Reviewed & approved by Dr. Nova Reyes · Last checked 2026-10-15. ← Back to Evidence Library

Oxytocin: what the evidence says

Legend: HUMAN data · ANIMAL / LAB data · UNKNOWN · UNVERIFIED: not yet confirmed against a primary source

Why the card says "No human data": the card shows the most cautious rating on this page. Anti-aging and long-term mood boosting, which the gray market also sells oxytocin for, have no human trials. Weight loss and autism social symptoms were tested in placebo-controlled trials, and the largest ones found no benefit (Tested, not shown). The hospital uses are rated Strong, but they need IV or injected oxytocin under medical supervision.

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What is it?

Oxytocin is a natural hormone. It acts on oxytocin receptors in the womb, breast and brain. It is chemically very close to vasopressin (the body's water-balance hormone). The two differ by only two amino acids, which is why large doses can make the body hold on to water. Its half-life (the time it takes for half of the drug to be cleared from the body) is about 1 to 6 minutes in the blood. ^R1

A rise in blood oxytocin levels after a nasal spray is a lab change, not a health benefit by itself. What matters is whether people get better, which is what the trials below test. ^R8

Where it's approved

Country / region	Product	Approved uses	How we checked
United States	Pitocin (oxytocin injection, USP), NDA 018261; generic oxytocin injection (e.g. NDA 018248, ANDA 200219)	Medically indicated labor induction; strengthening labor; adjunct in incomplete or inevitable abortion; contractions in the third stage of labor and control of postpartum bleeding. Not for elective induction. IV for labor, in hospital only	Drugs@FDA via openFDA and current label (effective May 6, 2026), checked Oct 15, 2026 R1, R2
United States	Syntocinon nasal spray, NDA 012285	Caution [UNVERIFIED: original indication; marketing status "Discontinued"]	Drugs@FDA via openFDA, checked Oct 15, 2026 R3
Other countries	Oxytocin injection is on the WHO standard for preventing postpartum bleeding and is used worldwide	Caution [UNVERIFIED: not checked country by country with each regulator]	Cochrane/WHO review R4

No regulator we checked has approved oxytocin, by any route, for social, mood, autism or weight uses.

The approved medicine: what its trials showed

Human Preventing heavy bleeding after birth: a 2025 Cochrane network meta-analysis (compares several treatments, including ones never tested against each other, by combining direct and indirect trial results; 122 trials, 121,931 women in 48 countries, screened for trustworthiness) found oxytocin and most other drugs that make the womb contract prevent bleeding of 500 mL or more compared with placebo or no treatment. Some combinations (ergometrine plus oxytocin, misoprostol plus oxytocin) may work better than oxytocin alone. Funded by the WHO-run HRP research programme. ^R4

Human Inducing labor: a 2009 Cochrane review (61 trials, 12,819 women) found that IV oxytocin, compared with waiting, meant fewer women had not delivered vaginally within 24 hours (8.4% vs 53.8%). It increased epidural use slightly, and prostaglandin gels did better on some outcomes. Review authors declared no conflicts. ^R5

Does it work for gray-market uses?

Human Weight loss: in a randomized, double-blind, placebo-controlled trial at Massachusetts General Hospital, 61 adults with obesity used an oxytocin or placebo nasal spray for 8 weeks. Weight change did not differ (0.20 vs 0.26 kg). Body fat, belly fat, liver fat and resting energy use did not improve either. People ate about 150 fewer calories at one test meal, but that did not turn into weight loss. An earlier one-day study in 25 healthy men also found less eating at one meal. A smaller meal in a lab is not proof of weight loss. ^{R6, R16}

Human Autism: the SOARS-B phase 2 trial (mid-size studies testing doses and early effects) gave 290 children and teens nasal oxytocin or placebo for 24 weeks. Social withdrawal scores improved the same in both groups (difference −0.2, P = 0.61, meaning the gap could easily be chance). In Japan, a 6-week trial in 106 men with autism missed its main goal; two secondary measures improved. ^{R7, R8}

Human Trust and bonding: a 2005 study in Nature reported that oxytocin raised trust in a money game. Two large preregistered replications (repeat studies whose methods were published before they started; 321 and 211 people) found no effect, and a pooled analysis of 532 people found any effect is too small to matter in lab studies. The 2020 replication hinted, in an unplanned analysis, that people low in trust might respond. A 2026 preregistered study of 359 men chosen for low trust then found trust rose about 15% (16.9% when pooled with 219 earlier low-trust participants). Two of its four authors also wrote the 2005 study or the 2020 replication. These are lab games, not real-life relationships. ^{R9–R11, R17}

Human Mental disorders: a 2026 meta-analysis (a study pooling the results) of 42 double-blind trials (1,922 people) found a small overall effect that could have been chance (non-significant), with a small signal in schizophrenia. ^R12

Unknown Anti-aging, "love hormone" mood boosting in healthy people over weeks: we found no trial. Rated No human data.

