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Compound guide
Oxytocin: what the research covers
Nine residues closed into a ring by a single disulfide bond. It differs from vasopressin at two positions, which is why nothing about its selectivity can be taken for granted.
What Oxytocin is
The sequence is Cys-Tyr-Ile-Gln-Asn-Cys-Pro-Leu-Gly-NH2, with a disulfide bridge between the two cysteines closing a six-residue ring and leaving a three-residue tail. It was the first peptide hormone to be chemically synthesised, which is part of why its pharmacology is so thoroughly documented.
Vasopressin has the same architecture and differs at only two positions. Both act on class-A G-protein-coupled receptors, oxytocin at OXTR through Gq/11, phospholipase C and calcium release, with Gi coupling reported in some systems. Cross-reactivity at the vasopressin V1a receptor is not negligible, and in any experiment attributing an effect to the oxytocin system it has to be addressed rather than assumed away.
Amino Club supplies it as the acetate salt, which matters for cell work: residual trifluoroacetate from reverse-phase purification has biological effects of its own at the concentrations it can reach.
Two fields that rarely cite each other
In smooth muscle physiology oxytocin is a century-old classical agonist. Isolated uterine strip preparations respond to it reproducibly, and that assay is still how oxytocin receptor antagonists are characterised. The mammary myoepithelial response is the other established peripheral action.
In neuroscience the literature is much newer and much less settled. Oxytocin acts centrally as a neuromodulator, with receptor distribution mapped across species and effects reported on social recognition, pair bonding, maternal behaviour and anxiety in animal models. The human literature in this area has a well-documented replication problem, and a careful reader treats the peripheral physiology and the social neuroscience as separate bodies of evidence with very different levels of confidence.
Two methodological points run through both: the V1a cross-reactivity above, and the fact that peripherally administered oxytocin crosses into the brain poorly — which makes the route by which central effects are produced a live question rather than a detail.
How Amino Club supplies it
Supplied lyophilised in sealed vials as Oxytocin Acetate, specified at 99% purity or better by HPLC with identity confirmed by mass spectrometry and released against the Certificate of Analysis for its own batch; the lab testing page documents the release sequence.
Oxytocin is among the least stable peptides in this catalogue once in solution. The disulfide bridge is open to reduction and to thiol-disulfide exchange, and aqueous solutions lose measurable potency over days even refrigerated — a well-documented formulation problem rather than a theoretical one. Laboratories store the dry powder below −18 °C, prepare single-use working volumes, keep them cold and dark, and avoid reducing agents in the buffer. Diluents are under reconstitution supplies.
Related reading
Oxytocin sits in the sexual health and reproductive research peptides group with PT-141, kisspeptin, gonadorelin, HCG and HMG. Its central actions place it closer to the cognitive group than the rest of that list.
Every guide is indexed in the research library. Certificates and storage are covered on the FAQ, quantity pricing through bulk and wholesale.
Research use only
Oxytocin supplied by Amino Club is a laboratory reference material. It is not a medicine, not a supplement, and not for human or veterinary use, and no dosing guidance or administration protocol is provided. The full terms are in the research use policy.