reptides / oxytocin

oxytocin

Oxytocin causes uterine contractions and is used in obstetric care to induce labor and control bleeding after delivery. Nasal sprays have also been studied for social behavior, anxiety and sexual function, with inconsistent results. Large autism and trust studies found no meaningful benefit on their main outcomes.

Endogenous cyclic nonapeptide and oxytocin-receptor agonist

  • Current Pitocin is a 10 units/mL synthetic oxytocin injection.
  • The label excludes elective induction and requires hospital IV monitoring for labor induction or stimulation.
  • The former US Syntocinon nasal approval was withdrawn in 1997 after commercial discontinuation.
  • A 290-person youth autism trial was null on its primary social outcome.
  • A 2026 registered trust replication and 532-person pooled analysis found no meaningful trust-game effect.
  • Controlled sexual-function findings are mixed and do not establish a reliable libido or orgasm treatment.
Which oxytocin? What is it? What is approved? Why hospital only? Autism evidence? Trust and bonding? Social anxiety? PTSD prevention? Sexual function? Does nasal reach brain? Nasal safety? US nasal status? Why the Nobel? Why B tier?

How do injectable and nasal oxytocin differ?

Injectable oxytocin is an approved obstetric medicine. Nasal formulations have been studied for social behavior, psychiatric symptoms and sexual function, but the cited FDA records contain no current U.S. approval for those uses.

Oxytocin products and uses
UseProduct and settingOutcome measuredWhat the evidence says
Labor induction or augmentationPitocin IV infusion in a hospitalUterine response plus maternal and fetal safetyFDA-labeled for medically indicated use with continuous monitoring
Postpartum bleeding controlPitocin IV infusion or indicated IM use in obstetric careSustained uterine contraction and bleeding controlFDA-labeled acute use
Behavioral or psychiatric researchStudy-specific intranasal sprayDiagnosis-specific symptom scale or laboratory taskNo current US approved nasal product or behavioral indication identified
Compounded nasal usePharmacy-specific formulation and deviceThe prescribed target plus product qualityNot FDA-approved; trial results do not prove equivalence to that preparation

Units, exposure, and device are not interchangeable across rows.

Pitocin label · indications, route, monitoring, harms

Current US prescribing information

DailyMed, US National Library of Medicine, revised March 2026

The label identifies Pitocin as synthetic oxytocin 10 units/mL for intravenous infusion or intramuscular injection. It covers medically indicated initiation or improvement of uterine contractions, selected abortion management, third-stage uterine contraction, and control of postpartum bleeding or hemorrhage. It says the drug is not indicated for elective induction. Induction or stimulation requires intravenous infusion in a hospital with continuous observation and fetal monitoring.

  • The label reports a plasma half-life of about 1 to 6 minutes.
  • Excess exposure can cause uterine hypertonicity, tetanic contraction, rupture, fetal hypoxia, and death.
  • Its antidiuretic action can cause severe water intoxication with convulsions or coma during prolonged high-dose infusion.
Participants / model
Pregnant and postpartum patients in monitored obstetric care
Treatment
Oxytocin injection, 10 units/mL; intravenous infusion for induction or stimulation and intravenous infusion or intramuscular injection in specified postpartum use
Follow-up
Acute, clinician-controlled obstetric administration
Study design
FDA-regulated product label

A product label defines approved use and warnings. It does not validate intranasal behavioral or sexual uses.

Read the original source
Orange Book 2026 · nasal product discontinued

Current FDA drug-product directory

US Food and Drug Administration, Approved Drug Products with Therapeutic Equivalence Evaluations, 46th edition, 2026

The 2026 discontinued-products list includes Syntocinon oxytocin nasal solution, 40 USP units/mL, NDA 012285. The same list separately identifies discontinued injectable oxytocin products. It does not show a currently marketed US nasal oxytocin approval.

Participants / model
US approved-drug product records
Treatment
Syntocinon nasal solution 40 USP units/mL
Follow-up
Directory status as published in 2026
Study design
FDA regulatory directory

Discontinued listing describes market status. The reason for withdrawal comes from the 1997 Federal Register notice.

Read the original source
FDA compounding Q&A · what approval does not cover

Current FDA regulatory guidance page

US Food and Drug Administration, updated 2026

FDA states that compounded drugs are not FDA-approved and that the agency does not verify their safety, effectiveness, or quality before marketing. Compounding may meet an individual need, but facility, formulation, concentration, and device still matter.

Participants / model
US compounded human drugs
Treatment
General compounding framework
Study design
FDA public guidance

This source does not decide whether a particular prescription or preparation satisfies every applicable compounding rule.

Read the original source

What is oxytocin?

Oxytocin is a cyclic nine-amino-acid hormone. Its receptor raises calcium inside uterine muscle cells, causing contractions. Nasal studies examine effects on brain activity and behavior, but clinical trials have produced inconsistent results.

  • Identity: CYIQNCPLG, with a disulfide bridge between cysteines 1 and 6 and an amidated terminus.
  • Peripheral action: OXTR activation in the pregnant uterus increases intracellular calcium and contraction. Receptor density and uterine sensitivity rise around labor.
  • Central research: nasal studies probe social attention, threat processing, learning, and other circuits. A neural or laboratory-task effect is not automatically a useful treatment effect.
FDA SRS · molecular identity

Official substance identity record

US Food and Drug Administration, Substance Registration System

FDA records oxytocin under UNII 1JQS135EYN as the cyclic nine-residue peptide CYIQNCPLG with a disulfide link between cysteines 1 and 6 and an amidated glycine terminus.

Participants / model
Not applicable
Treatment
Substance identity only
Follow-up
Not applicable
Study design
Regulatory molecular registry

Identity does not establish a clinical effect for any route or indication.

Read the original source
Pitocin label · indications, route, monitoring, harms

Current US prescribing information

DailyMed, US National Library of Medicine, revised March 2026

The label identifies Pitocin as synthetic oxytocin 10 units/mL for intravenous infusion or intramuscular injection. It covers medically indicated initiation or improvement of uterine contractions, selected abortion management, third-stage uterine contraction, and control of postpartum bleeding or hemorrhage. It says the drug is not indicated for elective induction. Induction or stimulation requires intravenous infusion in a hospital with continuous observation and fetal monitoring.

  • The label reports a plasma half-life of about 1 to 6 minutes.
  • Excess exposure can cause uterine hypertonicity, tetanic contraction, rupture, fetal hypoxia, and death.
  • Its antidiuretic action can cause severe water intoxication with convulsions or coma during prolonged high-dose infusion.
Participants / model
Pregnant and postpartum patients in monitored obstetric care
Treatment
Oxytocin injection, 10 units/mL; intravenous infusion for induction or stimulation and intravenous infusion or intramuscular injection in specified postpartum use
Follow-up
Acute, clinician-controlled obstetric administration
Study design
FDA-regulated product label

A product label defines approved use and warnings. It does not validate intranasal behavioral or sexual uses.

Read the original source
Methods review · route, device, dose, timing, replication

Translational methods review

Quintana DS et al. Molecular Psychiatry. 2021

The review finds converging human and animal evidence that intranasal delivery can produce functionally relevant central effects, while emphasizing unresolved route mechanisms and the need to account for device, dose, timing, preregistration, statistical power, reproducibility, and sex. It does not support treating one CSF timing estimate as a universal nasal half-life.

Participants / model
Human and animal intranasal oxytocin literature
Treatment
Intranasal oxytocin across formulations, devices, and experimental protocols
Follow-up
Literature through 2020
Study design
Narrative translational methods review

A methods review supports interpretation of route and measurement. It is not proof of efficacy for any diagnosis.

