What Oxytocin is
Oxytocin is a nonapeptide with a disulfide bridge, synthesised in the hypothalamus and released from the posterior pituitary. It was the first peptide hormone to have its structure determined and then be chemically synthesised, work that earned a Nobel Prize in 1955 and effectively opened peptide chemistry as a field. Nearly everything else in this catalogue exists downstream of that.
- OxytocinNonapeptide, disulfide-bridged
- Oxytocin receptor (OXTR)Gq-coupled GPCR
- PLC → IP₃ → Ca²⁺Central and peripheral populations differ
- Social and neuroendocrine modelsPreclinical and clinical
Mechanism as described in published research. Nothing here describes an effect in a person — these compounds are supplied for laboratory research use only.
Receptor signalling and a design caution
Oxytocin acts at the oxytocin receptor, a G-protein-coupled receptor. The critical detail for study design is its relationship to vasopressin: the two peptides differ by only two residues, and their receptors are correspondingly similar. Cross-reactivity between oxytocin and vasopressin receptor subtypes is a real and frequently underestimated confounder.
Any protocol attributing an effect specifically to oxytocin signalling has to address that possibility, usually with selective antagonists. It is a recurring theme in the critical literature on social-behaviour findings, where the effect sizes are often modest and the receptor selectivity assumptions do a lot of quiet work.
What the literature covers
Research areas include:
- Social behaviour and affiliation models — the largest and most contested literature.
- Oxytocin receptor pharmacology, including vasopressin cross-reactivity.
- Neuroendocrine regulation — the classical physiological roles.
- Peptide chemistry history — oxytocin as the first synthesised peptide hormone.
Identity and verification
Oxytocin has the molecular formula C43H66N12O12S2 and a molecular weight of 1007.2 g/mol (CAS 50-56-6). Identifiers matter more here than in most categories: research compounds are sold under trade names, development codes and abbreviations that do not always refer to the same molecule, and a formula is unambiguous where a name is not.
Every lot is tested by an independent laboratory before release. Our certificate library covers the lots currently in stock.
We use two laboratories because purity and identity are different questions. Vanguard Laboratory is ISO/IEC 17025:2017 accredited (A2LA #6377.01.01) and reports chromatographic purity and net quantity with a stated measurement uncertainty. Freedom Diagnostics reports HPLC-UV purity together with LC-MS identity confirmation — the test that catches a substituted compound rather than merely an impure one. A sample can be 99% pure and still be the wrong molecule. How we test →
Handling, reconstitution and storage
Oxytocin ships lyophilized — freeze-dried to a solid and sealed under vacuum — which is what makes it stable in transit rather than a solution racing a clock. Reconstitute with bacteriostatic water, added slowly down the inside wall of the vial rather than directly onto the powder, then swirled gently. Do not shake: mechanical shear is one of the few things that reliably degrades a peptide in the lab.
Final concentration is a function of the volume added, not of the compound, so the same vial can be prepared at very different concentrations. The reconstitution calculator works out the volume for a target concentration and the reconstitution guide covers the procedure. Store lyophilized vials at −20 °C (−4 °F) protected from light; refrigerate once in solution, and see the storage and stability guide for how long reconstituted material holds.
Common questions
Why is oxytocin historically significant?
It was the first peptide hormone to have its structure determined and then be chemically synthesised — work recognised with the 1955 Nobel Prize in Chemistry, which effectively opened peptide chemistry as a field.
How does oxytocin relate to vasopressin?
They differ by only two residues, and their receptors are correspondingly similar. Cross-reactivity between the two receptor systems is a genuine confounder that study designs need to control for.
Why is the social-behaviour literature contested?
Effect sizes are frequently modest and many designs rest on receptor-selectivity assumptions that vasopressin cross-reactivity complicates. A good deal of the critical literature is about exactly that.
What is oxytocin's structure?
A nonapeptide — nine residues — with a disulfide bridge forming a ring, synthesised in the hypothalamus and released from the posterior pituitary.
Where to get it
Buy research-grade Oxytocin — independently tested, certificate published, shipped from Miami with cold-chain packaging. Current pricing for every size is on the price list, and we ship worldwide.
Research use only
Everything referenced here is supplied strictly for laboratory research. These compounds are not drugs, foods, cosmetics or medical devices, are not for human or veterinary use, and are not approved for diagnostic or therapeutic application. Mechanisms are described as studied in preclinical and laboratory research; nothing above describes dosing, treatment or clinical outcome.
