Oxytocin Peptide
The first peptide hormone anyone ever built by hand instead of grinding out of a gland. That synthesis won the 1955 Nobel, and two residues separate it from vasopressin, a completely different hormone.
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For research use only. Not for human or veterinary use.
What Oxytocin Peptide is
The plain-language version, first.
The molecule that proved peptides could be built rather than harvested.
Oxytocin is a nonapeptide hormone with the sequence CYIQNCPLG and a C-terminal glycine amide, cyclised by a disulfide bond between Cys1 and Cys6, with molecular formula C43H66N12O12S2, molecular weight 1007.19 and CAS number 50-56-6. It differs from vasopressin at two positions only, isoleucine at position 3 and leucine at position 8, and is authorised in Canada as a prescription injection indicated for labour and postpartum uterine control.
Before 1953, if you wanted a peptide hormone you took it out of an animal. Grinding glands was the whole industry.
Then Vincent du Vigneaud built oxytocin from scratch, atom by atom, and collected the 1955 Nobel Prize for it.
This molecule is where synthetic peptide chemistry begins. Everything else on this shelf descends from that proof.
Nine residues with a ring in the middle, made by your hypothalamus, released by your pituitary, with a genuine clinical history in obstetrics running back generations.
And here is the party trick: change just two residues and you get vasopressin, which manages your blood pressure and kidneys instead.
Two letters between hugging and hydration. Molecules do not care how important the difference feels.
oxytocin peptide sequence and structure
Mechanism studied, not outcome promised.
The oxytocin receptor is a GPCR coupled to Gq. Activation runs phospholipase C, which releases calcium inside the cell, and calcium is what makes a smooth muscle cell shorten. That's the contraction pathway in one line.
Two residues separate oxytocin from vasopressin, so their receptors read each other's mail. Cross reactivity at higher concentrations is expected rather than surprising, and it's the reason synthetic manufacture became the standard.
In the periphery it behaves like a hormone. In the brain it behaves like a neuromodulator, released locally and acting close to home. Most of that central work is animal work, and the popular version of it runs a long way ahead of the data.
Two residues away from a hormone with an entirely different job.
The receptor story is textbook: oxytocin binds its receptor, smooth muscle in specific tissues responds, and the obstetric uses follow directly from that.
The brain story is where the modern noise lives.
Oxytocin signalling in the brain is real, studied, and stubbornly complicated. The love hormone framing is marketing wearing a lab coat.
The genuinely interesting problem is delivery: peptides do not cross the blood-brain barrier politely, so how much peripheral oxytocin reaches brain receptors is a live methodological fight in the actual literature.
Here's the honest part. The famous behavioural findings have had a rough decade of replication attempts.
The body of work that made oxytocin a headline is precisely the body of work the replication crisis chewed hardest.
The research so far for Oxytocin Peptide
Where the evidence is thin, we say so.
Seventy years of obstetric use. An FDA approval under NDA 018261 dating to November 1980. Health Canada DINs 00497398, 02139561 and 02550199, all marketed, all prescription. And chemistry confirmed twice over, since PubChem and the FDA label agree on C43H66N12O12S2 and 1007.19 without a rounding argument between them.
A human evidence base that matches the popular reputation. The trust and bonding literature is younger, smaller and far less settled than the uterine file, and much of the central receptor mapping sits in animals. Also missing, and this one surprises people: any listing at all on the WADA Prohibited List.
The most instructive fact about oxytocin is not what it does but what its near identity to vasopressin forced manufacturers to do. Both hormones are nonapeptides cyclised by a Cys1 to Cys6 disulfide, and they diverge at only positions 3 and 8, isoleucine and leucine in oxytocin against phenylalanine and arginine in vasopressin. Historically both were recovered from posterior pituitary extracts of livestock, where separating two molecules that similar was an unreliable proposition, and residual antidiuretic activity in an oxytocic preparation is not a trivial impurity in an obstetric setting. The FDA label for Pitocin therefore states that the product is prepared synthetically to avoid possible contamination with vasopressin. That single sentence is a structural fact rendered as a manufacturing decision, and it explains why sequence identity matters better than any diagram does.
A century of clinical history, and a modern hype cycle it never asked for.
Split the file in two and it makes sense.
The clinical half is old and solid. Obstetric use under supervision, well characterised, decades deep. Real medicine, in hospitals, on a different product than a research vial.
The behavioural half is the cautionary tale of a generation. Trust games, nasal sprays, bold headlines, and then years of failed replications.
That second half is taught in methods courses now, as the example of what small-sample behavioural science does to a molecule's reputation.
A Nobel origin, a real clinical legacy, and a pop-science decade it is still living down. All three on one nine-residue molecule.
Oxytocin · 2mg and 5mg vials · lyophilised powder · Canadian stock, ships from BC
Oxytocin Peptide specs
The chemistry, exactly as released.
Who studies Oxytocin Peptide
Who tends to order this one, and why.
A research compound does not have one audience. It has a handful of rooms where the same question keeps coming up, and the question is a different question in each of them.
Receptor pharmacology
Labs mapping oxytocin receptor binding, Gq coupling or cross reactivity with vasopressin receptors, where having the native nonapeptide as the reference ligand beats reaching for an analogue.
Smooth muscle and calcium work
Bench work on phospholipase C signalling and intracellular calcium release in smooth muscle preparations, where oxytocin is one of the oldest and best characterised triggers on the shelf.
Analytical method development
Assay and mass spec work that needs a defined nonapeptide with a published formula and mass, plus a disulfide bond that behaves predictably when you reduce it.
