Oxytocin: Nonapeptide Hormone Research Data
A conservative review of oxytocin: its chemistry and receptor, the approved childbirth use, the trust and bonding research that did not replicate, the autism and obesity trials, and where regulators stand in 2026.
Update History ▾
Research-use-only framing applied throughout in line with Remy editorial standards.
Oxytocin is a nine-amino-acid hormone with one firmly established medical role, in childbirth: approved injections start or strengthen labour contractions and control bleeding after delivery.[1][2] Its reputation as a “bonding” or “trust” molecule rests on animal studies and small human experiments; the best-known human result, on trust, did not hold up in larger preregistered studies.[3][4][5] Nasal oxytocin did not improve social behaviour in a trial of 290 children and adolescents with autism, or reduce weight in an obesity trial.[6][7]
No UAE registration of an oxytocin pre-filled research pen as a medicine was found; the approved oxytocin injection used in childbirth is a separate product. Remy Research sells the Genovare pen for in-vitro laboratory research only, not for human or veterinary use.
What Is Oxytocin?
Oxytocin is a nonapeptide, Cys-Tyr-Ile-Gln-Asn-Cys-Pro-Leu-Gly, ending in a glycine amide, with a disulfide bond joining the two cysteines into a ring. It is made as part of a larger precursor together with its carrier protein, neurophysin 1.[8] PubChem lists it as C43H66N12O12S2, with a molecular weight of about 1,007.2 g/mol and PubChem CID 439302.[9]
Vincent du Vigneaud’s group proposed its sequence in 1953, and he received the 1955 Nobel Prize in Chemistry for the first synthesis of a polypeptide hormone.[10][11] The approved US injection is made synthetically to avoid possible contamination with the closely related hormone vasopressin.[1]
How Oxytocin Works
Oxytocin is made mainly in large neurons of the hypothalamus and released into the blood from the posterior pituitary, in response to suckling, labour and some kinds of stress. Those neurons also project widely within the brain, and the uterus, placenta, testis and heart make oxytocin too. Its receptor is a G-protein-coupled receptor that signals mainly through Gq and phospholipase C.[12]
| Role | What was reported | Evidence type |
|---|---|---|
| Labour | Approved injections start or strengthen contractions and control bleeding after delivery | Approved use, trials |
| Milk ejection | Mice without oxytocin give birth normally but cannot nurse | Animal (knockout) |
| Pair bonding | Oxytocin signalling linked to partner preference in female prairie voles; voles without the receptor still bond | Animal |
| Trust in humans | An early trust result did not replicate in larger preregistered studies | Human experiments |
| Water balance | Intrinsic antidiuretic effect noted on the approved label | Approved label |
Gene-deletion work has narrowed oxytocin’s essential roles. Mice that cannot make oxytocin mate, give birth and care for their young normally, but their pups die unless oxytocin is given to restore milk ejection.[13]
The Approved Use: Childbirth
In the US, oxytocin injection is approved before delivery to start or improve uterine contractions when there is a medical reason, and after delivery to produce contractions in the third stage of labour and to control bleeding. The label states it is not indicated for elective induction of labour.[1] Oxytocin has been on the WHO Model List of Essential Medicines since 1977, for postpartum haemorrhage.[14]
The evidence for prevention is real but modest in quality. A 2019 Cochrane review found that preventive oxytocin, compared with no uterotonic or placebo, roughly halved the risk of losing 500 mL of blood or more (risk ratio 0.51; 95% CI 0.37–0.72; 6 studies, 4,162 women; low-quality evidence).[2] In the WHO CHAMPION trial of 29,645 women, heat-stable carbetocin, a longer-acting analogue, was non-inferior to oxytocin for blood loss of at least 500 mL or the need for another uterotonic (14.5% against 14.4%).[15]
The Social-Behaviour Research: What Held Up
- Prairie voles, 1995. In monogamous female prairie voles, oxytocin infusions produced a partner preference without mating, and an oxytocin blocker prevented the preference that normally follows mating.[16]
- Prairie voles, 2023. Voles engineered to lack the oxytocin receptor still formed partner bonds, gave birth and raised their young.[17]
- Trust, 2005. A Nature study reported that nasal oxytocin increased trust in an economic game.[3]
- Trust replications, 2020 and 2026. A preregistered replication with more than 95% power found no effect in the original condition, and a 2026 registered report of 211 people, pooled with it to 532, found no evidence that oxytocin increases trusting behaviour.[4][5]
Two 2016 reviews give reasons for caution. One concluded that nasal oxytocin studies are generally underpowered and that most published positive findings are probably not true effects.[18] The other noted that very little nasally applied oxytocin appears to reach the cerebrospinal fluid while blood levels rise far above normal, and that many oxytocin measurements used discredited methods.[19] A 2020 monkey study did detect labelled oxytocin in some brain regions after nasal delivery, so the question of brain entry is still open.[20]
Clinical Trials Outside Childbirth
- Autism, 2021. SOARS-B, a 24-week placebo-controlled trial in 290 children and adolescents, found no difference in social withdrawal scores (change −3.7 with oxytocin against −3.5 with placebo; P=0.61). Adverse events were similar in both groups.[6]
- Obesity, 2024. In an 8-week placebo-controlled trial of 61 adults, nasal oxytocin did not change body weight (a change of 0.20 kg against 0.26 kg on placebo), body fat or energy expenditure. People ate less at one test meal, and there were no serious adverse events.[7]
No use of oxytocin outside obstetrics is approved by FDA, and the only nasal oxytocin product in Drugs@FDA is listed as discontinued.[21]
What Has Been Published on Safety
- The approved label. It lists uterine overstimulation and, because oxytocin has an intrinsic antidiuretic effect, the possibility of water intoxication, especially with continuous infusion. It also notes maternal and fetal deaths reported in association with injected oxytocic drugs used to induce or augment labour.[1]
- Half-life. The label gives a plasma half-life of about 1 to 6 minutes.[1]
- Nasal trials. The autism and obesity trials reported adverse events similar to placebo, but each lasted 24 weeks or less.[6][7]
There are no long-term safety data for oxytocin outside obstetric care.