Read the original source

What is Pitocin approved for?

The Pitocin label covers the obstetric uses listed below. It excludes elective labor induction without a medical indication and does not approve social, psychiatric or sexual uses.

  • Initiation of labor when maternal or fetal circumstances make induction medically indicated.
  • Stimulation or reinforcement of labor in selected uterine inertia.
  • Adjunctive management of incomplete or inevitable abortion.
  • Uterine contraction during the third stage of labor and control of postpartum bleeding or hemorrhage.

The label says no elective induction

Pitocin's label excludes labor induction without a medical indication.

Pitocin label · indications, route, monitoring, harms

Current US prescribing information

DailyMed, US National Library of Medicine, revised March 2026

The label identifies Pitocin as synthetic oxytocin 10 units/mL for intravenous infusion or intramuscular injection. It covers medically indicated initiation or improvement of uterine contractions, selected abortion management, third-stage uterine contraction, and control of postpartum bleeding or hemorrhage. It says the drug is not indicated for elective induction. Induction or stimulation requires intravenous infusion in a hospital with continuous observation and fetal monitoring.

  • The label reports a plasma half-life of about 1 to 6 minutes.
  • Excess exposure can cause uterine hypertonicity, tetanic contraction, rupture, fetal hypoxia, and death.
  • Its antidiuretic action can cause severe water intoxication with convulsions or coma during prolonged high-dose infusion.
Participants / model
Pregnant and postpartum patients in monitored obstetric care
Treatment
Oxytocin injection, 10 units/mL; intravenous infusion for induction or stimulation and intravenous infusion or intramuscular injection in specified postpartum use
Follow-up
Acute, clinician-controlled obstetric administration
Study design
FDA-regulated product label

A product label defines approved use and warnings. It does not validate intranasal behavioral or sexual uses.

Read the original source

Why is labor use a monitored hospital intervention?

The desired uterine effect can overshoot. The label requires IV infusion with continuous trained observation and electronic fetal monitoring for induction or stimulation because excessive frequency, strength, or duration of contractions can compromise both patient and fetus.

  • Uterine and delivery harms: hypertonicity, spasm, tetanic contraction, rupture, cervical or vaginal laceration, and postpartum hemorrhage.
  • Fetal and neonatal harms: altered fetal heart rate, hypoxia, hypercapnia, brain injury, perinatal hepatic necrosis, or death can follow uteroplacental hypoperfusion.
  • Fluid risk: oxytocin has intrinsic antidiuretic activity. Prolonged high exposure with fluid intake can cause water intoxication, seizures, coma, or death.
  • Interaction context: the label reports severe hypertension when oxytocin followed prophylactic vasoconstrictor use around caudal-block anesthesia; anesthetic and fluid plans therefore belong to the obstetric team.

Major contraindications include situations where vaginal delivery is contraindicated, major cephalopelvic disproportion, an undeliverable fetal position, fetal distress when delivery is not imminent, hyperactive or hypertonic uterus, and failed adequate uterine response.

Pitocin label · indications, route, monitoring, harms

Current US prescribing information

DailyMed, US National Library of Medicine, revised March 2026

The label identifies Pitocin as synthetic oxytocin 10 units/mL for intravenous infusion or intramuscular injection. It covers medically indicated initiation or improvement of uterine contractions, selected abortion management, third-stage uterine contraction, and control of postpartum bleeding or hemorrhage. It says the drug is not indicated for elective induction. Induction or stimulation requires intravenous infusion in a hospital with continuous observation and fetal monitoring.

  • The label reports a plasma half-life of about 1 to 6 minutes.
  • Excess exposure can cause uterine hypertonicity, tetanic contraction, rupture, fetal hypoxia, and death.
  • Its antidiuretic action can cause severe water intoxication with convulsions or coma during prolonged high-dose infusion.
Participants / model
Pregnant and postpartum patients in monitored obstetric care
Treatment
Oxytocin injection, 10 units/mL; intravenous infusion for induction or stimulation and intravenous infusion or intramuscular injection in specified postpartum use
Follow-up
Acute, clinician-controlled obstetric administration
Study design
FDA-regulated product label

A product label defines approved use and warnings. It does not validate intranasal behavioral or sexual uses.

Read the original source

Does intranasal oxytocin improve autism symptoms?

The largest youth trial found no benefit on its primary social outcome. Smaller studies reported signals, including a Chinese pilot that paired oxytocin with structured positive interaction, but those results have not established a broadly effective autism treatment.

Intranasal oxytocin trials in autism
StudyPopulation and productPrimary resultWhat it can support
SOARS-B, US290 ages 3 to 17; daily flexible-dose nasal oxytocinABC social-withdrawal difference -0.2, 95% CI -1.5 to 1.0; P=0.61No benefit over 24 weeks on measured social or cognitive outcomes
Le pilot, China41 ages 3 to 8; 24 IU every other day plus positive social interactionADOS-2 and SRS-2 improved versus placebo periodA positive combined-intervention pilot that needs independent parallel-group replication
Peng report, ChinaReported n=45, but listed arms sum to 49; bilingual dose wording conflictsSelective emotion-perception signal; anxiety and eye-reading nullAbstract-level signal too internally inconsistent for a clean estimate
TTA-121, Japan109 adult men; enhanced-bioavailability dose-ranging sprayFull-analysis primary comparisons null; per-protocol signal at 6 U/dayProduct-specific exploratory dose work, not confirmation

These studies used different formulations, schedules and outcomes. The Chinese pilot combined oxytocin with structured social interaction, while SOARS-B tested daily dosing over 24 weeks.

SOARS-B · 290 enrolled, primary outcome null

Phase 2 randomized placebo-controlled trial

Sikich L et al. New England Journal of Medicine. 2021

Among 290 randomized participants ages 3 to 17, 139 oxytocin and 138 placebo participants contributed post-baseline primary-outcome data. After 24 weeks, change on the modified ABC Social Withdrawal score differed by -0.2 points between groups (95% CI -1.5 to 1.0; P=0.61). Secondary social and cognitive outcomes generally did not differ, and adverse-event incidence and severity were similar.

Participants / model
290 children and adolescents ages 3 to 17 with autism spectrum disorder
Treatment
Intranasal oxytocin, flexible titration to a target total of 48 IU/day, versus placebo
Follow-up
24 weeks
Study design
Multisite, phase 2, randomized, placebo-controlled, parallel trial; modified intention-to-treat analysis
Funding
US National Institute of Child Health and Human Development

This large disorder-specific trial is more informative for daily autism treatment than single-dose laboratory tasks. It does not test every formulation or paired behavioral intervention.

Read the original source
China pilot · 41 children, paired social interaction

Pilot randomized crossover trial

Le J et al. Psychotherapy and Psychosomatics. 2022

In 41 autistic children ages 3 to 8, six weeks of every-other-day intranasal oxytocin followed by positive social interaction improved ADOS-2 and SRS-2 scores versus the placebo period, with reported P values below 0.001 for total scores. It also changed some secondary behavioral and eye-tracking measures. This was a small pilot crossover study of a combined drug-plus-interaction procedure.

Participants / model
41 autistic children ages 3 to 8 in Chengdu, China; 38 boys and 3 girls in the published table
Treatment
24 IU intranasal oxytocin every other day, followed by 30 minutes of positive social interaction, versus matched placebo period
Follow-up
Two six-week treatment periods separated by a two-week washout
Study design
Double-blind randomized crossover pilot
Funding
Chinese national and institutional grants listed in the paper

The paired social interaction, small sample, crossover design, and highly male sample limit generalization. This result has not displaced the larger parallel-trial null finding.

