Oxytocin (Syntocinon): use in childbirth, nasal spray research and side effects
In short
Oxytocin is a peptide hormone the body makes itself, and in synthetic form it is an approved hospital medicine for inducing labour and treating bleeding [1] [4]official. As a nasal spray, large trials have not shown a benefit [5, 7]A.
- In childbirth, oxytocin is given in hospital into a vein or muscle, and contractions and the fetal heart rate are monitored throughout [4]official.
- The best evidence concerns preventing bleeding: according to a Cochrane review, oxytocin given after the birth may reduce blood loss of 500 ml or more [3]A.
- The nasal spray did not help social symptoms of autism in a trial of 290 children and adolescents or in a meta-analysis of 12 trials [5, 7]A.
- In Finland oxytocin is on the medicines list, and the products recorded for Finland are given into a vein or muscle; no nasal spray was recorded for Finland [13, 15]regulator.
What is oxytocin?
Oxytocin is a peptide hormone produced in the hypothalamus of the brain and released into the circulation from the posterior pituitary [1, 2]. During labour it is released in pulses of increasing frequency, and it contracts the uterus [1]. It also regulates the female reproductive system during breastfeeding [2].
Synthetic oxytocin is an approved medicine. In the EMA Article 57 product list (data as of 21 Sep 2026), oxytocin (Syntocinon) for use into a vein or muscle and a second oxytocin product for use into a vein were recorded for Finland [13]regulator. The EMA data set of centrally authorised medicines contained no oxytocin on 12 Oct 2026, so the products are authorised nationally [14]regulator [13]regulator.
Oxytocin used as a nasal spray is a different matter from the hospital labour medicine: it has been studied for social behaviour and mental disorders [5, 8]A. Basics: What are peptides?. All substances: Peptides A-Z.
Evidence at a glance
Each cell gives the kind of study and its source. The letter is the evidence level, not the result.
| Claimed effect | Humans | Animals | Cells |
|---|---|---|---|
| Preventing bleeding after birth | Cochrane review, 24 trials: may reduce blood loss of 500 ml or more [3]A | - | - |
| Inducing and augmenting labour | Approved indication [4]official; a high dose may shorten labour, does not reduce caesarean sections [1] | - | - |
| Social symptoms of autism (nasal spray) | No difference from placebo in 290 children [5]A; meta-analysis of 12 trials, no effect [7]A | - | - |
| Mental disorders (nasal spray) | Meta-analysis of 42 trials: overall effect small, not significant [8]A | - | - |
| Trust and attachment | The early finding has not replicated well [10] | In animals a key role in attachment [10]C | - |
| Safety | Serious harms possible in hospital use [4]official; short-term nasal spray use did not differ from placebo [11], nor did the most common harms in long-term autism trials [12]A | - | - |
"-" = no such study is known.
What is oxytocin used for?
The approved use of oxytocin is in hospital around childbirth. The uses of the nasal spray are research topics, not approved indications in Finland [13]regulator.
- Inducing and augmenting labour: according to the US label, for a medical reason, such as pre-eclampsia or prematurely ruptured membranes, and to reinforce weak contractions [4]official.
- Bleeding after childbirth: to contract the uterus in the third stage of labour and to control bleeding [4]official. Preventive use has been assessed in a Cochrane review [3]A.
- Nasal spray (research use): autism [5, 6, 7]A, mental disorders [8]A and trust [10]. According to one trial, the nasal spray has been given in clinical practice to many children with autism spectrum disorder [5]A.
Not without a medical reason. In the United States, oxytocin (Pitocin) is not indicated for inducing labour without a medical reason, because the available data are inadequate to evaluate benefits and risks [4]official.
How does oxytocin work?
Oxytocin contracts the uterus by binding to oxytocin receptors in the uterine muscle [1]. According to the label, there are many more receptors during pregnancy, and their number peaks in early labour. That is why the same dose works very differently in different people [4]official.
Oxytocin differs from the hormone vasopressin in only two amino acids, and at large doses it raises blood pressure and reduces water loss [4]official. The brain oxytocin system has been linked to lower fear, pain and stress in women giving birth, but there is no firm evidence on long-term effects on mother and child [1].
Has oxytocin been studied in humans?
