Retatrutide (GLP3-RT): Research Compound Profile

Retatrutide, catalogued at livvmore under the house code GLP3-RT, is a synthetic 39-residue peptide supplied strictly as a laboratory research reference material. This profile sets out its verified chemical identity, structural features, physical characteristics, and the analytical methods used to confirm identity and purity per batch. Every figure below is drawn from public chemistry registries so that a receiving laboratory can reconcile the reference material against an independent record before any bench work begins.

Compound identity and CAS registry

Retatrutide (GLP3-RT) carries CAS Registry Number 2381089-83-2. It is indexed in PubChem, where the free peptide is recorded under CID 171390338 and the sodium salt under CID 171934787. In the primary literature the compound also appears under the development code LY3437943. It is classified as a synthetic peptide of the incretin family and, in published pharmacology, as a triple receptor agonist described at the GIP, GLP-1, and glucagon receptors; this classification denotes the molecule’s mechanistic category in the literature and is not a statement of any outcome. All registry identifiers should be cross-checked against a Certificate of Analysis on receipt.

Molecular formula, weight, and structure

The molecular formula of Retatrutide is C₂₂₁H₃₄₂N₄₆O₆₈, corresponding to a monomeric molecular weight of approximately 4731 g/mol for the free peptide (registry values cluster near 4731.3 to 4731.4 g/mol depending on the salt form). The molecule is a linear single-chain peptide of 39 amino acids terminating in a C-terminal amide. Its most distinctive structural feature is a C20 fatty diacid moiety attached at the lysine in position 17 through a gamma-glutamic acid and an aminoethoxyethoxyacetic acid (AEEA) linker. This lipidation motif is characteristic of lipidated incretin-class peptides and is associated with albumin binding, a physicochemical property described in the published literature.

Amino-acid sequence and modifications

The published sequence incorporates several non-canonical residues, including two alpha-aminoisobutyric acid (Aib) substitutions and an alpha-methyl-leucine, which are structural modifications that raise resistance to enzymatic degradation. Written in single-letter and modified-residue notation, the backbone reads: Tyr-Aib-Gln-Gly-Thr-Phe-Thr-Ser-Asp-Tyr-Ser-Ile-(alpha-Me-Leu)-Leu-Asp-Lys-(C20 diacid-gamma-Glu-AEEA linker)-Ala-Gln-Aib-Ala-Phe-Ile-Glu-Tyr-Leu-Leu-Glu-Gly-Gly-Pro-Ser-Ser-Gly-Ala-Pro-Pro-Pro-Ser-NH₂. Because the sequence contains modified residues and a branched lipid conjugate, standard automated sequence prediction tools may not resolve it fully; mass-based confirmation is the reliable route.

Appearance, solubility, and solution preparation for bench use

Retatrutide (GLP3-RT) is typically supplied as a lyophilised white to off-white powder. As a lipidated peptide it is generally handled in aqueous buffers for bench work; laboratories commonly dissolve lyophilised peptide reference material with sterile or sterile water and, where a lipid conjugate reduces aqueous solubility, a mildly alkaline buffer is used to bring the material fully into solution before dilution. dissolved stocks are best held cold and protected from repeated repeated freezing and thawing, which can drive aggregation of long-chain peptides. The lyophilised solid is normally stored at -20 degrees C or colder, desiccated and away from light. These notes describe handling of the reference material at the bench only and are not use instructions.

Confirming identity and purity by LC-MS

Because Retatrutide is a large modified peptide, orthogonal analytical methods are the standard for characterisation. Reversed-phase HPLC (RP-HPLC) resolves the main peak from truncated, deletion, and oxidised sequence variants and yields a percentage purity by peak area. Liquid chromatography coupled to mass spectrometry (LC-MS), and high-resolution mass spectrometry (HRMS), then confirm identity by matching the observed monoisotopic or average mass against the theoretical mass derived from C₂₂₁H₃₄₂N₄₆O₆₈. For a peptide of this size the multiply charged ion envelope is deconvoluted to a single intact mass, and any mismatch flags a synthesis or handling issue. livvmore materials are identity- and purity-tested at the USC Alfred E. Mann Multi-Omics Mass Spectrometry Core, a university laboratory, by LC-MS/HRMS on a per-batch basis, with the resulting Certificate of Analysis published for each lot. Reading a COA means checking that the stated batch, the measured mass, and the purity percentage all correspond to the compound named on the label.

Related research peptides in the catalogue

Within the incretin research family, Retatrutide (GLP3-RT) sits alongside Semaglutide (GLP1-SM) and Tirzepatide (GLP2-TZ). The three differ in receptor selectivity, chain length, and lipidation chemistry, which is why identity confirmation by mass is essential rather than optional when comparing reference materials. The full set is grouped in the GLP research peptide collection, each entry carrying its own batch documentation.

For laboratory research use only. Not for human or veterinary use.

Frequently asked questions

What is the CAS number of Retatrutide (GLP3-RT)?

Retatrutide (GLP3-RT) has CAS Registry Number 2381089-83-2. It is also indexed in PubChem as CID 171390338 (free peptide) and CID 171934787 (sodium salt), and appears in the literature under the development code LY3437943.

What is the molecular formula and molecular weight of Retatrutide?

Retatrutide (GLP3-RT) has the molecular formula C221H342N46O68 and a molecular weight of approximately 4731 g/mol for the free peptide, with registry values near 4731.3 to 4731.4 g/mol depending on the salt form.

How many amino acids does Retatrutide contain?

Retatrutide (GLP3-RT) is a synthetic single-chain peptide of 39 amino acids with a C-terminal amide. It includes non-canonical residues such as two alpha-aminoisobutyric acid (Aib) substitutions and a C20 fatty diacid conjugated at position 17 through a gamma-glutamic acid and AEEA linker.

How is the identity and purity of Retatrutide verified?

Identity and purity of Retatrutide (GLP3-RT) are verified by reversed-phase HPLC for purity by peak area and by LC-MS or high-resolution mass spectrometry (HRMS) to match the measured intact mass against the theoretical mass from C221H342N46O68. livvmore batches are tested at the USC Alfred E. Mann Multi-Omics Mass Spectrometry Core, with a per-batch Certificate of Analysis published for each lot.

How should lyophilised Retatrutide reference material be stored at the bench?

Lyophilised Retatrutide (GLP3-RT) is typically stored at -20 degrees C or colder, desiccated and protected from light. dissolved stocks are held cold and protected from repeated repeated freezing and thawing to limit aggregation. These are laboratory handling notes for the reference material only.