Read the original source
Guangzhou report · selective signals, inconsistent denominator

Chinese-language randomized trial abstract

Peng R, Jing J, Wei C. Journal of Guangzhou Medical University. 2018;46(3):44-47

The abstract reports eight weeks of oxytocin or placebo in children ages 6 to 12. It reports improvement in ratings of ambiguous happy faces, but no significant improvement in state anxiety or the Reading the Mind in the Eyes task. The abstract says 45 participants yet reports groups of 24 and 25, which sum to 49, and its Chinese and English dose wording is not fully consistent.

Participants / model
Reported as 45 Chinese children ages 6 to 12 with autism spectrum disorder; arm counts are internally inconsistent
Treatment
Nasal oxytocin versus placebo for eight weeks; exact daily dose is ambiguous across the bilingual abstract
Follow-up
Eight weeks with assessment through week 12
Study design
Prospective randomized double-blind placebo-controlled study, published abstract
Funding
2017 Guangdong Medical Science and Technology Research Fund, B2017011

The Chinese and English abstracts report inconsistent denominators and doses, preventing a clean effect estimate.

Read the original source
TTA-121 Japan · product-specific primary analysis null

Randomized multicenter crossover trial

Yamasue H et al. Brain. 2022

Of 109 randomized adult men with high-functioning autism, 103 completed the trial. Across 3, 6, 10, and 20 U/day periods, the prespecified dose-response contrast was not significant in the full analysis set (P=0.182). At 6 U/day, the primary reciprocity score difference versus placebo was -0.5 (95% CI -1.1 to 0.1; P=0.118) in the full analysis set. A per-protocol signal and proposed inverted-U pattern remained exploratory, and no secondary clinical or behavioral outcome improved in the full analysis set.

Participants / model
109 randomized adult men with high-functioning autism at seven Japanese university hospitals
Treatment
TTA-121 enhanced-bioavailability nasal spray at 3, 6, 10, or 20 U/day versus placebo
Follow-up
Four-week treatment periods in a two-period crossover design
Study design
Double-blind, placebo-controlled, multicenter crossover dose-ranging trial
Funding
Non-US government research support; formulation developed for the program

Rabbit-brain exposure was reported as 3.6 times Syntocinon, so these unit doses cannot be assumed equivalent to every spray. The full-analysis primary result was null; a per-protocol result was positive.

Read the original source

Does a nasal dose make people trust or bond more?

The original trust-game result came from a laboratory experiment in 58 men. A much larger registered replication and pooled analysis found no meaningful increase in trust-game behavior. Neither design tested love, relationship quality, consent, or durable bonding.

In 2005, men given 24 IU transferred 17% more money on average in a trust game than placebo participants. In 2026, a registered replication in 211 participants found no effect; pooling it with another large replication yielded 532 participants and placed the effect inside a minimal range.

A task is not a relationship

A one-session money-transfer decision measures behavior under one set of rules. It cannot show that oxytocin improves attachment, empathy, couple stability, or social judgment in daily life.

Kosfeld 2005 · historical trust signal

Randomized double-blind laboratory experiment

Kosfeld M et al. Nature. 2005

In the trust experiment, 58 male investors received 24 IU intranasal oxytocin or placebo 50 minutes before repeated monetary-transfer decisions. Average transfer was 17% higher with oxytocin (P=0.029, one-sided), while a separate nonsocial risk experiment did not differ. This was a laboratory economic endpoint, not a relationship or psychiatric outcome.

Participants / model
58 male investors in the trust experiment; a separate risk experiment included 61 men
Treatment
Single 24 IU dose of Syntocinon nasal spray versus matched placebo
Follow-up
Single laboratory session, testing 50 minutes after administration
Study design
Randomized double-blind placebo-controlled economic-game experiment
Funding
MacArthur Foundation, Cogito Foundation, Swiss National Science Foundation, and University of Zurich program support

The primary paper later published a figure correction for three omitted placebo observations, while stating the statistical tests had included them. Later larger registered replications are essential context.

Read the original source
Kroll 2026 · no meaningful trust effect

Registered replication with pooled equivalence analysis

Kroll CF et al. Cortex. 2026

The 211-person replication found no evidence that intranasal oxytocin increased trust-game behavior. Pooling it with a separate 321-person replication produced 532 participants; equivalence testing placed the effect within a minimal range considered too small to interest most feasible laboratory studies. Baseline trust and reward or punishment sensitivity did not rescue the result.

Participants / model
211 participants in the registered replication; 532 in the pooled analysis
Treatment
Intranasal oxytocin versus placebo in a trust-game paradigm
Follow-up
Single-session laboratory experiments
Study design
Registered replication plus pooled equivalence testing

This measured money-transfer decisions in a laboratory trust game, not relationship quality or bonding.

Read the original source

Does oxytocin treat social anxiety disorder?

A small adjunct trial changed how participants rated their own performance during exposure sessions, but it did not improve the treatment’s overall symptom, cognition, or life-impairment outcomes.

Twenty-five participants received 24 IU or placebo alongside exposure therapy. Positive self-evaluations of appearance and speech improved more with oxytocin as sessions progressed. The broader clinical outcomes improved similarly in both groups.

Social anxiety trial · self-evaluation changed, overall outcome did not

Randomized double-blind adjunct trial

Guastella AJ et al. Psychoneuroendocrinology. 2009

Twenty-five people with primary social anxiety disorder received 24 IU intranasal oxytocin or placebo with exposure therapy. Oxytocin improved positive self-evaluations of appearance and speech during sessions, but did not improve the overall treatment outcome. Symptom severity, dysfunctional cognition, and life impairment fell similarly in both groups.

Participants / model
25 participants with primary social anxiety disorder
Treatment
24 IU intranasal oxytocin or placebo as an adjunct to exposure therapy
Follow-up
Exposure-treatment course; the abstract does not report a durable post-treatment drug effect
Study design
Randomized double-blind placebo-controlled adjunct trial

A situation-specific self-rating change is not the same outcome as remission, disability reduction, or durable anxiety treatment.

Read the original source

Did early oxytocin prevent PTSD after trauma?

The trial missed its primary clinician-rated PTSD outcome and found no overall benefit across follow-up. A more symptomatic subgroup improved in a secondary analysis, which needs confirmation in another trial.

The study randomized 120 distressed emergency-department patients, mostly after accidents. The intention-to-treat analysis included 53 oxytocin and 54 placebo participants. Treatment was 40 IU twice daily for eight days, started within 12 days after trauma, with CAPS assessments through six months. This was prevention soon after trauma, not treatment of established chronic PTSD.

PTSD prevention trial · primary and overall results null

Multicenter randomized double-blind trial

van Zuiden M et al. Biological Psychiatry. 2017

One hundred twenty emergency-department patients with moderate to severe acute distress were randomized, and 107 entered the intention-to-treat analysis. Forty IU twice daily for eight days, begun within 12 days after trauma, did not reduce clinician-rated CAPS scores at 1.5 months or across follow-up. A high-baseline-symptom subgroup signal was secondary and requires replication.

Participants / model
120 adults after trauma, 85% accident victims; intention-to-treat n=107, 53 oxytocin and 54 placebo
Treatment
40 IU intranasal oxytocin twice daily versus placebo
Follow-up
Eight treatment days; follow-up through six months
Study design
Multicenter randomized double-blind placebo-controlled prevention trial
Funding
Non-US government research support

This was early prevention in distressed emergency-department patients, not treatment of established chronic PTSD.

