We report net peptide content, not just purity — so the milligrams you dose aren't padded with water and counter-ion. RP-HPLC purity and ESI-MS identity, on a lot-numbered COA.
Net peptide content, not just purity — RP-HPLC + ESI-MS, lot-numbered COA.
Net peptide content on every lot's COA.
Reading a Peptide HPLC Trace — A 5-Minute Field Guide for Bench Scientists. Read our briefing →
Reading a peptide HPLC trace — a field guide. Read →
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Posterior-pituitary neuropeptide hormone · regulated
Lyochem primary owner
This Lyochem page is the primary SEO owner for research labs, CROs, and method-development teams qualifying Oxytocin as a documented research-standard lot. The page should answer whether the buyer can review HPLC purity, identity confirmation, lot continuity, stability handling, and assay-fit documentation before ordering.
Overview
A cyclic nonapeptide, Oxytocin (Cys-Tyr-Ile-Gln-Asn-Cys-Pro-Leu-Gly-NH₂) owes its receptor-binding activity to an intramolecular disulfide linking Cys1 and Cys6; this bridge folds the first six residues into a constrained ring while leaving a three-residue amidated tail, and its correct formation is the primary identity criterion for any authentic lot. Hypothalamic magnocellular neurons of the paraventricular and supraoptic nuclei synthesize the hormone, which is stored in and secreted from the posterior pituitary. It carries prescription-drug approval across major jurisdictions for obstetric use (induction of labor, management of postpartum hemorrhage) and serves as a research tool in pair-bonding, stress-axis, social-behavior, and smooth-muscle models. Lyochem supplies Oxytocin as a lyophilized reference standard at ≥99.0% HPLC. Because the correct product depends on oxidative folding of the linear precursor toward the intended intramolecular disulfide rather than scrambled intermolecular species, characterization is essential: peak-integrated RP-HPLC for purity, ESI-MS confirming the oxidized mass of 1007.19 g/mol (2 Da below the reduced linear form), plus Karl Fischer water content and counter-ion determination. Given the compound's controlled status internationally, buyers must hold licensing appropriate to their destination, and the release documentation supports academic and research qualification.
Applications & buyer fit
Biotech R&D Groups
Preclinical biotech and pharmaceutical discovery teams sourcing characterized peptides for receptor-pharmacology, screening, and method-development campaigns.
Academic Laboratories
Universities, medical schools, and government research institutes qualifying a reference standard for a method-development or in vivo workflow.
Every release ships with its own batch-specific CoA — identity, purity, and the analytical scope agreed at quote stage, tied to the exact lot you receive.
Review a representative batch CoA before you order, so you can confirm the packet matches what your method or sponsor audit needs.
Supplied strictly as a research reagent to research institutions — not a finished dosage form and not for human administration. Buyer qualification runs at the inquiry stage.
Specifications
Documentation available on request
Regulatory note
This highly regulated hormone carries prescription-drug approval in essentially every major jurisdiction, under the brand names Pitocin and Syntocinon as well as generic equivalents. We supply it exclusively to qualified buyers holding appropriate licensing in their jurisdiction. Before any order proceeds, a compliance review is required, and import authorization documentation may be needed for the destination market.
Frequently asked questions
Ring closure between the two cysteines removes two hydrogen atoms, so the oxidized cyclic peptide is 2 Da lighter than its reduced linear form; mass spec reading the cyclized mass is the primary confirmation the disulfide formed intramolecularly. RP-HPLC against a reference standard adds an orthogonal check, since the cyclic and reduced forms elute at different retention times. An analyst should verify both the expected cyclized mass and a single dominant peak at the reference position, because only the disulfide-bridged form binds receptor, and the linear species is effectively inactive contaminant.
Oxidative folding can misfire toward disulfide links between molecules rather than the intended intramolecular ring, producing dimers and higher oligomers. These byproducts appear at multiples of the monomer mass by ESI-MS and as additional, later- or differently-eluting peaks by RP-HPLC, so both methods flag them. For reference-standard use the analyst wants a batch dominated by the correctly cyclized monomer, with oligomeric species low; reviewing the mass envelope and chromatogram for these features confirms the oxidation favored intramolecular cyclization before the material is used to prepare dosing solutions.
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