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Oxytocin / Studies
Natural peptide · 9 amino acids · 1,007.2 Da

Oxytocin studies and research data

PepBank has 1,640 oxytocin studies with results. 996 of them gave oxytocin, with 3,492 results, grouped by what the studies measured. In each group, results from studies in people come first. Data as of 2026-10-30.

Searches 3,492 results and 30,376 papers. Newer studies from Europe PMC

Results in people
2,688
77% of 3,492 results
Results in animals
544
16% of 3,492 results
Results in lab cells
258
7% of 3,492 results
From computer models
2
under 1% of 3,492 results
The molecule

Oxytocin identity

Identifiers, parent molecule, targets and development stage, from curated data.

Oxytocin is a nine-residue peptide hormone (CYIQNCPLG-NH2) with a Cys1-Cys6 disulfide bond and a C-terminal glycinamide, processed from the OXT precursor (UniProt P01178, residues 20-28). It is an agonist at the oxytocin receptor; GSRS also records agonist activity at the vasopressin V1a receptor and weak agonist activity at V1b. Synthetic oxytocin injection (Pitocin, NDA 018261, and other products) is FDA-approved for medically indicated induction or stimulation of labor and for postpartum uterine contraction and bleeding control. Use in Prader-Willi syndrome has US and EU orphan designations but no approval.

Kind
Natural peptide · 9 residues
Identifiers
UniProtP01178 (opens in a new tab)ChEMBLCHEMBL395429 (opens in a new tab)PubChem CID439302 (opens in a new tab)UNII1JQS135EYN (opens in a new tab)DrugBankDB00107 (opens in a new tab)CAS50-56-6PDB7OFG (opens in a new tab)7OTD (opens in a new tab)7QVM (opens in a new tab)7RYC (opens in a new tab)KEGGD00089 (opens in a new tab)IUPHAR2174 (opens in a new tab)
Development
Approved in the US (Pitocin, 1980)Multiple (Par Health / PH Health for Pitocin; generic manufacturers)Approved for obstetric use. Other uses (for example Prader-Willi syndrome) are investigational. Source (opens in a new tab)

Targets

Molecular targets with action and evidence source
TargetActionEvidence
Oxytocin receptorOXTRP30559 (opens in a new tab)Agonistapproved-drug labelSource (opens in a new tab)
Vasopressin V1a receptorAVPR1AP37288 (opens in a new tab)AgonistproposedSource (opens in a new tab)
Vasopressin V1b receptorAVPR1BP47901 (opens in a new tab)Weak agonistproposedSource (opens in a new tab)

Sequence and structure

Residues, differences from the parent, calculated properties and 3D structure. Source values and calculated values are shown separately.

Sequence

9 amino acids · 2 modifications · 1 disulfide bond

H-
Residues 1 to 9:
CYIQNCPLG
  • HydrophobicA V I L M
  • AromaticF W Y
  • PolarS T N Q
  • SpecialC G P
  • Modified residue
  • Disulfide partner

Modifications

Gly9-NH2
C-terminal amide
C-terminal glycinamide (UniProt 'Glycine amide' at 28; GSRS).
Cys1–Cys6
Disulfide bond
Intramolecular disulfide Cys1-Cys6 (UniProt P01178 20-25; GSRS; ChEMBL HELM).

Properties

From identity sources

Formula
C43H66N12O12S2
Molecular weight
1,007.2 g/mol
Monoisotopic mass
1,006.4365 Da