Yes, extensively. There are Cochrane reviews of its use in childbirth, and large randomised placebo-controlled trials and meta-analyses of the nasal spray [3, 5, 7, 8]A.
Childbirth
- Preventing bleeding. A Cochrane review included 24 trials, 23 of which contributed data from more than 10,000 women. Oxytocin given preventively after the baby is born may reduce blood loss of 500 ml or more and probably reduces the need for additional medicines compared with placebo or no treatment. Evidence quality ranged from very low to moderate [3]A.
- Augmenting labour. According to a review, a high-dose oxytocin infusion may shorten labour by up to two hours compared with no infusion, but it does not lower the rate of caesarean section [1].
Nasal spray
- Autism, children and adolescents (2021). In a 24-week trial, 290 children and adolescents (aged 3 to 17) received oxytocin or placebo into the nose. Social withdrawal scores improved almost equally in both groups (-3.7 and -3.5), and the difference was not significant [5]A.
- Autism, young children (2023). In a 12-week trial of 87 children (aged 3 to 12), oxytocin did not improve caregiver-rated social responsiveness overall. Signs of benefit were seen in children aged 3-5, but not in clinician ratings or other measures [6]A.
- Meta-analyses (2026). In a meta-analysis of 12 randomised trials (733 participants), oxytocin had no effect on social symptoms of autism [7]A. In a meta-analysis of 42 trials (1,922 participants) in mental disorders, the overall effect was small and not statistically significant; a small significant effect was found in schizophrenia spectrum disorders [8]A.
- Trust. According to a review, the early finding that oxytocin increases trust has not replicated well [10].
Who studies oxytocin?
Oxytocin’s use in childbirth is assessed in Cochrane reviews and obstetric reviews [1, 2, 3]. Quality and storage have been reviewed to support international recommendations [16]. The nasal spray has been studied in, among others, an autism trial of 290 children and adolescents [5]A and a trial in young children [6]A.
Author of this page: the editorial team
This page was written by the Molecular Recovery editorial team. The draft was made with the help of AI, and the claims were checked against the sources (AI policy). The page has not been medically reviewed. How we work: About us.
How long does oxytocin stay in the body?
Oxytocin stays in the body for a very short time. According to the US label, the half-life of oxytocin in plasma is about 1 to 6 minutes, and it is shorter in late pregnancy and during breastfeeding [4]official.
Given into a vein, the uterus responds almost immediately and the effect subsides within an hour. Given into a muscle, the effect starts within 3 to 5 minutes and lasts 2 to 3 hours. Oxytocin is removed from the blood mainly by the kidneys and the liver [4]official.
For the nasal spray, according to a review, very little of the large amounts given appears to reach the cerebrospinal fluid, but blood levels rise above natural levels [9].
What are the side effects of oxytocin?
In hospital use oxytocin can cause serious harm, which is why it is only given under supervision [4]official. Short-term use of the nasal spray in trials caused no harms that differed from placebo [11] [12]A.
Hospital use in childbirth
According to the US product label, oxytocin (Pitocin) for inducing or augmenting labour is given only into a vein and with adequate medical supervision in a hospital. Excessive dosage or hypersensitivity can cause excessive or spasm-like uterine contractions and even rupture of the uterus [4]official.
The same label describes severe water intoxication with convulsions and coma during a slow infusion lasting 24 hours, and maternal deaths due to water intoxication have been reported. Reported harms in the fetus or newborn include slow heart rate and arrhythmias [4]official.
According to a review, oxytocin used in error can harm patients, which is why it is given by infusion pump and contractions and the fetal heart rate are closely monitored [2].
Nasal spray
In a review of 38 trials, short-term use of 18-40 IU in research settings caused no harms that differed from placebo, but three case reports of adverse reactions from misuse and longer-term use were found [11]. In a meta-analysis of long-term autism trials the most common adverse events were nasal discomfort, tiredness and irritability, and they were not more common with oxytocin than with placebo [12]A. In a large autism trial, the incidence and severity of adverse events were similar in the two groups [5]A.
According to a review, the nasal spray raises blood oxytocin above natural levels, which may affect for example the gut, the heart and the reproductive tract [9]. More: Side effects and safety.
