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Oxytocin: Research Overview

What is oxytocin? Oxytocin is a cyclic nonapeptide — nine amino acids closed by a disulfide bridge between cysteine residues 1 and 6 — produced endogenously in the hypothalamus and released from the posterior pituitary. Research-grade oxytocin is supplied for laboratory receptor and behavioral-model work only, not for human or veterinary use.
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Technical profile

CompoundOxytocin
ClassCyclic nonapeptide (9 amino acids); endogenous neurohypophyseal hormone
SequenceCys-Tyr-Ile-Gln-Asn-Cys-Pro-Leu-Gly-NH₂
Structural featureIntramolecular disulfide bridge between Cys1 and Cys6, forming a six-residue ring with a three-residue tail
Molecular formulaC43H66N12O12S2
Molecular weight1007.2 g/mol
CAS number50-56-6
PubChem CID439302
Form suppliedLyophilized powder, sealed vial
StorageLyophilized: 2–8 °C, protected from light.
VerificationHPLC purity ≥99%, sterility, endotoxins, heavy metals — documented on the batch COA

What does the research literature cover?

Oxytocin has one of the longest research histories of any peptide hormone, and it remains a widely used reference ligand in laboratory work. Published research covers:

Important context: these summaries describe what researchers have published about the endogenous hormone and its receptor system. They are not claims about what the research material supplied here does in humans. Research-grade oxytocin has no approved human or veterinary use.

Why purity matters for oxytocin research

Disulfide-bridged peptides are analytically demanding. Incorrectly folded material, open-chain (reduced) forms, and dimers formed through intermolecular disulfide exchange all change how a preparation behaves in a binding assay, and none of them are visible without a method that resolves them. Every VP Peptides oxytocin batch ships with a Certificate of Analysis documenting ≥99% HPLC purity, sterility, endotoxin and heavy-metal testing from independent third-party testing.

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Frequently asked questions

Is research-grade oxytocin the same as prescription oxytocin such as Pitocin?

No. Pharmaceutical oxytocin — marketed under names including Pitocin — is an approved prescription drug: a sterile, regulated injectable manufactured under pharmaceutical GMP with an approved label and clinical supervision requirements. The research-grade oxytocin supplied by VP Peptides is not that product, is not manufactured or released as a pharmaceutical, and is not a substitute for it. It is a laboratory reagent intended solely for in-vitro and preclinical receptor and behavioral-model research.

Is research-grade oxytocin approved for human use?

No. The material described on this page is not approved by the FDA or any other regulatory agency for human or veterinary use. It is supplied strictly as a research chemical for laboratory investigation, and it is not a drug, supplement, or food ingredient. The existence of approved pharmaceutical oxytocin products does not extend any approval or safety assessment to research-grade material.

What does an oxytocin Certificate of Analysis include?

Each batch COA documents HPLC purity (≥99% specification), sterility, endotoxin and heavy-metal screening results, along with batch number and test date.

How should oxytocin be stored in the lab?

Lyophilized vials should be kept at 2–8 °C and protected from light. As a disulfide-containing peptide, oxytocin solutions warrant particular attention to repeated freeze–thaw cycles.

A closer look at the receptor and neuroendocrine literature

The receptor pharmacology of oxytocin is one of the most thoroughly mapped areas in peptide research, and it is where the mechanistic literature is densest. The oxytocin receptor (OXTR) is a class A G-protein-coupled receptor, and overviews of its signalling network describe how ligand binding couples to intracellular cascades and how the receptor sits within a broader web of interacting pathways (Chatterjee et al., 2016). Because the oxytocin and vasopressin receptor families are structurally related, cross-reactivity between subtypes is a standard analytical concern in binding studies, which is one reason a well-characterised reference ligand is valued in these experiments.

A second, neuroendocrine strand concerns how the peptide moves and is regulated within the body. Oxytocin is synthesised in the hypothalamus and released from the posterior pituitary, and recent work has examined the routes by which the neuropeptide is trafficked between the brain and the periphery in animal models (Rajamannar et al., 2025). These studies are mechanistic and physiological: their readouts are receptor occupancy, signalling markers, and measured peptide distribution, rather than any downstream outcome.

One distinction is essential here. This literature describes the endogenous hormone and its receptor system as studied in cells and animals — it does not describe effects of the research-grade material supplied here, and it is not a clinical account. An approved pharmaceutical oxytocin product exists for a defined obstetric use, but that product is a regulated injectable and is entirely separate from research-grade oxytocin, which is a laboratory reagent only. As a disulfide-bridged cyclic peptide, its behaviour in an assay depends on correct folding, making a documented purity profile central to reproducible work.

Selected research references

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Research use only. All products described on this page are furnished for laboratory research purposes only and are not for human or veterinary use, not for use in food or cosmetics, and not for any diagnostic or therapeutic application. Nothing on this page is medical advice or a claim of safety or efficacy in humans. Research summaries reference publicly available preclinical literature; specific citations are listed in the references above.