Retatrutide CAS, molecular weight and sequence: analytical reference for lab procurement

For analytical procurement, the durable identifiers are CAS 2381089-83-2, formula C221H342N46O68 and average mass about 4731 g/mol. FDA GSRS UNII NOP2Y096GV is the public regulatory substance key; PubChem CID 171934787 is a convenient structure card for the sodium-salt presentation of the same formula family.

Do not confuse the GSRS protein-only calculated mass (~4091 Da on the protein view, which omits the fatty-acyl chemistry) with the alternative chemical definition mass of 4,731.36. Procurement and LC-MS work should use the chemical definition that includes the side chain.

1. CAS 2381089-83-2 on the PO and receiving log.
2. Formula C221H342N46O68 and MW ~4731 g/mol on the analytical worksheet.
3. Lot number from the vial tied to a lot-specific report when one is published.

FDA GSRS publishes the protein subunit as YAQGTFTSDYSILLDKKAQAAFIEYLLEGGPSSGAPPPS. The finished chemical entity replaces selected alanines with 2-methylalanine (Aib) and attaches a long-chain fatty diacid via a γ-Glu / AEEA linker on a lysine side chain. KEGG D12430 therefore prints X in the Aib positions. Vendor pages that quote ~4090 g/mol are usually repeating the backbone-only calculation; pages that quote ~4731 g/mol are aligned with the full chemical definition used by GSRS and PubChem.

This page is an analytical identity reference. It does not describe biological activity, dosing, or any use in humans or animals.

For a research vial, a useful certificate names the lot (or lab accession), the laboratory, HPLC purity with method detail, measured quantity for the tested sample, and—when identity is claimed—MS evidence near the ~4731 Da charge-state series. Cap-color labels are not lot numbers; when a report is keyed only by a cap-color description, use the lab accession as the durable ID.

Counterfeit or recycled certificates often fail a lab-portal lookup or show an ion series that cannot belong to C221H342N46O68. See our separate guide on counterfeit retatrutide identity testing for the failure modes.

1. Lot or accession matches the vial or packing list.
2. HPLC purity with method stated.
3. Measured mg for the tested sample.
4. MS ions consistent with ~4731 Da when identity is claimed.
5. Lab lookup or written lab confirmation when available.

Published retatrutide lot pages currently include Vanguard Laboratory sample “Lime Green Cap” / accession V260212-5 002 with a lab-hosted verify record, and Vanguard Laboratory lot RT3042126 with written lab authenticity confirmation dated 2026-11-01. Each result applies only to the tested sample named on that report.

US/CA/MX self-serve orders use US fulfillment. Eligible overseas institutional buyers use /international-lab-orders. Self-serve shipping is not offered to Australia, New Zealand, or OFAC-sanctioned destinations.