Interactions and who has no data
According to the US label, severe high blood pressure has been reported when oxytocin was given 3 to 4 hours after a vasoconstrictor used with regional anaesthesia. Certain anaesthetics (cyclopropane) can change the effects of oxytocin on the heart and circulation [4]official.
The same label states that there are no animal or human studies of the effect of oxytocin on cancer risk, genes or fertility [4]official. On long-term use of the nasal spray there are only individual case reports [11].
What speaks against it and what is unknown
In childbirth the benefit of oxytocin has been shown, but for the nasal spray the largest and best trials have been negative [5, 7]A.
Evidence against
- In an autism trial of 290 children and adolescents, oxytocin did not differ from placebo on measures of social or cognitive functioning over 24 weeks [5]A.
- A 2026 meta-analysis of 12 trials found no effect on social symptoms of autism [7]A.
- In mental disorders the overall effect was small and not statistically significant [8]A.
- A high-dose infusion did not reduce caesarean sections [1].
What the evidence does not support
- "Oxytocin is a love hormone that increases trust": the early finding has not replicated well, and the cumulative evidence does not show that oxytocin reliably increases human trust [10].
- "The nasal spray helps autism": not in large trials or a meta-analysis [5, 7]A.
- "Oxytocin from a nasal spray goes straight to the brain": very little appears to reach the cerebrospinal fluid [9].
- "Oxytocin used in childbirth and a nasal spray are the same thing": the substance is the same, the use is not. In childbirth oxytocin is given into a vein in hospital under medical supervision [4]official, and no oxytocin product for use in the nose was recorded for Finland [13]regulator.
What is unknown
- Whether any group benefits from the nasal spray. A small trial saw signs of benefit in children aged 3-5, but according to the authors the result needs further trials [6]A.
- Whether oxytocin works in schizophrenia. A meta-analysis found a small effect, but according to the authors trial methods seldom matched best practice [8]A.
- The safety of long-term nasal spray use: the data mainly concern short-term use in research settings [11].
- How much intranasal oxytocin reaches the brain. According to a review, proper dose-response studies are needed [9].
Oxytocin dosage in studies
Oxytocin has an approved dosage only for hospital use in childbirth. According to the label, the dose is determined by the uterine response, started at a very low level and individualised [4]official. The nasal spray has no approved dosage in Finland [13]regulator; the nasal spray doses below are study doses.
| Study or text | Who | Dose and route | Duration |
|---|---|---|---|
| Pitocin label (United States) | induction or augmentation of labour in hospital | infusion into a vein, starting at 0.5-1 mU/min, raised every 30-60 minutes by 1-2 mU/min | until the desired contraction pattern [4]official |
| Pitocin label (United States) | bleeding after childbirth | 10-40 units added to an infusion (maximum 40 units per litre) or 10 units into a muscle after delivery of the placenta | infusion rate adjusted to keep the uterus contracted [4]official |
| Obstetric review (2024) | induction and augmentation of labour | infusion into a vein from 1-3 mIU/min up to 36 mIU/min; after the birth often 5-10 IU into a vein or muscle | during labour [1] |
| Autism (2021) | 290 children and adolescents, aged 3-17 | target dose 48 IU a day into the nose | 24 weeks [5]A |
| Autism (2023) | 87 children, aged 3-12 | 16 IU twice a day (32 IU a day) into the nose | 12 weeks [6]A |
| Nasal spray review (2011) | trial participants, mostly healthy | 18-40 IU into the nose, mostly as a single dose | short-term [11] |
What the numbers do not tell you. Hospital doses are infusions adjusted by staff while contractions and the fetal heart rate are monitored throughout [4]official [2]. The nasal spray doses come from trials that showed no benefit [5, 7]A. None of the figures is a recommendation. The doses in the summary of product characteristics of Syntocinon, the product used in Finland, are on Oxytocin dosage; the calculator has no preset for oxytocin.
Situation in the United States
In the United States, oxytocin (Pitocin) is an approved injectable medicine. According to its label, it is not indicated for inducing labour without a medical reason, because the available data are inadequate to evaluate benefits and risks [4]official.
Is oxytocin legal in Finland?
Oxytocin is a medicine in Finland: it is in annex 1 of the medicines list, which lists substances in medicinal use in Finland [15]regulator.
