Overview GLP3-R is the catalog designation for retatrutide (LY3437943), a synthetic peptide characterized in the peer-reviewed literature as a single-molecule agonist at three receptors: GIP, GLP-1, and glucagon.[1] Coskun and colleagues published the discovery-to-proof-of-concept characterization in Cell Metabolism, and Urva et al. reported the first multiple-ascending-dose clinical pharmacology study in The Lancet.[1][2] What distinguishes this compound within the incretin literature is the th

How does GLP3-R work? What is its mechanism of action?

Reported Mechanism 1. Triple Receptor Engagement Retatrutide is described as engaging three class-B G-protein-coupled receptors with a single peptide sequence: the GIP receptor, the GLP-1 receptor, and the glucagon receptor.[1] This distinguishes it from dual GIP/GLP-1 agonism and from GLP-1-selective agonism, and it is the structural feature that defines the compound's research role.[8] 2. Incretin-Axis Signalling GLP-1 and GIP receptor agonism act on the incretin axis, where insulinotropic act

What are the research applications of GLP3-R?

Research Applications Published investigations of retatrutide fall into the following areas. All studies listed used the pharmaceutical formulation. Receptor pharmacology and discovery characterization — Coskun et al. reported the discovery-to-proof-of-concept work defining triple GIP/GLP-1/glucagon agonism.[1] Clinical pharmacology and dose-ranging — Urva et al. published a phase 1b multiple-ascending-dose trial in people with type 2 diabetes.[2] Obesity research — Jastreboff et al. reported a

What does the research summary say about GLP3-R?

Research Summary Foundational Studies StudyTypeSubject of ReportRef Coskun et al. (2022)Discovery / proof of conceptCharacterization of LY3437943 as a triple glucagon, GIP, and GLP-1 receptor agonist[1] Urva et al. (2022)Phase 1b multiple-ascending doseClinical pharmacology in people with type 2 diabetes[2] Jastreboff et al. (2023)Phase 2 (obesity)Triple-hormone-receptor agonist evaluated in adults with obesity[3] Rosenstock et al. (2023)Phase 2 (type 2 diabetes)Placebo- and active-controlled pa

How should GLP3-R be stored?

Store lyophilized at -20°C for long-term storage, or 2-8°C short-term. After reconstitution with bacteriostatic water, store refrigerated (2-8°C) and avoid repeated freeze-thaw cycles.

GLP3-R: Chemical Properties

10 PubMed CitationsExpert ReviewedGMP CertifiedLast Reviewed: July 2026

Chemical Properties

Synonyms	Retatrutide, LY3437943, GLP3-R
Class	Synthetic acylated peptide; triple GIP / GLP-1 / glucagon receptor agonist
Structural Basis	Single peptide sequence engineered from an incretin backbone with a fatty-diacid conjugate supporting albumin binding, as described by Coskun et al. (2022)
Appearance	White-to-off-white lyophilized powder
Regulatory Status	Investigational — not approved by FDA or EMA for any indication
Classification	Research peptide

Identifiers

Development Code	LY3437943
Purity Standard	≥98% by HPLC
Identity Confirmation	Mass spectrometry
Detection Methods	RP-HPLC, LC-MS/MS

Editorial Research Note

“Research Summary Foundational Studies StudyTypeSubject of ReportRef Coskun et al.”

Pure U.S. Peptides Research Standards TeamInternal editorial group summarising published peptide research for an audience of qualified independent investigators.

References

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 Metab. 2022;34(9):1234-1247.e9.
Urva S, Coskun T, Loh MT, et al. LY3437943, a novel triple GIP, GLP-1, and glucagon receptor agonist in people with type 2 diabetes: a phase 1b, multicentre, double-blind, placebo-controlled, randomised, multiple-ascending dose trial. Lancet. 2022;400(10366):1869-1881.
Jastreboff AM, Kaplan LM, Frías JP, et al. Triple-Hormone-Receptor Agonist Retatrutide for Obesity - A Phase 2 Trial. N Engl J Med. 2023;389(6):514-526.
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 conducted in the USA. Lancet. 2023;402(10401):529-544.
Sanyal AJ, Kaplan LM, Frias JP, et al. Triple hormone receptor agonist retatrutide for metabolic dysfunction-associated steatotic liver disease: a randomized phase 2a trial. Nat Med. 2024;30(7):2037-2048.
Urva S, O'Farrell L, Du Y, et al. The novel GIP, GLP-1 and glucagon receptor agonist retatrutide delays gastric emptying. Diabetes Obes Metab. 2023;25(9):2784-2788.
Katsi V, Koutsopoulos G, Fragoulis C, Dimitriadis K, Tsioufis K. Retatrutide - A Game Changer in Obesity Pharmacotherapy. Biomolecules. 2025;15(6):796.
Coskun T, Sloop KW, Loghin C, et al. LY3298176, a novel dual GIP and GLP-1 receptor agonist for the treatment of type 2 diabetes mellitus: From discovery to clinical proof of concept. Mol Metab. 2018;18:3-14.
Hammoud R, Drucker DJ. Beyond the pancreas: contrasting cardiometabolic actions of GIP and GLP1. Nat Rev Endocrinol. 2023;19(4):201-216.
Samms RJ, Coghlan MP, Sloop KW. How May GIP Enhance the Therapeutic Efficacy of GLP-1? Trends Endocrinol Metab. 2020;31(6):410-421.

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GLP3-R: Chemical Properties

Chemical Properties

Identifiers

References

Related Research Questions

Related research

GLP3-R: Chemical Properties

Chemical Properties

Identifiers

References

Related Research Questions

Related research