Regulatory Status in 2026
- United States. Oxytocin injection (Pitocin and generic versions) is FDA-approved for the obstetric uses above. The Syntocinon nasal solution is listed as discontinued, and no other nasal oxytocin product appears in Drugs@FDA.[1][21]
- WHO. Oxytocin is an essential medicine for postpartum haemorrhage.[14]
- UAE. No UAE registration of an oxytocin pre-filled research pen as a medicine was found; oxytocin injection, the obstetric medicine described above, is a separate product. Remy Research sells the Genovare pen for in-vitro laboratory research only, not for human or veterinary use.
- Sport. Oxytocin is not named on WADA’s 2026 or 2027 Prohibited List, and as an approved medicine it falls outside the S0 clause for unapproved substances.[22][23]
What the Oxytocin Literature Does Not Yet Give You
- A replicated social effect in people. The best-known trust result failed in larger preregistered studies.[4][5]
- A positive large trial outside childbirth. The largest autism and obesity trials were negative on their main outcomes.[6][7]
- Settled brain delivery. How much nasal oxytocin reaches the human brain is still debated.[19][20]
- A mass-to-activity link for research material. Approved injections are standardised by their oxytocic activity, not by weight, so a milligram label says nothing about activity without verified potency data.[1]
These gaps are not arguments against studying oxytocin. They are arguments against overselling it.
Where Oxytocin Fits in an RUO Research Catalog
For research use, oxytocin belongs with the neuropeptide hormone research tools: a defined receptor agonist for cell-culture and animal-model work on uterine, lactation and social-behaviour signalling. Remy Research sells the Genovare Oxytocin 40mg AQ pen; Genovare is the brand and manufacturer. The pen is labelled 40mg by mass, which cannot be compared with approved products standardised by activity.
No independent batch report has been published for this pen, so its sequence, identity, quantity and activity are unverified; its product page lists its testing status as “Independent testing not supplied”. Every report Remy Research has published is in the lab results library. The pen is supplied for in-vitro laboratory research only, not for human or veterinary use, and is not framed for treatment.
For researchers reading this page as a starting point, the most useful adjacent references on this site are the HCG research review, the PT-141 melanocortin review, the COA and HPLC purity guide, and the pen and vial comparison.
Our Research Standards
This article prioritizes primary literature, preregistered replications, the approved prescribing information and regulator records, and keeps approved, animal and experimental human evidence apart. No therapeutic, human-use, or veterinary-use claim is made here. Read our editorial policy →
Oxytocin Research FAQ
What is oxytocin?
Is oxytocin FDA-approved?
Yes, as an injection for obstetric use: to start or strengthen labour contractions when there is a medical reason, and to control bleeding after delivery. It is not indicated for elective induction, and no use outside obstetrics is approved.[1]
Is there an approved oxytocin nasal spray?
Not in the US today. The only nasal oxytocin product listed in Drugs@FDA, Syntocinon nasal solution, is discontinued; current approved products are injections.[21]
Does oxytocin increase trust or bonding in people?
Does oxytocin help autism?
The largest trial says no. SOARS-B, with 290 children and adolescents treated for 24 weeks, found no difference from placebo in social withdrawal scores.[6]
Does oxytocin cause weight loss?
Not in the best trial so far. In 61 adults with obesity, 8 weeks of nasal oxytocin did not change body weight, body fat or energy expenditure compared with placebo, although intake at one test meal was lower.[7]
Is oxytocin on the WADA Prohibited List?
Has the Genovare oxytocin pen been independently tested?
No independent batch report has been published for this pen, so its sequence, identity, quantity and activity are unverified. Its product page states “Independent testing not supplied”, and every report Remy Research has published is listed in the lab results library.