Calculated from the sequence

Average mass
1,007.19 Da
Sum of ExPASy residue masses + water + C-amide, 1 disulfide · ExPASy Compute pI/Mw; FindMod
Monoisotopic mass
1,006.4365 Da
Sum of ExPASy residue masses + water + C-amide, 1 disulfide · ExPASy FindMod
Isoelectric point (pI)
9.35
pH of zero net charge, EMBOSS pKa set · EMBOSS iep, Epk.dat
Net charge at pH 7.4
0.94
Henderson-Hasselbalch, EMBOSS pKa set · EMBOSS iep, Epk.dat
GRAVY (hydropathy)
0.333
Mean Kyte-Doolittle hydropathy · Kyte and Doolittle 1982
Positive: hydrophobic on average.
Extinction coefficient, 280 nm (Cys reduced)
1,490 M⁻¹ cm⁻¹
5500 x Trp + 1490 x Tyr · Pace et al. 1995 (ExPASy ProtParam)
No Trp: ExPASy reports more than 10 % error without Trp.
Extinction coefficient, 280 nm (all Cys as cystines)
1,615 M⁻¹ cm⁻¹
5500 x Trp + 1490 x Tyr + 125 x cystine · Pace et al. 1995 (ExPASy ProtParam)
Instability index
27.09
Dipeptide instability weights (DIWV) · Guruprasad et al. 1990
40 or below: classed as stable (ExPASy).
Aliphatic index
86.7
Mole % A + 2.9 V + 3.9 (I + L) · Ikai 1980
Boman index
−0.11 kcal/mol
Mean solubility value (negated) · Boman 2003
2.48 or below: lower protein-binding potential (Boman).
Hydrophobic moment (μH)
Not calculated
The sequence is too short for this method.
pI with each pKa set
EMBOSS 9.35Bjellqvist (ExPASy) 8.75IPC peptide 9.82IPC protein 9.97
  • Defined and validated for proteins; use with care for short peptides.
  • Assumes an ideal alpha helix. Many short peptides are not helical.

@pepdb/chem 0.2.0 · EMBOSS pKa set · ExPASy residue masses

Net charge by pH

pI 9.35 · Net charge at pH 7.4: 0.94

Point or use arrow keys

Net charge of Oxytocin from pH 0 to 14 (EMBOSS pKa set). Isoelectric point 9.35. Net charge at pH 7.4: 0.94.−1−0.50+0.5+102468101214pHNet chargepH 7.4pI 9.35

Henderson-Hasselbalch, EMBOSS pKa set, C-amide, 1 disulfide. Calculated, not measured.

Show as table
pHNet charge
01.00
11.00
21.00
31.00
41.00
51.00
61.00
70.97
80.79
90.21
10−0.40
11−0.88
12−0.99
13−1.00
14−1.00

Composition

  • Hydrophobic22% (2)
  • Aromatic11% (1)
  • Polar22% (2)
  • Special44% (4)

9 residues. Each residue counts in one class; F and W count as aromatic.

A Ala0 · 0%
I Ile1 · 11%
L Leu1 · 11%
M Met0 · 0%
V Val0 · 0%
F Phe0 · 0%
W Trp0 · 0%
Y Tyr1 · 11%
H His0 · 0%
K Lys0 · 0%
R Arg0 · 0%
D Asp0 · 0%
E Glu0 · 0%
N Asn1 · 11%
Q Gln1 · 11%
S Ser0 · 0%
T Thr0 · 0%
C Cys2 · 22%
G Gly1 · 11%
P Pro1 · 11%

3D structure

ExperimentalPDB 7OFG

Loads the 3D viewer (3Dmol.js, about 150 KB) and the model file from RCSB PDB.

RCSB Protein Data Bank · CC0 1.0

2D structure

Draws the structure in your browser with RDKit (about 2.3 MB, loaded once).

SMILES fromPubChem CID 439302(opens in a new tab)

CC[C@H](C)[C@H]1C(=O)N[C@H](C(=O)N[C@H](C(=O)N[C@@H](CSSC[C@@H](C(=O)N[C@H](C(=O)N1)CC2=CC=C(C=C2)O)N)C(=O)N3CCC[C@H]3C(=O)N[C@@H](CC(C)C)C(=O)NCC(=O)N)CC(=O)N)CCC(=O)N
Results by area

What the studies measured

People first in each area, then animals, then lab cells. Counts are exact and come from studies that gave the peptide.

Trials and papers
Status and safety
Data