Retatrutide (LY3437943) is a synthetic, lipidated 39-residue peptide. It incorporates three non-coded residues—α-aminoisobutyric acid (Aib) at positions 2 and 20 and α-methyl-L-leucine at position 13—and Lys17 is acylated with icosanedioic acid (C20 diacid) through a γ-glutamyl–8-amino-3,6-dioxaoctanoyl linker. The C-terminal segment GPSSGAPPPS-NH2 is shared with exendin-4-derived sequences.

Retatrutide has been characterized as a single-molecule agonist of three class B G protein-coupled receptors: the glucose-dependent insulinotropic polypeptide receptor (GIPR), the glucagon-like peptide-1 receptor (GLP-1R) and the glucagon receptor (GCGR). In vitro it was reported to show balanced GCGR and GLP-1R activity with greater GIPR activity, and cryo-EM structures of retatrutide bound to each Gs-coupled receptor have been used to rationalise this triple agonism. In differentiated human adipocytes it has been used to stimulate lipolytic glycerol-release responses.

Retatrutide is cited in incretin- and glucagon-receptor pharmacology, receptor cross-reactivity and signalling studies, structural biology of class B GPCRs, adipocyte cell models, and LC-HRMS analytical methods for lipidated peptide agonists. Lyophilized material is hygroscopic and should be stored desiccated and protected from light.

Research use only. This material is sold for in-vitro laboratory research and development purposes exclusively. It is not a drug, food, or dietary supplement, has not been evaluated by the FDA, and must not be used in humans or animals.