Oxytocin

Overview

Oxytocin is a nine-amino acid peptide hormone (Cys-Tyr-Ile-Gln-Asn-Cys-Pro-Leu-Gly-NH2, with a disulfide bridge between Cys1 and Cys6) produced in the hypothalamic paraventricular and supraoptic nuclei. The synthetic form (Pitocin) is FDA-approved as IV/IM injection for labor induction/augmentation and postpartum hemorrhage control. Intranasal oxytocin is NOT FDA-approved and is used off-label or in research settings for social/behavioral indications, where evidence is mixed.

Mechanism of Action

Oxytocin binds oxytocin receptors (OXTR, a Gq-coupled GPCR) on uterine myometrium (triggering contractions) and breast myoepithelial cells (milk let-down). Centrally, OXTR is expressed in amygdala, hypothalamus, nucleus accumbens, and other limbic regions where it modulates social cognition, pair bonding, and stress reactivity. At high IV doses, oxytocin has weak antidiuretic (ADH-like) activity at V2 receptors, which can cause water retention and hyponatremia.

Research Summary

Pitocin has decades of obstetric use under its FDA label. Intranasal oxytocin has been studied in dozens of RCTs across autism, social anxiety, PTSD, and schizophrenia. Evidence is MIXED and frequently negative for larger/more rigorous trials. Sikich et al. 2021 (NEJM, SOARS-B, PMID 34644471) — the largest placebo-controlled RCT (N=290) of intranasal oxytocin for autism — found no significant benefit over placebo on social or cognitive functioning over 24 weeks. Ooi et al. 2017 meta-analysis (PMID 27574858) found no significant overall effect of oxytocin on social cognition or repetitive behaviors in ASD. Leng & Ludwig 2016 'Intranasal Oxytocin: Myths and Delusions' (Biological Psychiatry, PMID 26049207) estimate <0.005% of intranasal dose reaches CSF, questioning the pharmacologic basis for reported behavioral effects. Marketing of intranasal oxytocin as a 'love/bonding' compound is not supported by the strongest clinical evidence. Pitocin FDA label: https://www.accessdata.fda.gov/drugsatfda_docs/label/2014/018261s031lbl.pdf

Vendors selling Oxytocin

Scored vendors carrying Oxytocin, ranked by trust grade. Grades are computed from indexed Certificates of Analysis. Full $/mg pricing is on the comparison page.

Prescribers who offer Oxytocin

27 prescribers in our directory work with Oxytocin, each confirmed from their own website. Peptides like Oxytocin require a prescription from a licensed provider — telehealth options are available.

Reported Side Effects

• IV (labor doses): uterine hyperstimulation, fetal distress, water intoxication / hyponatremia (ADH-like effect at high doses), hypotension, nausea
• Intranasal (research doses): generally well tolerated — mild nasal irritation, headache, occasional GI upset
• Rare: hypersensitivity reactions

Compare Oxytocin with Others

Research References

• Intranasal Oxytocin in Children and Adolescents with Autism Spectrum Disorder (SOARS-B; Sikich et al., NEJM) (2021)
• Intranasal Oxytocin: Myths and Delusions (Leng & Ludwig) (2016)
• Oxytocin and Autism Spectrum Disorders: A Systematic Review and Meta-Analysis of Randomized Controlled Trials (Ooi et al.) (2017)
• Pitocin (oxytocin injection, USP) FDA Prescribing Information (2014)

Frequently asked questions

Has Oxytocin been independently lab-tested?

Disclosed Labs has collected 31 Certificates of Analysis (COA) for Oxytocin from 9 independent testing labs. 16 vendors have submitted material for testing. Products average 99.0% tested purity across the corpus. Full testing data is available at https://www.disclosedlabs.com/peptides/oxytocin/testing.

What is the average purity of Oxytocin on the market?

Based on 31 COAs analyzed by Disclosed Labs, Oxytocin products average 99.0% (±1.0%) tested purity. Individual vendor results vary; see per-vendor COA data at https://www.disclosedlabs.com/peptides/oxytocin/coas.

Which labs have tested Oxytocin?

Independent labs that have tested Oxytocin include: ILS Labs (Grade A). Full lab credibility grades and profiles are at https://www.disclosedlabs.com/labs.

Where can researchers source Oxytocin?

8 vendors with Disclosed Labs trust grades currently list Oxytocin, including Real Peptides, Peptide Supply Co., BioLongevity Labs. Compare live prices and lab-verified COAs at https://www.disclosedlabs.com/prices/oxytocin.

Which prescribers offer Oxytocin with a prescription?

27 prescribers in the Disclosed Labs directory work with Oxytocin, each confirmed from their own website, with telehealth options available. Oxytocin requires a prescription from a licensed provider. Browse them at https://www.disclosedlabs.com/prescribers?peptide=Oxytocin.

How does Oxytocin work?

Oxytocin binds oxytocin receptors (OXTR, a Gq-coupled GPCR) on uterine myometrium (triggering contractions) and breast myoepithelial cells (milk let-down). Centrally, OXTR is expressed in amygdala, hypothalamus, nucleus accumbens, and other limbic regions where it modulates social cognition, pair bonding, and stress reactivity. At high IV doses, oxytocin has weak antidiuretic (ADH-like) activity at V2 receptors, which can cause water retention and hyponatremia.

What does the research say about Oxytocin?

Pitocin has decades of obstetric use under its FDA label. Intranasal oxytocin has been studied in dozens of RCTs across autism, social anxiety, PTSD, and schizophrenia. Evidence is MIXED and frequently negative for larger/more rigorous trials. Sikich et al. 2021 (NEJM, SOARS-B, PMID 34644471) — the largest placebo-controlled RCT (N=290) of intranasal oxytocin for autism — found no significant benefit over placebo on social or cognitive functioning over 24 weeks. Ooi et al. 2017 meta-analysis (PMID 27574858) found no significant overall effect of oxytocin on social cognition or repetitive behaviors in ASD. Leng & Ludwig 2016 'Intranasal Oxytocin: Myths and Delusions' (Biological Psychiatry, PMID 26049207) estimate <0.005% of intranasal dose reaches CSF, questioning the pharmacologic basis for reported behavioral effects. Marketing of intranasal oxytocin as a 'love/bonding' compound is not supported by the strongest clinical evidence. Pitocin FDA label: https://www.accessdata.fda.gov/drugsatfda_docs/label/2014/018261s031lbl.pdf