Oxytocin (intranasal): what the evidence shows

What the human research shows

One of the most-studied peptides in psychiatry, and a cautionary tale about promising pilot data. The injectable hormone is genuine, licensed obstetric medicine. The nasal spray that people actually buy has been through large, careful randomised trials — and mostly failed them.

Evidence profile0–5

Metabolic & weightC0.7
Cardiovascular—0.0
Muscle & growth—0.0
Healing & repair—0.0
Neuro & sleepB0.0
Immune & inflammation—0.0
Sexual & hormonal—0.0
Skin & appearance—0.0
Ageing & longevity—0.0

Each score is confidence × effect size, taken from the best-evidenced benefit in that domain: the grade (A–D) sets the confidence, the measured effect sets the size. Hover a domain to see the outcomes behind it. Adverse effects are excluded and listed separately below.

Outcome	Grade	Effect size	Human studies	Where the evidence comes from
Social function in autism	BProbable	Not measurable	1 large phase 2 RCT (n=290)	SOARS-B, the definitive 24-week trial in children and adolescents, found no difference from placebo on its primary social-withdrawal measure or on secondary outcomes.1
Weight loss in obesity	CWeak	Not measurable	1 RCT (n=61)	Eight weeks of intranasal oxytocin four times daily produced no weight change versus placebo, though it modestly reduced intake at a single test meal.2
Appetite / caloric intake (acute)	CWeak	Small	Small crossover studies	A single dose lowered food intake at a laboratory test meal in the obesity trial and in earlier crossover work — an acute effect that did not translate into weight change over eight weeks.2
Safety (intranasal, short-term)adverse	BProbable	Small	Multiple RCTs	Short-term intranasal use is well tolerated, with adverse events similar to placebo in the large trials. Long-term safety of daily self-dosing is not established.1

AMultiple good human trials, consistentBSome human trials, mostly consistentCFew or weak human studiesDAnimal or anecdotal onlyeffect size · red = adverse

Literature searched to 3 September 2026. Human studies only; animal and cell work informs the mechanism section and nothing else.

Registered trials

ClinicalTrials.gov lists 157+ interventional studies naming Oxytocin (intranasal) as an intervention — 92 completed, 15 recruiting, and 30 with results posted to the registry.

A registration is not a result. Anyone can register a study, and many never report — so this list shows what has been attempted, not what has been shown. The graded evidence above is the answer to whether something works.

Study	Phase	Status	Participants	Sponsor	Results
Low-Dose Versus High-Dose Oxytocin Dosing for Induction and Augmentation of LaborNCT05782816 · started Apr 2023	Phase 4	Completed	170	The University of Texas Medical Branch, Galveston	Posted
Effects of Intranasal Oxytocin on Cigarette SmokingNCT02595749 · started Jul 2016	Phase 4	Completed	83	University of Southern California	Posted
Carbetocin Versus Oxytocin and Hemodynamic EffectsNCT00977769 · started Nov 2009	Phase 4	Completed	76	Oslo University Hospital	Posted
Intranasal Oxytocin and Social Cognition, Implicit Preferences and Craving in Alcohol DrinkersNCT01829516 · started May 2013	Phase 4	Completed	32	University of California, San Francisco	Posted
Effects of Intranasal Oxytocin on Satiety Signaling in People With SchizophreniaNCT01614093 · started Jun 2012	Phase 4	Completed	24	University of Maryland, Baltimore	Posted
Study of the Effectiveness of Cervical Ripening Balloon With and Without OxytocinNCT03138252 · started Nov 2014	Phase 3	Completed	180	University Hospitals Cleveland Medical Center	Posted
High Dose Oxytocin Nasal Spray for Treatment of TinnitusNCT04210310 · started Jan 2020	Phase 3	Terminated	33	NYU Langone Health	Posted
Study of Oxytocin in Autism to Improve Reciprocal Social BehaviorsNCT01944046 · started Aug 2014	Phase 2	Completed	290	Linmarie Sikich	Posted

149 further studies are registered. Participant counts marked * are the sponsor's estimate, not a final enrolment. Source: ClinicalTrials.gov, read directly from the registry and refreshed weekly.

