GLP-3R

GLP-3R Research Overview

Retatrutide is a once-weekly peptide that activates GLP-1, GIP and glucagon receptors together. Phase 2 data showed about 24 percent weight loss at 48 weeks, the largest figure reported for any single compound, but it is still years from approval.

Also known as: LY3437943, Triple G, GGG tri-agonist

Background

Retatrutide is Eli Lilly's follow-up to tirzepatide: a single peptide that activates three receptors, GLP-1, GIP and glucagon. The glucagon component is the new piece. Glucagon receptor activation raises energy expenditure and pushes the liver to burn fat, which in theory adds a calories-out lever to the appetite lever that GLP-1 drugs already pull. It is a lipidated peptide dosed once weekly, same as its predecessors.

The Phase 2 obesity trial published in 2023 is why everyone is paying attention. A liver fat substudy showed most participants on the higher doses reaching normal liver fat. A separate Phase 2 in type 2 diabetes produced strong HbA1c reductions on top of the weight loss.

Phase 3 (the TRIUMPH program) is ongoing. Lilly reported topline results from one of those trials in late 2025 showing weight loss in the high 20s percent range at 68 weeks, but that came from a press release, not a peer-reviewed paper. There is no approved product anywhere, so everything sold as retatrutide is grey-market material of unverified purity, and the hype around it has attracted plenty of low-quality product.

Mechanistic Profile

Three receptors, three jobs. GLP-1 activation lowers appetite, slows gastric emptying and improves glucose-dependent insulin secretion. GIP activation adds to appetite suppression, may improve fat tissue metabolism and appears to reduce nausea. Glucagon receptor activation is the distinctive part: it increases resting energy expenditure, drives fat oxidation in the liver and lowers liver fat. On its own, glucagon would raise blood glucose, but the two incretin components offset that. Retatrutide is deliberately a weak GLP-1 agonist molecule for molecule and a stronger GIP and glucagon agonist, a balance chosen so that the metabolic effects come through without hyperglycemia.

Reported Research Findings

• (human RCT)

• Over 80 percent of participants with fatty liver on the higher doses reached normal liver fat by week 48 (Phase 2 substudy). (human RCT)

• Lowered HbA1c by up to about 2 percentage points in type 2 diabetes alongside roughly 17 percent weight loss at the top amount (Phase 2). (human RCT)

• Sponsor-reported Phase 3 topline results in late 2025 exceeded the Phase 2 figures; full peer-reviewed data still pending. (human RCT)

• Heart rate rose by several beats per minute early in treatment and drifted back toward baseline over time. (human RCT)

Analytical Validation, Formulation and Storage

• Purity: 99% or higher as verified by HPLC, with a third-party certificate of analysis available per batch.

• Formulation: lyophilised (freeze-dried) powder in a sterile sealed glass vial, to be reconstituted with an appropriate solvent for laboratory use.

• Reported half-life: About 6 days (Phase 1 estimate).

• Storage: keep lyophilised material cool, dark and dry (long-term at or below -20 °C). Store reconstituted solutions refrigerated, avoid repeated freeze-thaw cycles and use within laboratory-defined windows.

Selected Literature

• Triple-hormone-receptor agonist retatrutide for obesity, a phase 2 trial. New England Journal of Medicine, 2023.

• 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.

• Triple hormone receptor agonist retatrutide for metabolic dysfunction-associated steatotic liver disease: a randomized phase 2a trial. Nature Medicine, 2024.

• 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.

Cloud Aminos supplies GLP-3R as a high-purity research material intended strictly for controlled laboratory use in vitro or in established animal models. This compound is not approved as a drug, diagnostic or dietary ingredient and is not manufactured, packaged or marketed for human consumption, self-experimentation, clinical application or any use outside properly designed and ethically approved research protocols.