Evidence review · Published July 22, 2026 · Sources checked July 22, 2026

Retatrutide (GLP-3) research overview

Retatrutide, also identified in the literature as LY3437943, is a single modified peptide studied as an agonist at the GLP-1, GIP, and glucagon receptors. This page separates receptor and animal research from human trial observations and from batch-specific product documentation.

Evidence boundary: research findings do not establish that a separately supplied research product is safe or effective for treating, preventing, or diagnosing any condition. The Pep Labs product is supplied only for qualified in vitro laboratory research and is not for human or animal use.

What is retatrutide (LY3437943)?

The discovery program described LY3437943 as a triple-receptor agonist with activity at the glucagon receptor (GCGR), glucose-dependent insulinotropic polypeptide receptor (GIPR), and glucagon-like peptide-1 receptor (GLP-1R). The shorthand “GLP-3” is a catalog label; it does not mean there is a receptor officially named GLP-3.

Why is retatrutide called a triple agonist?

In receptor assays reported in 2022, LY3437943 activated all three target receptors. Mouse experiments in the same report investigated how combined receptor activity related to food intake, energy expenditure, body weight, and glycemic measures. Those findings characterize the study material, not a separately supplied research batch.

What did the cited human studies examine?

A 12-week phase 1b trial in adults with type 2 diabetes measured safety, pharmacokinetics, and pharmacodynamic outcomes. A later 48-week phase 2 trial in adults with obesity compared multiple retatrutide groups with placebo. The results apply to the characterized investigational product and controlled protocols used in those studies.

Primary sources

  1. Coskun et al., Cell Metabolism (2022), DOI 10.1016/j.cmet.2022.07.013 — receptor assays, preclinical models, and early proof-of-concept work.
  2. Urva et al., The Lancet (2022), DOI 10.1016/S0140-6736(22)02033-5 — a 12-week phase 1b randomized trial.
  3. Jastreboff et al., New England Journal of Medicine (2023), DOI 10.1056/NEJMoa2301972 — a 48-week randomized phase 2 trial.

Literature and product documentation are different

A publication describes a study. A batch-specific Certificate of Analysis documents characteristics of a supplied research material. One does not substitute for the other.

Review Retatrutide (GLP-3) product specifications · Browse the COA library · Read the research-use policy

Prepared by The Pep Labs Research Editorial Team. This evidence summary is not medical advice and contains no dosing or administration guidance.