What Is Retatrutide (LY3437943)?
Retatrutide, development code LY3437943, is an engineered peptide described in published literature as a triple agonist of the GLP-1, GIP, and glucagon receptors. Researchers also encounter it under the informal labels "reta", "reta peptide", and "GLP-3". This page explains what the compound is, how the literature characterises it, and how Amino Fuel Labs documents each lot. Research use only — not for human consumption.
Identity and development background
Retatrutide is a synthetic 39-amino-acid peptide analogue developed under the Eli Lilly code LY3437943. It belongs to the incretin-analogue family alongside semaglutide and tirzepatide, but adds glucagon receptor activity to the GLP-1 and GIP profile. That third receptor is why the compound is frequently described as a triple agonist, and why researchers informally call it "GLP-3" even though no distinct glucagon-like peptide-3 hormone exists. The correct designation is retatrutide, and common misspellings include retatutride and retratutide.
Receptor profile described in the literature
Published preclinical and clinical articles characterise retatrutide's binding at all three receptors and report pharmacokinetics consistent with weekly study intervals. GLP-1 and GIP engagement are the incretin arms studied in earlier dual-agonist work; glucagon receptor engagement is the differentiating arm, discussed in the literature in the context of energy expenditure in study models. Amino Fuel Labs summarises these published characterisations only and makes no claim that retatrutide treats, cures, diagnoses, heals, or prevents any condition in humans.
Regulatory and availability status
Retatrutide is investigational. It has not been approved by the FDA or any comparable regulator, and it is not available as a prescription medicine. Material supplied by Amino Fuel Labs is research-grade peptide intended exclusively for laboratory research personnel. We do not supply retatrutide for personal use, and nothing on this site should be read as guidance for use in humans.
How each lot is documented
Every retatrutide lot is released only after reverse-phase HPLC verification at an independent analytical laboratory. The Certificate of Analysis records peptide identity, lot number, manufacture and retest dates, appearance, and measured purity, and the lot on the vial matches the lot on the COA. Vials ship lyophilized with cold-chain-aware packaging so investigators receive material in the condition the documentation describes.
Related research peptides
Related research articles
Lab reports & documentation
Frequently asked questions
What is retatrutide?
An investigational synthetic peptide, development code LY3437943, described in the literature as a triple GLP-1 / GIP / glucagon receptor agonist. It is supplied here for laboratory research only.
Is retatrutide a peptide?
Yes. It is a synthetic peptide analogue, supplied lyophilized in sealed vials.
Is retatrutide a GLP-1?
It engages the GLP-1 receptor, but it is not a selective GLP-1 agonist — it also engages GIP and glucagon receptors.
What does 'GLP-3' mean?
It is informal shorthand researchers use for retatrutide's triple-receptor profile. There is no separate glucagon-like peptide-3 hormone.
Is retatrutide for research use only?
Yes — laboratory research only, not for human consumption.