Read the original source

Does intranasal oxytocin improve libido, orgasm, or sexual dysfunction?

It is not a reliable libido or sexual-dysfunction treatment in the controlled data. One small healthy-couple experiment found selective orgasm and partner-interaction rating changes, while better-targeted studies in women found no oxytocin-specific benefit.

What the sexual studies actually measured
StudyPeople and designResult
Healthy couples29 heterosexual couples; 24 IU acute crossoverNo change in drive, arousal, erection, or lubrication; small-to-moderate selective orgasm and post-orgasm ratings, more pronounced in men
Women with sexual dysfunction30 women; 22-week on-demand crossoverPrimary FSFI rose 26% with oxytocin and 31% with placebo; no treatment, sequence, or interaction effect
Healthy women in a laboratory27 women; acute 24 IU crossoverNo subjective or vaginal-photoplethysmography benefit

Endogenous oxytocin changing during sexual response is an association, not proof that an intranasal product treats dysfunction. A single case report can generate a question, but it cannot establish response frequency or causality.

Couples experiment · small selective effects, no increase in sexual drive

Randomized placebo-controlled crossover experiment

Behnia B et al. Hormones and Behavior. 2014

In 29 healthy heterosexual couples, 24 IU intranasal oxytocin did not change sexual drive, arousal, erection, or lubrication. Models found small-to-moderate selective effects on orgasm or post-orgasm ratings and some partner-interaction measures, more pronounced in men. Biomarkers were unchanged.

Participants / model
29 healthy heterosexual couples, 58 participants
Treatment
Single 24 IU intranasal oxytocin dose versus placebo in a naturalistic setting
Follow-up
Acute crossover sessions
Study design
Randomized placebo-controlled naturalistic crossover experiment

This small healthy-couple experiment did not test treatment of diagnosed sexual dysfunction and did not find a general arousal or libido effect.

Read the original source
Sexual dysfunction trial · placebo improved more on the primary scale

Randomized double-blind crossover trial

Muin DA et al. Fertility and Sterility. 2015

Thirty premenopausal and postmenopausal women with sexual dysfunction used 32 IU within 50 minutes before intercourse. Female Sexual Function Index scores increased 26% during oxytocin and 31% during placebo. There was no significant treatment, sequence, or interaction effect across the 22-week crossover trial.

Participants / model
30 premenopausal and postmenopausal women with sexual dysfunction
Treatment
32 IU intranasal oxytocin or placebo within 50 minutes before intercourse
Follow-up
Two eight-week treatment periods, two-week washout, 22 weeks total
Study design
Randomized prospective double-blind placebo-controlled crossover trial

Both periods improved, so before-after change cannot be credited to oxytocin.

Read the original source
Laboratory crossover · subjective and physiologic outcomes null

Double-blind placebo-controlled crossover experiment

Kruger THC et al. Journal of Clinical Psychopharmacology. 2018

In 27 healthy women, a single 24 IU intranasal dose did not change sexual drive, arousal, orgasm-related subjective measures, vaginal photoplethysmography amplitude, or vaginal blood volume compared with placebo.

Participants / model
27 healthy women; mean age 27.5 years
Treatment
Single 24 IU intranasal oxytocin dose versus placebo
Follow-up
Acute laboratory crossover sessions
Study design
Double-blind placebo-controlled crossover laboratory experiment

High internal control comes with limited real-world and clinical-dysfunction generalizability.

Read the original source

Does intranasal oxytocin reach the brain, and when does it act?

Human and animal studies support effects on brain activity after nasal administration. How much oxytocin reaches the brain depends on the formulation and delivery device; a plasma measurement alone does not establish brain exposure.

The Pitocin label gives a plasma half-life of about 1 to 6 minutes for injected oxytocin. That does not measure how long oxytocin remains in the brain after a nasal spray.

TTA-121 developers reported 3.6-fold higher rabbit-brain exposure than Syntocinon. Equal unit doses of those two formulations therefore did not produce equal brain exposure in rabbits.

Pitocin label · indications, route, monitoring, harms

Current US prescribing information

DailyMed, US National Library of Medicine, revised March 2026

The label identifies Pitocin as synthetic oxytocin 10 units/mL for intravenous infusion or intramuscular injection. It covers medically indicated initiation or improvement of uterine contractions, selected abortion management, third-stage uterine contraction, and control of postpartum bleeding or hemorrhage. It says the drug is not indicated for elective induction. Induction or stimulation requires intravenous infusion in a hospital with continuous observation and fetal monitoring.

  • The label reports a plasma half-life of about 1 to 6 minutes.
  • Excess exposure can cause uterine hypertonicity, tetanic contraction, rupture, fetal hypoxia, and death.
  • Its antidiuretic action can cause severe water intoxication with convulsions or coma during prolonged high-dose infusion.
Participants / model
Pregnant and postpartum patients in monitored obstetric care
Treatment
Oxytocin injection, 10 units/mL; intravenous infusion for induction or stimulation and intravenous infusion or intramuscular injection in specified postpartum use
Follow-up
Acute, clinician-controlled obstetric administration
Study design
FDA-regulated product label

A product label defines approved use and warnings. It does not validate intranasal behavioral or sexual uses.

Read the original source
Methods review · route, device, dose, timing, replication

Translational methods review

Quintana DS et al. Molecular Psychiatry. 2021

The review finds converging human and animal evidence that intranasal delivery can produce functionally relevant central effects, while emphasizing unresolved route mechanisms and the need to account for device, dose, timing, preregistration, statistical power, reproducibility, and sex. It does not support treating one CSF timing estimate as a universal nasal half-life.

Participants / model
Human and animal intranasal oxytocin literature
Treatment
Intranasal oxytocin across formulations, devices, and experimental protocols
Follow-up
Literature through 2020
Study design
Narrative translational methods review

A methods review supports interpretation of route and measurement. It is not proof of efficacy for any diagnosis.

Read the original source
TTA-121 Japan · product-specific primary analysis null

Randomized multicenter crossover trial

Yamasue H et al. Brain. 2022

Of 109 randomized adult men with high-functioning autism, 103 completed the trial. Across 3, 6, 10, and 20 U/day periods, the prespecified dose-response contrast was not significant in the full analysis set (P=0.182). At 6 U/day, the primary reciprocity score difference versus placebo was -0.5 (95% CI -1.1 to 0.1; P=0.118) in the full analysis set. A per-protocol signal and proposed inverted-U pattern remained exploratory, and no secondary clinical or behavioral outcome improved in the full analysis set.

Participants / model
109 randomized adult men with high-functioning autism at seven Japanese university hospitals
Treatment
TTA-121 enhanced-bioavailability nasal spray at 3, 6, 10, or 20 U/day versus placebo
Follow-up
Four-week treatment periods in a two-period crossover design
Study design
Double-blind, placebo-controlled, multicenter crossover dose-ranging trial
Funding
Non-US government research support; formulation developed for the program

Rabbit-brain exposure was reported as 3.6 times Syntocinon, so these unit doses cannot be assumed equivalent to every spray. The full-analysis primary result was null; a per-protocol result was positive.

Read the original source

What is known about repeated intranasal safety?

Five autism trials involving 223 participants found no clear excess of the common adverse events assessed. That sample is too small to estimate rare harms, and it does not establish long-term daily safety or safety in pregnancy.

