Also known as Pitocin · Syntocinon · the love hormone
A 9-amino-acid cyclic hormone of labor and bonding — historically the first peptide hormone ever chemically synthesized, and the most over-marketed "love hormone."
Oxytocin is a tiny but pivotal hormone: a 9-amino-acid cyclic peptide, closed by a single disulfide bridge, released from the posterior pituitary. It drives uterine contractions in labor and milk letdown in nursing, and it acts in the brain on social behavior — the source of its "love hormone" fame. It also holds a place in scientific history: in 1953 Vincent du Vigneaud synthesized it, the first polypeptide hormone ever made in the lab, a feat that won the 1955 Nobel Prize in Chemistry and opened the door to synthetic peptide therapeutics.
Oxytocin’s established medicine is obstetric. As Pitocin it is one of the most widely used drugs in childbirth — to induce or augment labor and to control bleeding afterward — and it mediates the milk-ejection reflex during breastfeeding. Structurally it is almost a twin of vasopressin, differing in only two residues, which is why the two hormones’ effects sometimes overlap.
Its fame, though, comes from the brain. Animal and early human work tied oxytocin to pair-bonding, maternal behavior, trust, and social affiliation, and the popular press crowned it the "love hormone" or "cuddle chemical." That framing drove a wave of intranasal-oxytocin research and products promising better social functioning — in autism, social anxiety, even relationship enhancement.
The honest reckoning is more sober. Rigorous, larger trials of intranasal oxytocin — including in autism — have largely failed to reproduce the early promise, and there are real questions about how much intranasal oxytocin even reaches the brain. Oxytocin is a genuine, important hormone whose behavioral marketing ran far ahead of the evidence — a textbook case of a misunderstood molecule, which is exactly why it belongs in an honest reference.
Agonist at the oxytocin receptor (a G-protein-coupled receptor). Peripherally it contracts uterine smooth muscle and the mammary myoepithelium; centrally it modulates circuits involved in social bonding, trust, and stress, which is the basis of its behavioral research.
Behind every vial of Oxytocin is the same exacting pipeline every research peptide runs — but the chemistry plays out differently for this molecule. Here is how Oxytocin, specifically, is brought into being.
On paper, Oxytocin is C43H66N12O12S2 — about 1,007.19 daltons of precisely arranged atoms. Before a single bond is made, the target sequence, salt form, and purity threshold are written down as the contract the finished material must meet.
Assembling Oxytocin means roughly 9 coupling cycles on the synthesizer — one protected residue added at a time, which is also 9 chances for an incomplete coupling to seed a deletion impurity. It is a short sequence, which makes the build comparatively tractable — but short does not mean trivial, and purity is still won or lost downstream. Its C-terminus is amidated rather than left as a free acid — a defined modification the synthesis has to deliver, not an afterthought. It also carries cyclization and a disulfide bridge, extra steps beyond a plain chain that add both capability and cost.
The crude mixture — Oxytocin plus its deletions and side products — is then separated on preparative HPLC, and where the cut is taken decides the difference between a genuinely pure peptide and a barely-passable one. Oxytocin carries 2 cysteines, whose thiols are oxidation-sensitive and can form disulfide links — reactive chemistry that purification has to control rather than ignore.
A real batch of Oxytocin proves itself: identity confirmed by mass spectrometry against its ~1,007.19 Da, purity read directly off an analytical HPLC trace, water and counterion content measured. That batch-specific certificate of analysis is the only honest way to know what is actually in a vial of Oxytocin — and a short, cold, accountable chain of custody is how that purity survives the trip to your bench.
Oxytocin is a 9-residue cyclic peptide with a single intramolecular disulfide bond, made by solid-phase peptide synthesis — fittingly, since its 1953 chemical synthesis was the historical proof that peptide hormones could be built in the lab at all. Its small size and defined structure make it straightforward to characterize by mass spectrometry and HPLC, unlike the large folded biologics elsewhere in this catalog.
Don't judge a vial by its cake. A fluffy, good-looking lyophilized powder reflects bulking agents and freeze-drying parameters — not purity. Insist on a batch-specific certificate of analysis.
Recent clinical trials and publications mentioning Oxytocin, pulled automatically from ClinicalTrials.gov and PubMed and refreshed daily. Listings are unfiltered search results, not curated endorsements.
A 9-amino-acid cyclic hormone from the posterior pituitary that drives uterine contractions and milk letdown, and acts in the brain on social behavior. As a drug (Pitocin) it is used in labor.
It does play a role in bonding and social behavior, but the "love hormone" label is overstated. Rigorous trials of intranasal oxytocin for social conditions, including autism, have largely failed to confirm the early hype.
It was the first peptide hormone ever chemically synthesized (Vincent du Vigneaud, 1953), which won the 1955 Nobel Prize in Chemistry and helped launch the field of synthetic peptide therapeutics.
No — this is a research and educational reference, not dosing guidance.