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Research Library / Metabolic research
Understand the three receptor targets, the foundational studies, and what their findings do and do not establish.
Updated October 8, 2026 · Primary studies and regulatory sources linked below
A simplified research map, not a treatment promise.
Retatrutide, also called LY3437943, is an investigational peptide developed by Lilly. It activates GLP-1, GIP and glucagon receptors. “GLP-3” is an informal nickname, not the name of a fourth or separate receptor. Lilly explains the terminology and development status.
RTZ-GLP3 is the name used in SRP’s catalog. This guide discusses the published literature on retatrutide. Citing a clinical trial does not establish that an SRP research vial is the material used in that trial, or verify a particular batch’s identity, purity or performance.
The discovery study characterized one molecule with activity at three receptors. The diagram below names those targets without treating them as independent, guaranteed outcomes.
Glucagon-like peptide-1 receptor, abbreviated GLP-1R. One of the incretin-related targets in the compound’s pharmacology.
Glucose-dependent insulinotropic polypeptide receptor, abbreviated GIPR. A second incretin-related target evaluated alongside GLP-1R.
Abbreviated GCGR. The discovery work explored its contribution to energy expenditure in obese mouse models.
Source: Coskun et al., Cell Metabolism, 2022. Laboratory receptor activity and animal findings cannot, by themselves, predict a person’s outcome.
Coskun and colleagues reported receptor activity, animal experiments and initial clinical observations. A separate phase 1b study by Urva and colleagues evaluated safety, drug exposure and metabolic measures over 12 weeks in people with type 2 diabetes. Gastrointestinal disorders were the most frequently reported treatment-emergent adverse events. These early studies supported further investigation.
The 338-participant, placebo-controlled study followed adults for 48 weeks and measured changes in body weight. It also assessed safety. Gastrointestinal events and dose-related increases in heart rate were reported. Results belong to the study’s selected participants, protocol and investigational material, not to a retail supplier’s vial.
Lilly reports an ongoing phase 3 development program and published clinical results. Continued development does not equal regulatory approval. Check the sponsor’s current updates and the underlying trial publications when evaluating newer claims.
Use the library to compare research topics, and review the current listing separately for available vial contents and linked documentation.
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