Across five trials and 223 autistic participants, nasal discomfort, irritability, tiredness, diarrhea, and skin irritation were reported, but none was statistically associated with treatment allocation. Severe events were sparse and occurred in both groups: aggression in two oxytocin and one placebo participant, and one seizure in each group.

  • The meta-analysis cannot estimate very rare harms from 223 people.
  • Trial-grade sprays and adverse-event monitoring do not automatically transfer to a compounded or research-market product.
  • Obstetric injection warnings describe a different exposure and setting, but they are a reminder that this peptide has potent peripheral effects.
Safety meta-analysis · 223 participants, narrow evidence base

Systematic review and meta-analysis of randomized trials

Cai Q, Feng L, Yap KZ. Psychiatry and Clinical Neurosciences. 2018

Five autism trials contributed 223 participants, 123 oxytocin and 100 placebo. Common reported events included nasal discomfort 14.3%, irritability 9.0%, tiredness 7.2%, diarrhea 4.5%, and skin irritation 4.5%; none was statistically associated with allocation. Five severe events were reported: aggression in two oxytocin and one placebo participant, and seizures in one participant per group.

Participants / model
223 autistic participants across five randomized trials
Treatment
Repeated intranasal oxytocin versus placebo for at least one month in the included trials
Follow-up
At least one month; studies published before January 1, 2017
Study design
Systematic review and pooled adverse-event analysis

Small trials and inconsistent adverse-event capture cannot rule out uncommon, delayed, pregnancy-related, or formulation-specific harms. Percentages are pooled occurrence, not proven drug-attributable incidence.

Read the original source
Pitocin label · indications, route, monitoring, harms

Current US prescribing information

DailyMed, US National Library of Medicine, revised March 2026

The label identifies Pitocin as synthetic oxytocin 10 units/mL for intravenous infusion or intramuscular injection. It covers medically indicated initiation or improvement of uterine contractions, selected abortion management, third-stage uterine contraction, and control of postpartum bleeding or hemorrhage. It says the drug is not indicated for elective induction. Induction or stimulation requires intravenous infusion in a hospital with continuous observation and fetal monitoring.

  • The label reports a plasma half-life of about 1 to 6 minutes.
  • Excess exposure can cause uterine hypertonicity, tetanic contraction, rupture, fetal hypoxia, and death.
  • Its antidiuretic action can cause severe water intoxication with convulsions or coma during prolonged high-dose infusion.
Participants / model
Pregnant and postpartum patients in monitored obstetric care
Treatment
Oxytocin injection, 10 units/mL; intravenous infusion for induction or stimulation and intravenous infusion or intramuscular injection in specified postpartum use
Follow-up
Acute, clinician-controlled obstetric administration
Study design
FDA-regulated product label

A product label defines approved use and warnings. It does not validate intranasal behavioral or sexual uses.

Read the original source
FDA compounding Q&A · what approval does not cover

Current FDA regulatory guidance page

US Food and Drug Administration, updated 2026

FDA states that compounded drugs are not FDA-approved and that the agency does not verify their safety, effectiveness, or quality before marketing. Compounding may meet an individual need, but facility, formulation, concentration, and device still matter.

Participants / model
US compounded human drugs
Treatment
General compounding framework
Study design
FDA public guidance

This source does not decide whether a particular prescription or preparation satisfies every applicable compounding rule.

Read the original source

Is an intranasal oxytocin product FDA-approved in the United States?

Syntocinon nasal solution once had a US NDA, but its approval was withdrawn in 1997 after the holder stopped marketing it. The 2026 Orange Book lists it as discontinued. A compounded nasal preparation is not an FDA-approved replacement.

Current US product distinction
ProductRecordStatus and implication
Pitocin injectionCurrent DailyMed label; 10 units/mLApproved prescription obstetric product with labeled routes and hospital controls
Syntocinon nasal solutionNDA 012285; 40 USP units/mLApproval withdrawn effective September 8, 1997 after sponsor-requested commercial discontinuation
A pharmacy-compounded nasal sprayPreparation-specific prescription and pharmacy recordNot FDA-approved; FDA has not premarket-verified its safety, effectiveness, or quality

The 1997 notice did not say Syntocinon was withdrawn for danger or ineffectiveness. A current compounded spray still needs its own concentration, ingredients, device, storage instructions and beyond-use date; the former approval does not cover it.

Pitocin label · indications, route, monitoring, harms

Current US prescribing information

DailyMed, US National Library of Medicine, revised March 2026

The label identifies Pitocin as synthetic oxytocin 10 units/mL for intravenous infusion or intramuscular injection. It covers medically indicated initiation or improvement of uterine contractions, selected abortion management, third-stage uterine contraction, and control of postpartum bleeding or hemorrhage. It says the drug is not indicated for elective induction. Induction or stimulation requires intravenous infusion in a hospital with continuous observation and fetal monitoring.

  • The label reports a plasma half-life of about 1 to 6 minutes.
  • Excess exposure can cause uterine hypertonicity, tetanic contraction, rupture, fetal hypoxia, and death.
  • Its antidiuretic action can cause severe water intoxication with convulsions or coma during prolonged high-dose infusion.
Participants / model
Pregnant and postpartum patients in monitored obstetric care
Treatment
Oxytocin injection, 10 units/mL; intravenous infusion for induction or stimulation and intravenous infusion or intramuscular injection in specified postpartum use
Follow-up
Acute, clinician-controlled obstetric administration
Study design
FDA-regulated product label

A product label defines approved use and warnings. It does not validate intranasal behavioral or sexual uses.

Read the original source
Orange Book 2026 · nasal product discontinued

Current FDA drug-product directory

US Food and Drug Administration, Approved Drug Products with Therapeutic Equivalence Evaluations, 46th edition, 2026

The 2026 discontinued-products list includes Syntocinon oxytocin nasal solution, 40 USP units/mL, NDA 012285. The same list separately identifies discontinued injectable oxytocin products. It does not show a currently marketed US nasal oxytocin approval.

Participants / model
US approved-drug product records
Treatment
Syntocinon nasal solution 40 USP units/mL
Follow-up
Directory status as published in 2026
Study design
FDA regulatory directory

Discontinued listing describes market status. The reason for withdrawal comes from the 1997 Federal Register notice.

Read the original source
Federal Register 1997 · why the nasal approval ended

FDA Federal Register notice

US Food and Drug Administration. Federal Register. 1997;62:42575-42577

FDA listed NDA 12-285 Syntocinon oxytocin nasal solution nasal spray among applications whose holders said the products were no longer marketed and requested withdrawal. The withdrawal became effective September 8, 1997. The notice did not make a safety-or-effectiveness finding about this product.

Participants / model
US regulatory record
Treatment
Syntocinon oxytocin nasal solution nasal spray
Follow-up
Withdrawal effective September 8, 1997
Study design
Official administrative notice

Commercial withdrawal is not evidence that current compounded formulations match the former approved product.

Read the original source
FDA compounding Q&A · what approval does not cover

Current FDA regulatory guidance page

US Food and Drug Administration, updated 2026

FDA states that compounded drugs are not FDA-approved and that the agency does not verify their safety, effectiveness, or quality before marketing. Compounding may meet an individual need, but facility, formulation, concentration, and device still matter.

Participants / model
US compounded human drugs
Treatment
General compounding framework
Study design
FDA public guidance

This source does not decide whether a particular prescription or preparation satisfies every applicable compounding rule.

Read the original source

What did the 1955 Nobel Prize actually recognize?

