Peptides
Oxytocin
5mg
Cyclic nonapeptide. Social behaviour and receptor research.
98.39% purity · Supplier-reported analysis · Batch UKPL-9512 · View certificate
- Same-day dispatch before 3pm, Mon to Fri
- Add £44.01 more for free UK delivery
- Cold-chain shipping. Always. Dry-cold pack, Royal Mail Tracked 24
- Lost, damaged or wrong? Replaced free if you tell us within 48 hours.
- Research use only. For in-vitro laboratory research. Not for use in humans or animals, or in food, drugs or diagnostics. Not evaluated by the MHRA or FDA. The buyer is responsible for handling and regulatory compliance.
Bulk Pricing
Counted across your basket, any mix of products.
| Vials in basket | Discount | Per vial |
|---|---|---|
| 1 | None | £24.99 |
| 3-4 | 5% | £23.74 |
| 5-9 | 8% | £22.99 |
| 10-50 | 12% | £21.99 |
Bacteriostatic Water 10ml
Required to reconstitute lyophilised peptides.
What is Oxytocin?
Oxytocin is a cyclic nonapeptide, Cys-Tyr-Ile-Gln-Asn-Cys-Pro-Leu-Gly-NH₂, closed by a disulphide bridge between its two cysteines. It is one of the most heavily studied neuropeptides, with research on social behaviour, pair bonding, stress and receptor pharmacology.
Full description
In one-letter code it is CYIQNCPLG-NH₂. Its formula is C₄₃H₆₆N₁₂O₁₂S₂, its molecular weight 1007.19 g/mol and its CAS number 50-56-6. A disulphide bridge between cysteines 1 and 6 closes a twenty-atom ring, and the C-terminus is an amide.
Du Vigneaud, Ressler and Trippett (J Biol Chem, 1953) published the sequence and proposed structure. Du Vigneaud's group reported the first synthesis the same year (J Am Chem Soc, 1953), work recognised by the 1955 Nobel Prize in Chemistry. In the body it is made mainly in the paraventricular and supraoptic nuclei of the hypothalamus and released from the posterior pituitary. Oxytocin is also a licensed prescription medicine. The lyophilised powder sold here is a research reagent, not a pharmaceutical product. Each Oxytocin 5mg vial holds white lyophilised powder.
Oxytocin Research Applications
- Receptor pharmacology: oxytocin is the reference agonist at OXTR, a class A GPCR coupled mainly through Gq to phospholipase C (Gimpl and Fahrenholz, Physiol Rev, 2001).
- Binding assays: the high-affinity receptor state needs both Mg2+ and cholesterol, which matters for buffer and membrane preparation (Gimpl and Fahrenholz, 2001).
- Structural biology: Waltenspühl and colleagues (Sci Adv, 2020) solved the crystal structure of the human oxytocin receptor bound to retosiban, a non-peptide antagonist.
- Pair bonding: prairie vole work links oxytocin signalling to partner preference (Insel and Hulihan, Behav Neurosci, 1995; Donaldson and Young, Science, 2008).
- Stress research: Grinevich and Neumann (Mol Psychiatry, 2021) review its anti-stress effects and their translation to psychiatry.
Study details
The oxytocin system has drawn nearly 25,000 publications since 1930 (Jurek and Neumann, Physiol Rev, 2018). Typical in-vitro work uses binding and calcium mobilisation assays in OXTR-transfected cell lines. Other models cover myometrial contraction and mammary myoepithelial cells. The human social-cognition strand is contested. A well-known study on trust (Kosfeld et al., Nature, 2005) has not replicated reliably (Nave et al., Perspect Psychol Sci, 2015).
Oxytocin vs Vasopressin
Oxytocin and arginine vasopressin are the two cyclic nonapeptides of the posterior pituitary. They differ at two positions. Vasopressin (CYFQNCPRG-NH₂) has phenylalanine at 3 and arginine at 8, where oxytocin has isoleucine and leucine. Oxytocin acts mainly at the oxytocin receptor (OXTR). Vasopressin acts at the V1a, V1b and V2 receptors, with some cross-binding at higher concentrations. So the two are not interchangeable tools. Residues 3 and 8 are the classic handles for analogue design.
Research Overview
OXTR is expressed in uterine smooth muscle, mammary myoepithelial cells and many brain regions. The receptor system was catalogued by Gimpl and Fahrenholz (Physiol Rev, 2001) and updated by Jurek and Neumann (Physiol Rev, 2018).
The popular idea of oxytocin as a trust or love hormone runs ahead of the evidence. Nave and colleagues (Perspect Psychol Sci, 2015) concluded that the human data do not give convergent evidence that oxytocin reliably causes trust. The animal social behaviour literature is much stronger than the human literature. That gap is part of what keeps oxytocin an active research subject.
Product Specifications
- Molecular Formula
- C₄₃H₆₆N₁₂O₁₂S₂
- Molecular Weight
- 1007.19 g/mol
- CAS Number
- 50-56-6
- Sequence
- Cys-Tyr-Ile-Gln-Asn-Cys-Pro-Leu-Gly-NH₂, disulphide bridge Cys1-Cys6
- Purity
- 98.39%
- Batch
- UKPL-9512
- Storage
- -20°C lyophilised, 2-8°C reconstituted
- Appearance
- White lyophilised powder
- Form
- Lyophilised powder
Certificate of Analysis
Supplier-reported analysis. Independent third-party verification pending.