What it is

Oxytocin is a nine-amino-acid peptide hormone made in the hypothalamus. As an injection it is core obstetric medicine — inducing labour, controlling postpartum bleeding — and has been licensed for that for more than half a century.

The 'oxytocin' of wellness and peptide marketing is a nasal spray aimed at bonding, trust, appetite and social behaviour. That is a different route, a different dose and a different evidence base from the licensed injection.

How it is thought to work

Given intranasally, a small and debated fraction may reach the brain and act on oxytocin receptors involved in social and feeding behaviour. Whether enough reaches central targets to matter, and in whom, is exactly what the large trials were designed to settle — and their answer, for autism and for weight, was no.

What is still unknown

Whether any subgroup benefits from intranasal oxytocin where the overall trials were null.
How much intranasal oxytocin actually reaches the brain.
Long-term safety and hormonal effects of chronic self-administration.

The molecule and how long it lasts

Identity

Formula: C43H66N12O12S2
Molecular weight: 1007.2 g/mol
CAS number: 50-56-6
PubChem: CID 439302

PubChem record, read 23 September 2026.

Pharmacokinetics

Route: Intravenous infusion (labour) or intramuscular injection (postpartum)
Half-life: About 1-6 minutes
Licensed regimen (Pitocin): Labour induction: IV infusion 0.5-1 mU/min initially, increased by 1-2 mU/min every 30-60 min; postpartum: 10-40 units IV infusion or 10 units IM

From the approved product's prescribing information: Pitocin prescribing information (DailyMed) The regimen is the label's own wording, reproduced as a regulatory fact.

Regulatory status

European Union

Approved as injection; nasal use unlicensed

Oxytocin injection is authorised across the EU for obstetric use. A nasal spray (Syntocinon) was historically used for breastfeeding; general 'bonding' or weight use is off-label or unlicensed.

United States

Approved as injection (Pitocin)

The injection is FDA-approved for obstetric indications. Intranasal oxytocin is not FDA-approved and is sold via compounding pharmacies and the grey market.

United Kingdom

Licensed as injection

Syntocinon injection is MHRA-licensed for obstetric use; other routes and indications are unlicensed.

Australia

Registered as injection

Injectable oxytocin is on the ARTG for obstetric use; intranasal products are not registered for the marketed 'wellness' uses.

Canada

Authorised as injection

Injectable oxytocin carries a DIN; nasal 'wellness' products do not.

Sport (WADA)

Not prohibited

Not on the 2026 Prohibited List.

Questions people actually ask

Does oxytocin nasal spray help autism?

The largest randomised trial (SOARS-B, 290 children and adolescents over 24 weeks) found no benefit over placebo on social function. Earlier small studies had been more encouraging; the definitive trial was not.

Will oxytocin help me lose weight?

In a randomised trial, eight weeks of intranasal oxytocin produced no weight change versus placebo. It reduced intake at a single test meal, which did not translate into weight loss.

Is the injection different from the spray?

Yes. Injectable oxytocin is licensed obstetric medicine. The nasal spray sold for bonding and appetite is a different route and dose, and its marketed uses are largely unsupported by the big trials.

One page per claimed effect

BDoes Oxytocin (intranasal) help with social function in autism?1 large phase 2 RCT (n=290)
CDoes Oxytocin (intranasal) help with weight loss in obesity?1 RCT (n=61)
CDoes Oxytocin (intranasal) help with appetite / caloric intake?Small crossover studies
BHow common is safety with Oxytocin (intranasal)?Multiple RCTs

References

1
Sikich L, et al. Intranasal oxytocin in children and adolescents with autism spectrum disorder (SOARS-B).N Engl J Med, 2021;385:1462–1473290 participants, 24 weeks; primary and secondary outcomes null.
2
Plessow F, et al. Intranasal oxytocin for obesity.NEJM Evidence, 2024;3:EVIDoa230034961 adults, 8 weeks; no weight change, reduced single-meal intake.

Change log

2026-09-03Initial publication. Grades reflect large, well-conducted but mostly null intranasal trials.