Vincent du Vigneaud’s prize recognized broad work on biologically important sulfur compounds, especially the first synthesis of a polypeptide hormone. His Nobel lecture identifies that hormone as oxytocin.

The disulfide bond made oxytocin central to du Vigneaud’s sulfur research. His group’s work established the structure and chemical synthesis of a biologically active peptide hormone, a major milestone in peptide chemistry.

Nobel record · what the 1955 prize actually recognized

Official Nobel lecture and prize record

du Vigneaud V. Nobel Lecture. December 12, 1955

The Nobel citation recognized work on biochemically important sulfur compounds, especially the first synthesis of a polypeptide hormone. Du Vigneaud identified that hormone as oxytocin and described its uterine-contracting and milk-ejecting biology and the research path to synthesis.

Participants / model
Historical chemistry record
Treatment
Chemical synthesis of oxytocin
Follow-up
Nobel lecture delivered in 1955
Study design
Official historical primary document

The prize recognized work on sulfur compounds, especially the synthesis of a polypeptide hormone.

Read the original source
FDA SRS · molecular identity

Official substance identity record

US Food and Drug Administration, Substance Registration System

FDA records oxytocin under UNII 1JQS135EYN as the cyclic nine-residue peptide CYIQNCPLG with a disulfide link between cysteines 1 and 6 and an amidated glycine terminus.

Participants / model
Not applicable
Treatment
Substance identity only
Follow-up
Not applicable
Study design
Regulatory molecular registry

Identity does not establish a clinical effect for any route or indication.

Read the original source

Why B tier?

Oxytocin has established obstetric uses, but the nasal-spray evidence for autism symptoms, trust and sexual function is inconsistent. Larger trials have often failed to reproduce the benefits suggested by smaller experiments.

  • Approved use: standardized injections for specified obstetric indications, with monitoring during labor induction or stimulation.
  • Nasal research: some small studies reported benefits, while larger autism and trust studies found no meaningful effect on their main outcomes.
  • What would change confidence: independent replication with a fixed product, prespecified clinical endpoint, adequate power, representative population, and useful duration.
Pitocin label · indications, route, monitoring, harms

Current US prescribing information

DailyMed, US National Library of Medicine, revised March 2026

The label identifies Pitocin as synthetic oxytocin 10 units/mL for intravenous infusion or intramuscular injection. It covers medically indicated initiation or improvement of uterine contractions, selected abortion management, third-stage uterine contraction, and control of postpartum bleeding or hemorrhage. It says the drug is not indicated for elective induction. Induction or stimulation requires intravenous infusion in a hospital with continuous observation and fetal monitoring.

  • The label reports a plasma half-life of about 1 to 6 minutes.
  • Excess exposure can cause uterine hypertonicity, tetanic contraction, rupture, fetal hypoxia, and death.
  • Its antidiuretic action can cause severe water intoxication with convulsions or coma during prolonged high-dose infusion.
Participants / model
Pregnant and postpartum patients in monitored obstetric care
Treatment
Oxytocin injection, 10 units/mL; intravenous infusion for induction or stimulation and intravenous infusion or intramuscular injection in specified postpartum use
Follow-up
Acute, clinician-controlled obstetric administration
Study design
FDA-regulated product label

A product label defines approved use and warnings. It does not validate intranasal behavioral or sexual uses.

Read the original source
SOARS-B · 290 enrolled, primary outcome null

Phase 2 randomized placebo-controlled trial

Sikich L et al. New England Journal of Medicine. 2021

Among 290 randomized participants ages 3 to 17, 139 oxytocin and 138 placebo participants contributed post-baseline primary-outcome data. After 24 weeks, change on the modified ABC Social Withdrawal score differed by -0.2 points between groups (95% CI -1.5 to 1.0; P=0.61). Secondary social and cognitive outcomes generally did not differ, and adverse-event incidence and severity were similar.

Participants / model
290 children and adolescents ages 3 to 17 with autism spectrum disorder
Treatment
Intranasal oxytocin, flexible titration to a target total of 48 IU/day, versus placebo
Follow-up
24 weeks
Study design
Multisite, phase 2, randomized, placebo-controlled, parallel trial; modified intention-to-treat analysis
Funding
US National Institute of Child Health and Human Development

This large disorder-specific trial is more informative for daily autism treatment than single-dose laboratory tasks. It does not test every formulation or paired behavioral intervention.

Read the original source
Kroll 2026 · no meaningful trust effect

Registered replication with pooled equivalence analysis

Kroll CF et al. Cortex. 2026

The 211-person replication found no evidence that intranasal oxytocin increased trust-game behavior. Pooling it with a separate 321-person replication produced 532 participants; equivalence testing placed the effect within a minimal range considered too small to interest most feasible laboratory studies. Baseline trust and reward or punishment sensitivity did not rescue the result.

Participants / model
211 participants in the registered replication; 532 in the pooled analysis
Treatment
Intranasal oxytocin versus placebo in a trust-game paradigm
Follow-up
Single-session laboratory experiments
Study design
Registered replication plus pooled equivalence testing

This measured money-transfer decisions in a laboratory trust game, not relationship quality or bonding.

Read the original source
Sexual dysfunction trial · placebo improved more on the primary scale

Randomized double-blind crossover trial

Muin DA et al. Fertility and Sterility. 2015

Thirty premenopausal and postmenopausal women with sexual dysfunction used 32 IU within 50 minutes before intercourse. Female Sexual Function Index scores increased 26% during oxytocin and 31% during placebo. There was no significant treatment, sequence, or interaction effect across the 22-week crossover trial.

Participants / model
30 premenopausal and postmenopausal women with sexual dysfunction
Treatment
32 IU intranasal oxytocin or placebo within 50 minutes before intercourse
Follow-up
Two eight-week treatment periods, two-week washout, 22 weeks total
Study design
Randomized prospective double-blind placebo-controlled crossover trial

Both periods improved, so before-after change cannot be credited to oxytocin.

Read the original source

Studies and sources

Pitocin label · indications, route, monitoring, harms

Current US prescribing information

DailyMed, US National Library of Medicine, revised March 2026

The label identifies Pitocin as synthetic oxytocin 10 units/mL for intravenous infusion or intramuscular injection. It covers medically indicated initiation or improvement of uterine contractions, selected abortion management, third-stage uterine contraction, and control of postpartum bleeding or hemorrhage. It says the drug is not indicated for elective induction. Induction or stimulation requires intravenous infusion in a hospital with continuous observation and fetal monitoring.

  • The label reports a plasma half-life of about 1 to 6 minutes.
  • Excess exposure can cause uterine hypertonicity, tetanic contraction, rupture, fetal hypoxia, and death.
  • Its antidiuretic action can cause severe water intoxication with convulsions or coma during prolonged high-dose infusion.
Participants / model
Pregnant and postpartum patients in monitored obstetric care
Treatment
Oxytocin injection, 10 units/mL; intravenous infusion for induction or stimulation and intravenous infusion or intramuscular injection in specified postpartum use
Follow-up
Acute, clinician-controlled obstetric administration
Study design
FDA-regulated product label

A product label defines approved use and warnings. It does not validate intranasal behavioral or sexual uses.

Read the original source
FDA SRS · molecular identity

Official substance identity record

US Food and Drug Administration, Substance Registration System

FDA records oxytocin under UNII 1JQS135EYN as the cyclic nine-residue peptide CYIQNCPLG with a disulfide link between cysteines 1 and 6 and an amidated glycine terminus.