- Products. In the EMA Article 57 data, the oxytocin products recorded for Finland are given into a vein or muscle (data as of 21 Sep 2026) [13]regulator.
- Nasal spray. In the same list, oxytocin products for use in the nose were recorded for Sweden, Norway, Croatia and Slovenia, but not for Finland [13]regulator.
- Fimea warning, 29 June 2026. According to Fimea, a product injected through the skin may be a medicine in Finland, medicines should be obtained only from legal sources, and there are restrictions on importing medicines and receiving them by post from abroad. A product labelled "for research use only" is not intended for humans [18]regulator.
- Import. Ordering medicines from outside the EU is covered on Peptides and the law in Finland. Bringing them back from travel: Travelling with peptides.
This is not legal advice. Disclaimer.
How is an oxytocin product assessed?
An authorised product from a pharmacy is the only way to know what the pack contains. According to Fimea, an unauthorised product may contain a different substance than the packaging states [18]regulator.
Oxytocin is sensitive to heat. According to a review written to support international recommendations, oxytocin should be kept at 2-8 degrees throughout the supply chain, because cumulative heat exposure degrades it [16]. In a review of oxytocin samples from low- and middle-income countries, a median of 45.6% of samples failed quality tests, mostly because of too little active ingredient [17]. These figures concern injections intended as medicines and do not tell the quality of sprays sold online.
A certificate of analysis (COA) does not show that a product is safe. More: How to read a COA and check a test result.
FAQ
Oxytocin in childbirth: what is it used for?
In hospital, oxytocin is used to induce and augment labour and to prevent and treat bleeding after the baby is born [1] [3]A [4]official. It is given into a vein or muscle, and contractions and the condition of the baby are closely monitored [4]official.
Oxytocin the hormone: what does it do in the body?
It contracts the uterus during labour and takes part in breastfeeding [1, 2]. In animals it plays a key role in attachment [10]C, but in humans the link with trust is uncertain [10].
Oxytocin nasal spray: does it work?
It has not been shown to. Large autism trials and a meta-analysis found no clear benefit from the nasal spray [5, 7]A. In mental disorders the overall effect was small and not statistically significant [8]A.
Oxytocin side effects: what is known?
In hospital use, possible harms include excessive uterine contractions and water intoxication [4]official. Short-term use of the nasal spray in research settings caused no harms that differed from placebo, but long-term use has been little studied [11].
Oxytocin dosage: how much did studies use?
In labour, the infusion starts at 0.5-1 mU/min according to the US label and is adjusted to the contractions [4]official. Nasal spray studies used 18-40 IU as a single dose or 32-48 IU a day [5, 6]A [11]. These are not dosing advice: Oxytocin dosage in studies.
How long does oxytocin work?
Briefly. Its half-life in plasma is about 1 to 6 minutes; given into a vein the effect subsides within an hour, and given into a muscle it lasts 2 to 3 hours [4]official.
Oxytocin in Finland: is the nasal spray legal?
Oxytocin is on the Finnish medicines list [15]regulator. In the EMA data, only oxytocin products given into a vein or muscle were recorded for Finland, not a nasal spray [13]regulator. According to Fimea, a product labelled "for research use only" is not intended for humans [18]regulator. This is not legal advice.
Oxytocin and doping: is it banned?
Oxytocin is not on the WADA 2026 Prohibited List. Class S0 (non-approved substances) does not apply to it, because it is an approved medicine [19]regulator. Athletes should still confirm with their national anti-doping organisation.
What are user experiences of oxytocin like?
User accounts of oxytocin have not been compiled on this site. Individual accounts are not research results.
Read the research yourself: sources
Every source opens the original publication or the regulator's page. The level shows what the source itself reports.