- Batch
- UKPL-9512
- Purity
- 98.39%
- Specification
- ≥98.0%
- Method
- RP-HPLC
- Tested
- Sep 2026
Need the certificate for an earlier batch? Request an older CoA
Storage and Reconstitution
Move vials to the freezer on arrival and keep them dark and dry. In solution oxytocin degrades by deamidation and by disulphide exchange. Disulphide scrambling forms dimers and related species that show as new RP-HPLC peaks, and repeated freeze-thaw speeds this up. Keep vials sealed with little headspace and aliquot the solution instead of reopening one stock.
Vials are sold on their own, without bacteriostatic water for mixing or other supplies.
How to reconstitute and handle
Let the vial reach room temperature. Wipe the stoppers of the peptide vial and the bacteriostatic water vial with an alcohol swab. Add the water slowly down the inside wall of the vial, not onto the powder. Swirl gently until it dissolves, and do not shake or vortex. The solution should be clear and colourless. Label the vial with the date.
- Work away from strong light, keep stopper-open time short, and re-seal promptly after each draw.
- Prepare single-use aliquots at reconstitution and label each with the date.
For the full method, see the peptide reconstitution guide and the reconstitution calculator.
Research References
- The sequence of amino acids in oxytocin, with a proposal for the structure of oxytocin (du Vigneaud, Ressler and Trippett, J Biol Chem, 1953)
- The oxytocin receptor system: structure, function, and regulation (Gimpl and Fahrenholz, Physiol Rev, 2001)
- Oxytocin, vasopressin, and the neurogenetics of sociality (Donaldson and Young, Science, 2008)
- Crystal structure of the human oxytocin receptor (Waltenspühl et al., Sci Adv, 2020)
Published research on Oxytocin is indexed on PubMed.
Oxytocin Price (UK)
Oxytocin 5mg is for sale at £24.99 per vial, supplied from stock in the UK with a published supplier batch certificate. UK delivery is £4.50 by Royal Mail Tracked 24, free over £69.
| Vial | Price | Cost per mg | Availability |
|---|---|---|---|
| Oxytocin 5mgThis page | £24.99 | £5.00 | In stock |
Prices are in GBP per vial and match the basket. See the FAQ for delivery and payment options, and quality & testing for how each batch is checked.
Frequently Asked Questions
How does oxytocin work at the molecular level?
It binds the oxytocin receptor (OXTR), a class A G-protein-coupled receptor. OXTR signals through Gq/11 to phospholipase C and calcium mobilisation (Gimpl and Fahrenholz, Physiol Rev, 2001; Jurek and Neumann, Physiol Rev, 2018). The receptor's high-affinity state needs Mg2+ and cholesterol. Waltenspühl and colleagues (Sci Adv, 2020) solved the human receptor's crystal structure with the antagonist retosiban.
Is oxytocin a licensed medicine?
Yes, as a finished pharmaceutical. Oxytocin medicines are licensed, and in the UK they are prescription-only. That status covers those pharmaceutical products, not this material. The lyophilised oxytocin sold here is a reference material for in-vitro research and is not supplied for human or veterinary use.
What does the pair bonding research show?
In prairie voles, oxytocin facilitated partner preference formation in females (Insel and Hulihan, Behav Neurosci, 1995). Insel and Young (Nat Rev Neurosci, 2001) reviewed the neurobiology of attachment. Donaldson and Young (Science, 2008) reviewed the receptor genetics. These are animal findings. Their extension to human attachment is an inference.
Is oxytocin legal to buy in the UK for research?
Yes, as a research reagent only. Injectable oxytocin medicines are prescription-only in the UK, so it cannot be sold or supplied for human use. UK Peptide Lab sells the lyophilised peptide only as a reference material for in-vitro research. Buyers must be 18 or over and confirm research-only use at checkout.
How should oxytocin be handled in the laboratory?
Store sealed vials at -20°C away from light and moisture. Reconstitute by running bacteriostatic water slowly down the vial wall and swirling gently until clear; do not shake. Minimise headspace and keep aliquots single-use, because disulphide exchange forms dimers in solution. Keep the solution at 2-8°C and use it within 4 weeks.
Where can I buy Oxytocin in the UK for research?
UK Peptide Lab sells Oxytocin 5mg vials of lyophilised powder from UK stock. Orders placed before 3pm on a working day are dispatched the same day by Royal Mail Tracked, and UK delivery is free over £69. It is sold for in-vitro research only, to buyers aged 18 or over.
What is oxytocin peptide used for in research?
Receptor, structural and behavioural research. It is the reference agonist at OXTR (Gimpl and Fahrenholz, Physiol Rev, 2001) and a reference ligand in receptor structure work. Animal models use it in pair bonding (Insel and Hulihan, 1995) and stress research (Grinevich and Neumann, 2021).
Is your Oxytocin third-party tested?
Not yet. The published certificate for batch UKPL-9512 is the supplier's analysis, reporting 98.39% purity by RP-HPLC and 5.11mg measured content against the 5mg label. Independent third-party testing of this batch is in progress, and that report will be published when complete. Every vial label carries the batch number.
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