Participants / model
Not applicable
Treatment
Substance identity only
Follow-up
Not applicable
Study design
Regulatory molecular registry

Identity does not establish a clinical effect for any route or indication.

Read the original source
Orange Book 2026 · nasal product discontinued

Current FDA drug-product directory

US Food and Drug Administration, Approved Drug Products with Therapeutic Equivalence Evaluations, 46th edition, 2026

The 2026 discontinued-products list includes Syntocinon oxytocin nasal solution, 40 USP units/mL, NDA 012285. The same list separately identifies discontinued injectable oxytocin products. It does not show a currently marketed US nasal oxytocin approval.

Participants / model
US approved-drug product records
Treatment
Syntocinon nasal solution 40 USP units/mL
Follow-up
Directory status as published in 2026
Study design
FDA regulatory directory

Discontinued listing describes market status. The reason for withdrawal comes from the 1997 Federal Register notice.

Read the original source
Federal Register 1997 · why the nasal approval ended

FDA Federal Register notice

US Food and Drug Administration. Federal Register. 1997;62:42575-42577

FDA listed NDA 12-285 Syntocinon oxytocin nasal solution nasal spray among applications whose holders said the products were no longer marketed and requested withdrawal. The withdrawal became effective September 8, 1997. The notice did not make a safety-or-effectiveness finding about this product.

Participants / model
US regulatory record
Treatment
Syntocinon oxytocin nasal solution nasal spray
Follow-up
Withdrawal effective September 8, 1997
Study design
Official administrative notice

Commercial withdrawal is not evidence that current compounded formulations match the former approved product.

Read the original source
FDA compounding Q&A · what approval does not cover

Current FDA regulatory guidance page

US Food and Drug Administration, updated 2026

FDA states that compounded drugs are not FDA-approved and that the agency does not verify their safety, effectiveness, or quality before marketing. Compounding may meet an individual need, but facility, formulation, concentration, and device still matter.

Participants / model
US compounded human drugs
Treatment
General compounding framework
Study design
FDA public guidance

This source does not decide whether a particular prescription or preparation satisfies every applicable compounding rule.

Read the original source
SOARS-B · 290 enrolled, primary outcome null

Phase 2 randomized placebo-controlled trial

Sikich L et al. New England Journal of Medicine. 2021

Among 290 randomized participants ages 3 to 17, 139 oxytocin and 138 placebo participants contributed post-baseline primary-outcome data. After 24 weeks, change on the modified ABC Social Withdrawal score differed by -0.2 points between groups (95% CI -1.5 to 1.0; P=0.61). Secondary social and cognitive outcomes generally did not differ, and adverse-event incidence and severity were similar.

Participants / model
290 children and adolescents ages 3 to 17 with autism spectrum disorder
Treatment
Intranasal oxytocin, flexible titration to a target total of 48 IU/day, versus placebo
Follow-up
24 weeks
Study design
Multisite, phase 2, randomized, placebo-controlled, parallel trial; modified intention-to-treat analysis
Funding
US National Institute of Child Health and Human Development

This large disorder-specific trial is more informative for daily autism treatment than single-dose laboratory tasks. It does not test every formulation or paired behavioral intervention.

Read the original source
China pilot · 41 children, paired social interaction

Pilot randomized crossover trial

Le J et al. Psychotherapy and Psychosomatics. 2022

In 41 autistic children ages 3 to 8, six weeks of every-other-day intranasal oxytocin followed by positive social interaction improved ADOS-2 and SRS-2 scores versus the placebo period, with reported P values below 0.001 for total scores. It also changed some secondary behavioral and eye-tracking measures. This was a small pilot crossover study of a combined drug-plus-interaction procedure.

Participants / model
41 autistic children ages 3 to 8 in Chengdu, China; 38 boys and 3 girls in the published table
Treatment
24 IU intranasal oxytocin every other day, followed by 30 minutes of positive social interaction, versus matched placebo period
Follow-up
Two six-week treatment periods separated by a two-week washout
Study design
Double-blind randomized crossover pilot
Funding
Chinese national and institutional grants listed in the paper

The paired social interaction, small sample, crossover design, and highly male sample limit generalization. This result has not displaced the larger parallel-trial null finding.

Read the original source
Guangzhou report · selective signals, inconsistent denominator

Chinese-language randomized trial abstract

Peng R, Jing J, Wei C. Journal of Guangzhou Medical University. 2018;46(3):44-47

The abstract reports eight weeks of oxytocin or placebo in children ages 6 to 12. It reports improvement in ratings of ambiguous happy faces, but no significant improvement in state anxiety or the Reading the Mind in the Eyes task. The abstract says 45 participants yet reports groups of 24 and 25, which sum to 49, and its Chinese and English dose wording is not fully consistent.

Participants / model
Reported as 45 Chinese children ages 6 to 12 with autism spectrum disorder; arm counts are internally inconsistent
Treatment
Nasal oxytocin versus placebo for eight weeks; exact daily dose is ambiguous across the bilingual abstract
Follow-up
Eight weeks with assessment through week 12
Study design
Prospective randomized double-blind placebo-controlled study, published abstract
Funding
2017 Guangdong Medical Science and Technology Research Fund, B2017011

The Chinese and English abstracts report inconsistent denominators and doses, preventing a clean effect estimate.

Read the original source
TTA-121 Japan · product-specific primary analysis null

Randomized multicenter crossover trial

Yamasue H et al. Brain. 2022

Of 109 randomized adult men with high-functioning autism, 103 completed the trial. Across 3, 6, 10, and 20 U/day periods, the prespecified dose-response contrast was not significant in the full analysis set (P=0.182). At 6 U/day, the primary reciprocity score difference versus placebo was -0.5 (95% CI -1.1 to 0.1; P=0.118) in the full analysis set. A per-protocol signal and proposed inverted-U pattern remained exploratory, and no secondary clinical or behavioral outcome improved in the full analysis set.

Participants / model
109 randomized adult men with high-functioning autism at seven Japanese university hospitals
Treatment
TTA-121 enhanced-bioavailability nasal spray at 3, 6, 10, or 20 U/day versus placebo
Follow-up
Four-week treatment periods in a two-period crossover design
Study design
Double-blind, placebo-controlled, multicenter crossover dose-ranging trial
Funding
Non-US government research support; formulation developed for the program

Rabbit-brain exposure was reported as 3.6 times Syntocinon, so these unit doses cannot be assumed equivalent to every spray. The full-analysis primary result was null; a per-protocol result was positive.

Read the original source
Kosfeld 2005 · historical trust signal

Randomized double-blind laboratory experiment

Kosfeld M et al. Nature. 2005

In the trust experiment, 58 male investors received 24 IU intranasal oxytocin or placebo 50 minutes before repeated monetary-transfer decisions. Average transfer was 17% higher with oxytocin (P=0.029, one-sided), while a separate nonsocial risk experiment did not differ. This was a laboratory economic endpoint, not a relationship or psychiatric outcome.

Participants / model
58 male investors in the trust experiment; a separate risk experiment included 61 men
Treatment
Single 24 IU dose of Syntocinon nasal spray versus matched placebo
Follow-up
Single laboratory session, testing 50 minutes after administration
Study design
Randomized double-blind placebo-controlled economic-game experiment
Funding
MacArthur Foundation, Cogito Foundation, Swiss National Science Foundation, and University of Zurich program support

The primary paper later published a figure correction for three omitted placebo observations, while stating the statistical tests had included them. Later larger registered replications are essential context.

