What Is Retatrutide?
Retatrutide is a triple-agonist research peptide developed by Eli Lilly under code name LY-3437943. Here is what it is and what to look for on a COA.
Retatrutide (also referenced under the Eli Lilly compound code LY-3437943 and the internal name Triple G) is a synthetic peptide currently in clinical development as a triple agonist of the glucagon-like peptide-1 receptor, the glucose-dependent insulinotropic polypeptide receptor, and the glucagon receptor. It is among the most heavily researched peptides in the experimental peptide market.
Structure and spec
Retatrutide has the molecular formula C221H342N46O68, a molecular weight of 4731 grams per mole per PubChem CID 171390338, and CAS number 2381089-83-2. It is a 39 amino acid peptide with a fatty acid modification on a lysine residue.
FDA enforcement note
Retatrutide is part of the GLP-1 family of compounds currently under active FDA enforcement against unauthorized marketing for human use. Many US vendors sell retatrutide under code names like GLP-3, GLP3-R, RT, or Triple G rather than the actual compound name. The molecule shipped is what matters for analytical identity, not the label.
What to look for in a Retatrutide COA
A complete Retatrutide COA should confirm identity at MW 4731 g/mol. The COA should also report HPLC purity above 99 percent, name the testing lab, and include endotoxin testing. Premium vendors test across multiple sizes with multi-lab cross-checks.
Where to buy Retatrutide
See our independent ranking of every US vendor carrying Retatrutide, including those with the strongest evidence chains:
Frequently Asked Questions
Is Retatrutide legal to buy in the US?
Retatrutide is sold by US vendors strictly as a research compound for in-vitro and preclinical use only. It is not approved by the FDA for human consumption. The FDA has issued warning letters to multiple vendors marketing GLP-1 family compounds for human use.
Why do vendors sell Retatrutide under code names?
Multiple US vendors use code names (GLP-3, GLP3-R, Triple G, RT) for marketing reasons related to FDA enforcement against unauthorized labeling. The actual compound shipped is determined by molecular analysis, not the label, so identity verification on the COA is critical.
Which lab is best for verifying Retatrutide?
Laboratories in our directory that have issued Retatrutide certificates in our audits include Freedom Diagnostics, Bioviridian, BioRegen and MZ Biolabs. BioChex, which also appears on a Retatrutide certificate, is tier D: its existence and independence are not established, so its certificates score a flat 2.0. Multi-lab cross-checks (the same batch tested at multiple independent labs) is the strongest evidence pattern.