No. 046 · Hormones & Drive · Hormonal Peptide
Oxytocin
Also known as: PitocinSyntocinon
- FDA approved
- WADA — not listed
- Nonpolar 4
- Polar 5
Each dot is a residue placed around the ring from N- to C-terminus; its distance from the centre reflects its chemistry.
Evidence
- D In vitro
- C Animal
- B Human pilot
- A RCT
- S Approved
TIER S — Approved by the FDA or EMA for at least one indication.
FDA-approved injectable drug (Pitocin and generics) used in obstetrics. Intranasal use for social or psychiatric effects is investigational.
Tiers rate the strength of published evidence — not effectiveness, safety, or a recommendation.
At a glance
- Residues
- 9 amino acids, N→C
- Molecular weight
- 1,007.2 Da
- Formula
- C43H66N12O12S2
- Discovered
- 1953 Vincent du Vigneaud determined its structure and synthesized it, the first polypeptide hormone ever synthesized (Nobel Prize in Chemistry, 1955).
- Routes studied
- Intranasal, Subcutaneous, Intravenous Routes used in published research
- FDA
- Approved Pitocin Approved to induce or strengthen uterine contractions and to control bleeding after delivery.
- WADA
- Not on the Prohibited List
Sequence
Note Disulfide bridge between Cys1 and Cys6; C-terminal glycinamide.
Overview
The endogenous "bonding hormone" produced in the hypothalamus, used therapeutically for labor induction and explored for social cognition, anxiety, and pair-bonding enhancement.
Research status FDA-approved (Pitocin) for labor induction; extensive published research on intranasal social cognition effects
Mechanism
Oxytocin is a nine-amino-acid neuropeptide synthesized in hypothalamic paraventricular and supraoptic nuclei that binds the oxytocin receptor (OXTR), a Gq-coupled GPCR. In the brain, it modulates amygdala reactivity and promotes social approach behavior. Peripherally, it stimulates uterine smooth muscle contraction and mammary gland myoepithelial cell contraction for milk letdown.
Effects reported in research
Reported outcomes, not promises. Some come from controlled human trials; others may be from smaller or preclinical studies — check the studies below.
- Enhanced social bonding and trust
- Reduced social anxiety
- Improved emotional recognition
- Supported lactation and uterine contractions (clinical use)
Safety & unknowns
FDA-approved (Pitocin) for labor induction with well-established safety profile. Intranasal use for social/cognitive effects is off-label. Side effects: headache, nasal irritation (intranasal), water retention at high doses. Avoid in pregnancy unless for labor induction under medical supervision.
Unknowns. Trial safety data apply to the populations, formulations and conditions studied.
Informational only — not medical advice. peptidemeta publishes no dosing, protocols, or sourcing. Talk to a qualified clinician about any treatment decision.
Studies [1]
- Clinical trial 2011
Oxytocin modulates amygdala, insula, and inferior frontal gyrus responses to infant crying: a randomized controlled trial
Randomized controlled fMRI study in which intranasal oxytocin reduced amygdala activation and increased insula and inferior frontal gyrus responses to infant crying.
Status sources
Sources behind the tier, regulatory status, sequence and dates on this page.
- Drugs@FDA — NDA 018261 (Pitocin) accessdata.fda.gov
- DailyMed — Pitocin (oxytocin injection) label dailymed.nlm.nih.gov
- PubChem CID 439302 (oxytocin) pubchem.ncbi.nlm.nih.gov
- Nobel Prize in Chemistry 1955 — du Vigneaud nobelprize.org
- WADA 2026 Prohibited List (oxytocin not named) wada-ama.org
Cite this entry
peptidemeta. (2026). Oxytocin. In peptidemeta: The peptide library, ranked by evidence. Retrieved November 8, 2026, from https://peptidemeta.com/p/oxytocin/
@misc{peptidemeta-oxytocin,
title = {Oxytocin},
author = {{peptidemeta}},
year = {2026},
howpublished = {\url{https://peptidemeta.com/p/oxytocin/}},
note = {Accessed 2026-11-08}
} Accessed date reflects when you opened this page. Cite primary studies for scientific claims.