Peptide chemistry teaching
The reference molecule for how peptide synthesis started. If you're showing somebody what a cyclised nonapeptide looks like in practice, this is the one with a Nobel attached to it.
Sold for laboratory research only. This is not guidance for personal use, and nothing here is a recommendation.
Oxytocin Peptide backstory
How it got here.
Before 1953 nobody had ever built a peptide hormone. People pulled them out of glands, ground them up, purified them down and then argued about what was actually in the bottle.
Du Vigneaud's lab went the other direction and assembled one, bond by bond, then showed the built version did what the natural version did. That's the moment peptide chemistry stopped being extraction and started being construction.
Every product on this website exists downstream of it. Merrifield's solid phase method, the one that turned peptide synthesis into a machine job, was still eleven years away.
Du Vigneaud did it in solution, the hard way, one coupling at a time. The Nobel committee handed him the 1955 prize in chemistry for work on sulphur compounds of biochemical importance, and specifically for the first synthesis of a polypeptide hormone.
Seventy odd years later the exact same nine residues come off a synthesiser in an afternoon.
- 1
1953, built not extracted
Du Vigneaud's lab assembles oxytocin in solution. First polypeptide hormone ever made from scratch instead of pulled out of an animal gland.
- 2
The title says octapeptide
The 1953 paper counts cystine as a single residue, so the founding paper of peptide synthesis undercounts its own molecule. Nine residues, eight in the headline.
- 3
1955, Stockholm
The Nobel Prize in Chemistry goes to du Vigneaud for the work. Merrifield's solid phase synthesis, the thing that made peptides routine, is still a decade out.
Buying Oxytocin Peptide in Canada
What ships, how fast, and the paperwork.
The hard part of buying research material is almost never the compound. It is the logistics. What leaves the building, how fast it moves, and what is in the box beside the vial. Here is ours, plainly.
It's a prescription drug here, and this isn't it
Oxytocin injection sits on Canada's Prescription Drug List with live DINs behind it. What ships from us is a research reagent for laboratory use. Not the approved medicine, not a stand in for it, and not sold for use in people or animals.
Schedule F is a dead term
If a vendor page tells you a compound is Schedule F, that page is at least a decade stale. Schedule F was replaced by the Prescription Drug List on 19 December 2013. Oxytocin sits on that list today.
Ships domestic
Stock sits in British Columbia and orders leave from there, so nothing sits at a border waiting on a customs officer's mood. Lyophilised powder in a sealed vial, 2mg or 5mg.
Stuff people ask about Oxytocin Peptide
If your question is not here, email us. Real human answers.
A nine amino acid peptide hormone, sequence CYIQNCPLG with a glycine amide on the end, closed into a ring by a disulfide bond between the first and sixth cysteines. Formula C43H66N12O12S2, molecular weight 1007.19, CAS 50-56-6. Your hypothalamus makes it and your posterior pituitary stores it. It's also the first peptide hormone anybody ever synthesised in a laboratory.
Two residues. That's the whole thing. Both are nonapeptides, both get pinched shut by the same Cys1 to Cys6 disulfide, and they only disagree at positions three and eight. Oxytocin runs isoleucine and leucine there, vasopressin runs phenylalanine and arginine. That similarity is exactly why the Pitocin label says the drug is prepared synthetically to avoid possible contamination with vasopressin.
Yes, and that makes it unusual for this catalogue. Health Canada lists marketed DINs 00497398 from Pfizer, 02139561 from Fresenius Kabi and 02550199 from Hikma, every one of them prescription. FDA approved Pitocin under NDA 018261 back in November 1980. The authorised use is labour and postpartum uterine control. The vial sold on this page is a research reagent, not that medicine.
No. We ran a full text search of the WADA Prohibited List and oxytocin doesn't appear anywhere on it, not in S2 and not in a subclause. That's genuinely uncommon around here, since gonadorelin, triptorelin and erythropoietin all get named explicitly. Absence from a prohibited list isn't permission for anything else though. It just means the list doesn't mention it.
Because cystine counted as one residue back then instead of two cysteines joined by a disulfide. Under that convention oxytocin has eight units. Under the modern one it has nine. Du Vigneaud used the old count in his title, then the field changed how it counted, and the number quietly moved underneath the founding paper of the whole discipline.
Lyophilised oxytocin powder in a sealed vial, either 2mg or 5mg, sold as a research chemical for laboratory use only. Not for human consumption, not for veterinary use, and not a substitute for the prescription product that carries a DIN. Stock sits in British Columbia and orders go out domestically, so nothing crosses a border to reach you.
Good pairing options with Oxytocin Peptide
What researchers stack alongside it.
Pairing is where research gets ahead of itself. These are the compounds researchers put in the same order as Oxytocin Peptide, which is a statement about ordering habits, not about evidence. Two things in one cart have not been studied together unless somebody studied them together.
Seven residues that shut a potassium channel called TREK-1. One laboratory, one paper, and a number so striking that the right response is to wait for somebody else to see it too.
A peptide preparation made from pig brain, used in clinics across half the world. A 2023 Cochrane review found no mortality benefit and a 2.39 relative risk of serious adverse events. We are leading with that on purpose.
Order Oxytocin Peptide right now
One last look before you decide.
Freeze-dried, COA on the page, ships cold
If you are researching Oxytocin Peptide and you want a source you do not have to second-guess, start with the paperwork on this page. For research use only.
Not for human consumption. Not approved by Health Canada or any other regulatory body.
Page last updated August 19, 2026
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