Read the original source
Kroll 2026 · no meaningful trust effect

Registered replication with pooled equivalence analysis

Kroll CF et al. Cortex. 2026

The 211-person replication found no evidence that intranasal oxytocin increased trust-game behavior. Pooling it with a separate 321-person replication produced 532 participants; equivalence testing placed the effect within a minimal range considered too small to interest most feasible laboratory studies. Baseline trust and reward or punishment sensitivity did not rescue the result.

Participants / model
211 participants in the registered replication; 532 in the pooled analysis
Treatment
Intranasal oxytocin versus placebo in a trust-game paradigm
Follow-up
Single-session laboratory experiments
Study design
Registered replication plus pooled equivalence testing

This measured money-transfer decisions in a laboratory trust game, not relationship quality or bonding.

Read the original source
Social anxiety trial · self-evaluation changed, overall outcome did not

Randomized double-blind adjunct trial

Guastella AJ et al. Psychoneuroendocrinology. 2009

Twenty-five people with primary social anxiety disorder received 24 IU intranasal oxytocin or placebo with exposure therapy. Oxytocin improved positive self-evaluations of appearance and speech during sessions, but did not improve the overall treatment outcome. Symptom severity, dysfunctional cognition, and life impairment fell similarly in both groups.

Participants / model
25 participants with primary social anxiety disorder
Treatment
24 IU intranasal oxytocin or placebo as an adjunct to exposure therapy
Follow-up
Exposure-treatment course; the abstract does not report a durable post-treatment drug effect
Study design
Randomized double-blind placebo-controlled adjunct trial

A situation-specific self-rating change is not the same outcome as remission, disability reduction, or durable anxiety treatment.

Read the original source
PTSD prevention trial · primary and overall results null

Multicenter randomized double-blind trial

van Zuiden M et al. Biological Psychiatry. 2017

One hundred twenty emergency-department patients with moderate to severe acute distress were randomized, and 107 entered the intention-to-treat analysis. Forty IU twice daily for eight days, begun within 12 days after trauma, did not reduce clinician-rated CAPS scores at 1.5 months or across follow-up. A high-baseline-symptom subgroup signal was secondary and requires replication.

Participants / model
120 adults after trauma, 85% accident victims; intention-to-treat n=107, 53 oxytocin and 54 placebo
Treatment
40 IU intranasal oxytocin twice daily versus placebo
Follow-up
Eight treatment days; follow-up through six months
Study design
Multicenter randomized double-blind placebo-controlled prevention trial
Funding
Non-US government research support

This was early prevention in distressed emergency-department patients, not treatment of established chronic PTSD.

Read the original source
Couples experiment · small selective effects, no increase in sexual drive

Randomized placebo-controlled crossover experiment

Behnia B et al. Hormones and Behavior. 2014

In 29 healthy heterosexual couples, 24 IU intranasal oxytocin did not change sexual drive, arousal, erection, or lubrication. Models found small-to-moderate selective effects on orgasm or post-orgasm ratings and some partner-interaction measures, more pronounced in men. Biomarkers were unchanged.

Participants / model
29 healthy heterosexual couples, 58 participants
Treatment
Single 24 IU intranasal oxytocin dose versus placebo in a naturalistic setting
Follow-up
Acute crossover sessions
Study design
Randomized placebo-controlled naturalistic crossover experiment

This small healthy-couple experiment did not test treatment of diagnosed sexual dysfunction and did not find a general arousal or libido effect.

Read the original source
Sexual dysfunction trial · placebo improved more on the primary scale

Randomized double-blind crossover trial

Muin DA et al. Fertility and Sterility. 2015

Thirty premenopausal and postmenopausal women with sexual dysfunction used 32 IU within 50 minutes before intercourse. Female Sexual Function Index scores increased 26% during oxytocin and 31% during placebo. There was no significant treatment, sequence, or interaction effect across the 22-week crossover trial.

Participants / model
30 premenopausal and postmenopausal women with sexual dysfunction
Treatment
32 IU intranasal oxytocin or placebo within 50 minutes before intercourse
Follow-up
Two eight-week treatment periods, two-week washout, 22 weeks total
Study design
Randomized prospective double-blind placebo-controlled crossover trial

Both periods improved, so before-after change cannot be credited to oxytocin.

Read the original source
Laboratory crossover · subjective and physiologic outcomes null

Double-blind placebo-controlled crossover experiment

Kruger THC et al. Journal of Clinical Psychopharmacology. 2018

In 27 healthy women, a single 24 IU intranasal dose did not change sexual drive, arousal, orgasm-related subjective measures, vaginal photoplethysmography amplitude, or vaginal blood volume compared with placebo.

Participants / model
27 healthy women; mean age 27.5 years
Treatment
Single 24 IU intranasal oxytocin dose versus placebo
Follow-up
Acute laboratory crossover sessions
Study design
Double-blind placebo-controlled crossover laboratory experiment

High internal control comes with limited real-world and clinical-dysfunction generalizability.

Read the original source
Safety meta-analysis · 223 participants, narrow evidence base

Systematic review and meta-analysis of randomized trials

Cai Q, Feng L, Yap KZ. Psychiatry and Clinical Neurosciences. 2018

Five autism trials contributed 223 participants, 123 oxytocin and 100 placebo. Common reported events included nasal discomfort 14.3%, irritability 9.0%, tiredness 7.2%, diarrhea 4.5%, and skin irritation 4.5%; none was statistically associated with allocation. Five severe events were reported: aggression in two oxytocin and one placebo participant, and seizures in one participant per group.

Participants / model
223 autistic participants across five randomized trials
Treatment
Repeated intranasal oxytocin versus placebo for at least one month in the included trials
Follow-up
At least one month; studies published before January 1, 2017
Study design
Systematic review and pooled adverse-event analysis

Small trials and inconsistent adverse-event capture cannot rule out uncommon, delayed, pregnancy-related, or formulation-specific harms. Percentages are pooled occurrence, not proven drug-attributable incidence.

Read the original source
Methods review · route, device, dose, timing, replication

Translational methods review

Quintana DS et al. Molecular Psychiatry. 2021

The review finds converging human and animal evidence that intranasal delivery can produce functionally relevant central effects, while emphasizing unresolved route mechanisms and the need to account for device, dose, timing, preregistration, statistical power, reproducibility, and sex. It does not support treating one CSF timing estimate as a universal nasal half-life.

Participants / model
Human and animal intranasal oxytocin literature
Treatment
Intranasal oxytocin across formulations, devices, and experimental protocols
Follow-up
Literature through 2020
Study design
Narrative translational methods review

A methods review supports interpretation of route and measurement. It is not proof of efficacy for any diagnosis.

Read the original source
Nobel record · what the 1955 prize actually recognized

Official Nobel lecture and prize record

du Vigneaud V. Nobel Lecture. December 12, 1955

The Nobel citation recognized work on biochemically important sulfur compounds, especially the first synthesis of a polypeptide hormone. Du Vigneaud identified that hormone as oxytocin and described its uterine-contracting and milk-ejecting biology and the research path to synthesis.

Participants / model
Historical chemistry record
Treatment
Chemical synthesis of oxytocin
Follow-up
Nobel lecture delivered in 1955
Study design
Official historical primary document

The prize recognized work on sulfur compounds, especially the synthesis of a polypeptide hormone.

Read the original source

Why is oxytocin in B tier?

B tier reflects established obstetric uses alongside inconsistent findings from nasal-spray research. Larger autism and trust studies found no meaningful benefit on their main outcomes, and long-term safety data for daily behavioral use remain limited.

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