Sources
- Pitocin (oxytocin injection, USP) prescribing information, DailyMed, updated May 6, 2026. dailymed.nlm.nih.gov ↩
- Salati JA, Leathersich SJ, Williams MJ, et al. Prophylactic oxytocin for the third stage of labour to prevent postpartum haemorrhage. Cochrane Database Syst Rev. 2019;4(4):CD001808. doi: 10.1002/14651858.CD001808.pub3 · PMID: 31032882 ↩
- Kosfeld M, Heinrichs M, Zak PJ, et al. Oxytocin increases trust in humans. Nature. 2005;435(7042):673-676. doi: 10.1038/nature03701 · PMID: 15931222 ↩
- Declerck CH, Boone C, Pauwels L, et al. A registered replication study on oxytocin and trust. Nat Hum Behav. 2020;4(6):646-655. doi: 10.1038/s41562-020-0878-x · PMID: 32514040 ↩
- Kroll CF, Schruers KRJ, Viechtbauer W, et al. Absence of a meaningful effect of intranasal oxytocin on trusting behavior: a registered report with pooled equivalence testing. Cortex. 2026;198:208-233. doi: 10.1016/j.cortex.2026.03.006 · PMID: 41880977 ↩
- 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. doi: 10.1056/NEJMoa2103583 · PMID: 34644471 ↩
- Plessow F, Kerem L, Wronski ML, et al. Intranasal Oxytocin for Obesity. NEJM Evid. 2024;3(5):EVIDoa2300349. doi: 10.1056/EVIDoa2300349 · PMID: 38815173 ↩
- UniProt Consortium. UniProtKB P01178, oxytocin-neurophysin 1 proprotein (human): oxytocin CYIQNCPLG with a Cys1–Cys6 disulfide and a C-terminal glycine amide. uniprot.org/uniprotkb/P01178 ↩
- National Center for Biotechnology Information. PubChem Compound Summary for CID 439302, oxytocin (C43H66N12O12S2, 1007.2 g/mol). pubchem.ncbi.nlm.nih.gov/compound/439302 ↩
- du Vigneaud V, Ressler C, Trippett S. The sequence of amino acids in oxytocin, with a proposal for the structure of oxytocin. J Biol Chem. 1953;205(2):949-957. PMID: 13129273 ↩
- NobelPrize.org. The Nobel Prize in Chemistry 1955: Vincent du Vigneaud, "for his work on biochemically important sulphur compounds, especially for the first synthesis of a polypeptide hormone". nobelprize.org ↩
- Gimpl G, Fahrenholz F. The oxytocin receptor system: structure, function, and regulation. Physiol Rev. 2001;81(2):629-683. doi: 10.1152/physrev.2001.81.2.629 · PMID: 11274341 ↩
- Nishimori K, Young LJ, Guo Q, et al. Oxytocin is required for nursing but is not essential for parturition or reproductive behavior. Proc Natl Acad Sci U S A. 1996;93(21):11699-11704. doi: 10.1073/pnas.93.21.11699 · PMID: 8876199 ↩
- World Health Organization. Electronic Essential Medicines List: oxytocin, first added in 1977, uterotonics, for postpartum haemorrhage. list.essentialmeds.org ↩
- Widmer M, Piaggio G, Nguyen TMH, et al; WHO CHAMPION Trial Group. Heat-Stable Carbetocin versus Oxytocin to Prevent Hemorrhage after Vaginal Birth. N Engl J Med. 2018;379(8):743-752. doi: 10.1056/NEJMoa1805489 · PMID: 29949473 ↩
- Insel TR, Hulihan TJ. A gender-specific mechanism for pair bonding: oxytocin and partner preference formation in monogamous voles. Behav Neurosci. 1995;109(4):782-789. doi: 10.1037//0735-7044.109.4.782 · PMID: 7576222 ↩
- Berendzen KM, Sharma R, Mandujano MA, et al. Oxytocin receptor is not required for social attachment in prairie voles. Neuron. 2023;111(6):787-796.e4. doi: 10.1016/j.neuron.2022.12.011 · PMID: 36708707 ↩
- Walum H, Waldman ID, Young LJ. Statistical and Methodological Considerations for the Interpretation of Intranasal Oxytocin Studies. Biol Psychiatry. 2016;79(3):251-257. doi: 10.1016/j.biopsych.2015.06.016 · PMID: 26210057 ↩
- Leng G, Ludwig M. Intranasal Oxytocin: Myths and Delusions. Biol Psychiatry. 2016;79(3):243-250. doi: 10.1016/j.biopsych.2015.05.003 · PMID: 26049207 ↩
- Lee MR, Shnitko TA, Blue SW, et al. Labeled oxytocin administered via the intranasal route reaches the brain in rhesus macaques. Nat Commun. 2020;11(1):2783. doi: 10.1038/s41467-020-15942-1 · PMID: 32494001 ↩
- U.S. Food and Drug Administration. Drugs@FDA, NDA 012285: Syntocinon (oxytocin) nasal solution, marketing status "Discontinued"; the other oxytocin applications in Drugs@FDA are injections. accessdata.fda.gov ↩
- World Anti-Doping Agency. 2026 Prohibited List (oxytocin is not named; class S0 covers substances with no current governmental approval for human therapeutic use). wada-ama.org ↩
- World Anti-Doping Agency. 2027 Prohibited List, approved September 10, 2026 and in force from January 1, 2027 (oxytocin is not named). wada-ama.org ↩
For catalog details, see the Genovare Oxytocin 40mg AQ pen and the lab results library. For editorial standards, continue to the research standards page.