GLP-3 RT (Retatrutide): The Complete Research Guide

What is GLP-3 RT (Retatrutide)?

GLP-3 RT is Peptora's research designation for Retatrutide, an investigational single-molecule peptide that simultaneously engages three metabolic receptors: the glucagon-like peptide-1 (GLP-1) receptor, the glucose-dependent insulinotropic polypeptide (GIP) receptor, and the glucagon receptor. Because it activates all three pathways at once, Retatrutide is commonly described in the literature as a triple-receptor agonist or "triple-G" agonist.

The "GLP-3" naming reflects a lineage that researchers find intuitive: single agonists act on one incretin receptor, dual agonists on two, and Retatrutide on three. Throughout this guide the compound is referred to by its canonical research name, GLP-3 RT, with Retatrutide noted as the underlying compound. It is intended exclusively for laboratory research and is not a medicine.

How GLP-3 RT works: the triple-receptor mechanism

The three receptors GLP-3 RT engages sit at the center of how the body senses and manages energy. Studying them together is what makes the compound distinct from earlier incretin research tools:

• GLP-1 receptor — associated in research with insulin secretion, gastric emptying, and satiety signaling.
• GIP receptor — the other major incretin receptor, studied for its role in insulin response and lipid handling.
• Glucagon receptor — associated with energy expenditure and hepatic glucose and lipid metabolism.

By recruiting the glucagon pathway alongside the two incretin pathways, Retatrutide is investigated for effects on energy expenditure in addition to the appetite- and glucose-related signaling seen with single and dual agonists. This combined profile is the primary reason it draws research interest as a distinct metabolic tool.

GLP-3 RT vs. dual and single receptor agonists

The clearest way to place GLP-3 RT in context is by the number of receptors each research compound targets. The table below summarizes the incretin landscape researchers reference most often:

Peptora carries research-grade versions of several of these compounds, including GLP-3 RT, Tirzepatide (GLP-2 TRZ), and Cagrilintide (CAGRI), each accompanied by its own batch-specific certificate of analysis.

What the research explores

In laboratory settings, GLP-3 RT is most often studied across a handful of interconnected areas:

• Metabolism — how simultaneous GLP-1, GIP, and glucagon signaling influences glucose and lipid handling in research models.
• Appetite regulation — satiety and food-intake signaling associated with incretin-receptor activity.
• Body-weight models — composition and weight endpoints in preclinical research.
• Energy expenditure — the glucagon-linked pathway that differentiates triple agonism from dual and single agonism.

Purity, testing, and certificates of analysis

In research, the reliability of a result depends on the identity and purity of the material behind it. Every batch of GLP-3 RT from Peptora is HPLC-verified to 99%+ purity, confirmed by LC-MS identity testing, and screened across a full quality-control panel before release. Each order ships with a lot-specific certificate of analysis (COA) so the material can be matched to its documentation.

Researchers often choose Peptora precisely because this documentation is standard rather than optional. To understand what each figure on a report means, see the guide on purity and certificates of analysis and the overview of testing standards.

Handling GLP-3 RT in the laboratory

GLP-3 RT is supplied as a lyophilized (freeze-dried) powder. Before research use it is reconstituted with bacteriostatic water, which is sold separately. Proper handling preserves peptide integrity and the validity of downstream work:

1. 1Allow the sealed vial to reach room temperature before opening.
2. 2Add bacteriostatic water slowly against the vial wall; swirl gently and do not shake.
3. 3Let the powder dissolve fully before drawing.
4. 4Store the reconstituted solution refrigerated and protected from light.

Full step-by-step protocols live in the reconstitution guide and the storage guide. Following them consistently is one of the simplest ways to keep research reproducible.

Scientific references

Retatrutide (LY3437943) has been investigated in Eli Lilly-sponsored clinical trials: phase 2 results have been published, and a phase 3 programme (TRIUMPH) is ongoing. The literature below is provided for educational context, per PubMed and ClinicalTrials.gov, and describes clinical and preclinical research on the compound — not the laboratory research product supplied by Peptora.

1. 1Jastreboff AM, et al. Triple-Hormone-Receptor Agonist Retatrutide for Obesity - A Phase 2 Trial. N Engl J Med. 2023;389(6):514-526. doi:10.1056/NEJMoa2301972 (ClinicalTrials.gov: NCT04881760).
2. 2Rosenstock J, et al. Retatrutide, a GIP, GLP-1 and glucagon receptor agonist, for people with type 2 diabetes: a phase 2 trial. Lancet. 2023;402(10401):529-544. doi:10.1016/S0140-6736(23)01053-X (NCT04867785).
3. 3Sanyal AJ, et al. Triple hormone receptor agonist retatrutide for metabolic dysfunction-associated steatotic liver disease: a phase 2a trial. Nat Med. 2024;30(7):2037-2048. doi:10.1038/s41591-024-03018-2 (NCT04881760).
4. 4Pasqualotto E, et al. Effects of once-weekly subcutaneous retatrutide on weight and metabolic markers: a systematic review and meta-analysis. Metabol Open. 2024;24:100321. doi:10.1016/j.metop.2024.100321.
5. 5Abdul-Rahman T, et al. The power of three: Retatrutide's role in modern obesity and diabetes therapy. Eur J Pharmacol. 2024;985:177095. doi:10.1016/j.ejphar.2024.177095.
6. 6Katsi V, et al. Retatrutide - A Game Changer in Obesity Pharmacotherapy. Biomolecules. 2025;15(6):796. doi:10.3390/biom15060796.
7. 7Eli Lilly and Company. Phase 3 TRIUMPH clinical programme — e.g. NCT05882045, NCT06354660, NCT06260722.