- Uvnäs-Moberg K. The physiology and pharmacology of oxytocin in labor and in the peripartum period. Am J Obstet Gynecol. 2024;230(3S):S740-S758. PMID 38462255 (review)
- Hermesch AC, Kernberg AS, Layoun VR, Caughey AB. Oxytocin: physiology, pharmacology, and clinical application for labor management. Am J Obstet Gynecol. 2024;230(3S):S729-S739. PMID 37460365 (review)
- Salati JA, Leathersich SJ, Williams MJ, Cuthbert A, Tolosa JE. Prophylactic oxytocin for the third stage of labour to prevent postpartum haemorrhage. Cochrane Database Syst Rev. 2019;4(4):CD001808. PMID 31032882 A
- U.S. National Library of Medicine, DailyMed. PITOCIN (oxytocin injection) label, Par Health USA (label version of May 2026). DailyMed (NIH) official
- Sikich L, Kolevzon A, King BH, et al. Intranasal Oxytocin in Children and Adolescents with Autism Spectrum Disorder. N Engl J Med. 2021;385(16):1462-1473. PMID 34644471 A
- Guastella AJ, Boulton KA, Whitehouse AJO, et al. The effect of oxytocin nasal spray on social interaction in young children with autism: a randomized clinical trial. Mol Psychiatry. 2023;28(2):834-842. PMID 36302965 A
- Fang G, Pan W, Li G, Ma L, Wei J. The Effect of Intranasal Oxytocin on Social Interaction in Adults and Children With Autism Spectrum Disorders: A Systematic Review and Meta-analysis of Randomized Controlled Trials. Alpha Psychiatry. 2026;27(4):45322. PMID 42694606 A
- Bonnieux J, Gumuchian ST, Harboun A, et al. Does intranasal oxytocin reduce symptoms of mental disorders? A meta-analysis of clinical trials. Neurosci Biobehav Rev. 2026;187:106749. PMID 42134427 A
- Leng G, Ludwig M. Intranasal Oxytocin: Myths and Delusions. Biol Psychiatry. 2016;79(3):243-250. PMID 26049207 (review)
- Nave G, Camerer C, McCullough M. Does Oxytocin Increase Trust in Humans? A Critical Review of Research. Perspect Psychol Sci. 2015;10(6):772-789. PMID 26581735 (review)
- MacDonald E, Dadds MR, Brennan JL, Williams K, Levy F, Cauchi AJ. A review of safety, side-effects and subjective reactions to intranasal oxytocin in human research. Psychoneuroendocrinology. 2011;36(8):1114-1126. PMID 21429671 (review)
- Cai Q, Feng L, Yap KZ. Systematic review and meta-analysis of reported adverse events of long-term intranasal oxytocin treatment for autism spectrum disorder. Psychiatry Clin Neurosci. 2018;72(3):140-151. PMID 29232031 A
- European Medicines Agency. Article 57 product data (EMA/518502/2018, data as of 21 Sep 2026): oxytocin entries, including Finland. EMA regulator
- European Medicines Agency. Medicine data (centrally authorised medicines, data set of 12 Oct 2026): no product with oxytocin. EMA regulator
- Finland. Lääkeluettelo (Fimea medicines list), 230/2025, annex 1. Finlex regulator
- Lambert P, McIntosh MP, Widmer M, et al. Oxytocin quality: evidence to support updated global recommendations on oxytocin for postpartum hemorrhage. J Pharm Policy Pract. 2020;13:14. PMID 32467764 (review)
- Torloni MR, Gomes Freitas C, Kartoglu UH, Metin Gülmezoglu A, Widmer M. Quality of oxytocin available in low- and middle-income countries: a systematic review of the literature. BJOG. 2016;123(13):2076-2086. PMID 27006180 (review)
- Fimea. Fimea varoittaa: älä käytä verkosta ostettuja pistettäviä peptidejä / Fimea warns: do not use injectable peptides purchased online. 29 Jun 2026. Fimea regulator
- World Anti-Doping Agency. 2026 Prohibited List. WADA regulator
Research sources checked 12 Oct 2026. Regulator and registry sources checked 12-13 Oct 2026.
Evidence levels: A = randomised human trial or meta-analysis · B = observational human study or case series · C = animal study · D = cell or laboratory study · E = not peer-reviewed · regulator = a regulator's assessment or decision, not research evidence. The marker official means official product information (summary of product characteristics or label); it is not research evidence. For a review, the level shows what kind of research the statement rests on. No level: statements that something has not been studied, reviews' interpretations, named hypotheses and the general rules in our certificate-of-analysis guide.
Content is general information about research, not medical advice. If you have symptoms, contact a healthcare professional.