Retatrutide

Retatrutide is a modified 39-residue peptide studied as an agonist at glucagon, GIP and GLP-1 receptors.

Identity

Sequence

H-Y[Aib]QGTFTSDYSI[αMeLeu]LDK[K*]AQ[Aib]AFIEYLLEGGPSSGAPPPS-NH2

Residues

39

Molecular formula

Not recorded

Average molecular weight

Not recorded

CAS number

Not recorded

Strengths

5–60 mg

Other names

LY3437943

The sequence comes from ChEMBL; a PubChem record, formula and CAS number were not confirmed in the consulted primary databases, so no molecular weight is given. αMeLeu means α-methyl-L-leucine. K* marks residue 17, which ChEMBL records as carrying a fatty diacid attached through γ-glutamic acid and a linker; because that record labels the residue lysine but draws a shorter side chain, its exact structure is not stated here.

Identity data from: ChEMBL CHEMBL5095485

Research overview

Retatrutide, also identified as LY3437943, is a peptide with a recorded chain of 39 residues and an amidated C terminus. Its sequence contains Aib residues, αMeLeu and a modified residue designated K*. The two Aib residues occupy positions 2 and 20, while αMeLeu, meaning α-methyl-L-leucine, occurs at position 13. The amino terminus is free and the first residue is tyrosine. The sequence also includes lysine at position 16, directly before K*. Positions 35–39 are Ala-Pro-Pro-Pro-Ser, with three consecutive proline residues close to the amidated end and serine as the final residue [1]. ChEMBL records a fatty diacid connected to K* through γ-glutamic acid and a linker. The record’s residue label and side-chain drawing disagree, so the exact structure of this attachment is not specified here.

The discovery paper describes agonism at three hormone receptors: the glucagon receptor (GCGR), the glucose-dependent insulinotropic polypeptide receptor (GIPR) and the glucagon-like peptide-1 receptor (GLP-1R). In the reported in vitro experiments, LY3437943 showed similar activity at GCGR and GLP-1R and greater activity at GIPR [1]. The same report also included mouse experiments alongside the in vitro characterization of these three receptor targets [1].

A subsequent publication reported a phase 2 clinical study of retatrutide [2].

Laboratory storage and handling

Store the closed container cold, dry and protected from light under the conditions specified for the lot. Let it reach room temperature before opening to limit condensation. Avoid repeated freezing and thawing of laboratory stocks. Record storage history and lot identity alongside experiments, and use standard laboratory protective equipment when handling the material.

Questions about Retatrutide

References

1. 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 Metab 2022. PMID 35985340
2. Triple-Hormone-Receptor Agonist Retatrutide for Obesity - A Phase 2 Trial. N Engl J Med 2023. PMID 37366315

Identity data checked on 2026-09-24. Literature summaries describe published research models and are not specifications of any product lot.