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GLP-3 (RT) is Open Science’s product name for retatrutide, also identified in published literature as LY3437943. This synthetic 39-amino-acid peptide is designed to activate the GIP, GLP-1, and glucagon receptors. It is supplied as a lyophilized powder exclusively for laboratory research and is not intended for human or animal use.

The sodium salt of retatrutide has a molecular weight of approximately 4,731 g/mol and a molecular formula of C₂₂₁H₃₄₂N₄₆O₆₈. Its structure includes a C20 fatty diacid component attached at lysine-20 through a linker.

The primary distinction is the number of receptor pathways studied. Semaglutide targets the GLP-1 receptor, while tirzepatide targets both the GIP and GLP-1 receptors. Retatrutide is studied as a triple agonist because it also targets the glucagon receptor. Comparative research involving these compounds remains ongoing.

Each batch undergoes independent laboratory analysis before release. Testing includes peptide identity, HPLC purity, and bacterial endotoxins. The tests performed and their corresponding results are documented on the batch-specific Certificate of Analysis available through our product page.

Open Science requires a minimum HPLC purity result of 99% for GLP-3 (RT). Because results can vary slightly between production lots, customers should consult the Certificate of Analysis for the exact purity reported for their batch.

Keep the sealed vial protected from light, moisture, and heat. For extended storage, the lyophilized material should be maintained at −4°F (−20°C) in a laboratory freezer. Avoid unnecessary freeze–thaw cycles, which may affect peptide integrity. The manufacturer indicates a frozen storage period of approximately 12–24 months for sealed material; Open Science release testing does not independently determine shelf life.

Peer-reviewed publications can be found through PubMed by searching for “retatrutide” or its development code, “LY3437943.” Relevant literature includes receptor-characterization research by Coskun and colleagues, phase 2 studies led by Jastreboff and Rosenstock, and a phase 2a study led by Sanyal. Links to selected publications are available in the research section above.