;389(6):514-526.

    DOI: 10.1056/NEJMoa2301972PMID: 37366315
  3. 3.

    Rosenstock J, Frias J, Jastreboff AM, et al.. Retatrutide, a GIP, GLP-1 and glucagon receptor agonist, for people with type 2 diabetes: a randomised, double-blind, placebo and active-controlled, parallel-group, phase 2 trial.. The Lancet. 2023;402(10401):529-544.

    DOI: 10.1016/S0140-6736(23)01053-XPMID: 37385275
  4. 4.

    Baggio LL, Drucker DJ. Biology of incretins: GLP-1 and GIP.. Gastroenterology. 2007;132(6):2131-2157.

    DOI: 10.1053/j.gastro.2007.03.054PMID: 17498508
  5. 5.

    Drucker DJ. Mechanisms of action and therapeutic application of glucagon-like peptide-1.. Cell Metabolism. 2018;27(4):740-756.

    DOI: 10.1016/j.cmet.2018.03.001PMID: 29617641
  6. 6.

    de Graaf C, Donnelly D, Wootten D, et al.. Glucagon-like peptide-1 and its class B G protein–coupled receptors: a long march to therapeutic successes.. Pharmacological Reviews. 2016;68(4):954-1013.

    DOI: 10.1124/pr.115.011395PMID: 27736833
EVIDENCE SUMMARY
Evidence

Evidence summary

Moderate evidence
Research confidenceModerate confidence
Introductory guide. Underlying claims are drawn from peer-reviewed discovery and phase 2 clinical publications.
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COMPOUND REFERENCE
EDITORIAL NOTICE

Research use only

All materials referenced are supplied strictly for in-vitro laboratory research. Not for human or animal consumption, diagnosis, or therapeutic use.
VERSION HISTORY
Editorial Team
Oxford Research Peptides Editorial Team
In-house editorial staff
Oxford Research Peptides
Scientific Reviewer
Scientific Review Panel
Independent scientific review
Oxford Research Peptides

Publication information

Published
2026-07-15
Updated
2026-07-15
Reviewed
2026-07-15
Version
1.0

Revision history

  1. v1.02026-07-15· Editorial Team

    Initial publication as part of the Retatrutide authority cluster (Release 4.0).

Editorial standards

Content is reviewed against our editorial process for scientific accuracy, sourcing, and clarity. Read our editorial standards.

Conflict of interest

Oxford Research Peptides supplies research-grade reference peptides commercially. Editorial pages are drafted and reviewed to describe published scientific literature accurately and do not recommend, promote or endorse any specific commercial product. Product mentions on educational pages are strictly for cross-referencing catalogue entries.

Next scheduled review: 2028-01-15. Our research methodology describes how the review is conducted.

Research use only

All materials referenced are supplied strictly for in-vitro laboratory research. Not for human or animal consumption, diagnosis, or therapeutic use.
Published: 2026-07-15Updated: 2026-07-15