Who paid / conflicts: the weight trial (NIDDK and NIMH) and the SOARS-B autism trial (NICHD and other NIH institutes) were funded by the US National Institutes of Health. The Japanese autism trial was funded by the Japan Agency for Medical Research and Development (per Europe PMC grant record). Authors of the 2026 trust study declared no competing interests. Two Cochrane authors ran earlier bleeding-prevention trials for which Ferring and Novartis supplied drug; they were kept out of decisions on those trials. Caution [UNVERIFIED: funding of the 2020 trust replication not listed on PubMed or Europe PMC]

Is it safe?

• Human Approved hospital use (label): uterine overstimulation and rupture, water intoxication (dangerously low blood sodium) with seizures, coma and reported maternal death (with slow infusions over 24 hours), anaphylaxis, irregular heartbeat, high blood pressure, nausea and vomiting, and in the baby slow heart rate, jaundice, seizures, brain damage and death. That is why the label says it should be given by IV only with medical supervision in hospital. ^R1
• Human Nasal spray trials: adverse events (problems reported after use, which may or may not have been caused by the drug) were similar to placebo in SOARS-B and in the obesity trial, with no serious adverse events in the obesity trial. One man in the Japanese trial had temporary breast swelling (gynecomastia). ^R6–R8
• Dropouts vs placebo: in SOARS-B, 139 of 146 on oxytocin and 138 of 144 on placebo had at least one follow-up score. Caution [UNVERIFIED: dropout counts for the obesity trial not checked] ^R7
• Caution Because oxytocin acts like the water-balance hormone at high doses, repeated high-dose use outside hospital could in theory lower blood sodium. Caution [UNVERIFIED: no case report checked for nasal use]
• Unknown Long-term use in healthy people has not been studied. Oxytocin causes strong uterine contractions; outside a hospital it can harm a pregnancy. ^R1

Is it legal?

• FDA: approved only as an injection. Pitocin is a prescription drug. ^{R1, R2}
• Compounding (503A): oxytocin does not appear on FDA's 503A nominations list (May 14, 2026). Pharmacies may compound under 503A with a substance that has a USP monograph (an official quality standard). Oxytocin is a USP drug ("oxytocin injection, USP" on the label), so this route likely applies. Unknown This is our reading, not an FDA ruling. Caution [UNVERIFIED: USP monograph status not checked directly] ^R13
• Compounding (503B): listed in Category 1, "under evaluation," marked as a component of an FDA-approved drug (list updated Mar 21, 2025). ^R14
• Athletes: not named on WADA's 2026 Prohibited List. Because it is approved, the S0 "non-approved substances" catch-all likely doesn't apply. Unknown This is our reading, not a WADA ruling. ^R15

What's in the vial?

Pitocin and generic oxytocin injection are made under regulatory oversight. A gray-market oxytocin vial or nasal spray is not the approved product. It has no quality control and no guarantee of identity. It could contain the wrong compound, the wrong amount, impurities or bacterial toxins, or be fake (counterfeit). Oxytocin also breaks down easily if not kept cold Caution [UNVERIFIED: no stability source checked]. The trial results above don't transfer to it. We test retail vials blind under the Open Peptide Standard. See results at /tests/. A passing test covers one batch, tested on one date. It does not mean the compound itself is safe.

What do users report?

Self-report, not evidence.

We haven't summarized user reports for this peptide yet.

Study details

^{R4–R12, R16, R17} Human Human studies

Study	People	Route	Dose used (study arm, not a recommendation)	Follow-up	Reported	Limitations	Citation
Gallos 2025, Cochrane NMA	122 trials, 121,931 women	IV/IM	Various	Birth	Oxytocin effective vs placebo/no treatment for PPH ≥500 mL	Combinations may beat oxytocin alone	PMID 40237648
Alfirevic 2009, Cochrane	61 trials, 12,819 women	IV	Various	24 h+	Not delivered vaginally in 24 h: 8.4% vs 53.8% (RR 0.16)	Older trials	PMID 19821304
Plessow 2024	61 adults with obesity	Nasal	24 IU four times daily, 8 wk	8 wk	Weight 0.20 vs 0.26 kg (P=0.934); test meal −152 kcal	Short; small	PMID 38815173
Lawson 2015	25 healthy men, crossover	Nasal	24 IU once	Same day	Less caloric intake at one meal	Single dose	PMID 25865294
Sikich 2021, SOARS-B (phase 2)	290 children 3–17 with autism	Nasal	Target 48 IU daily	24 wk	ABC-mSW difference −0.2 (P=0.61); AEs similar	—	PMID 34644471
Yamasue 2020	106 men 18–48 with autism, Japan	Nasal	48 IU/day	6 wk	Primary (ADOS reciprocity) no difference; repetitive behavior better	Men only	PMID 29955161
Kosfeld 2005	Healthy men Caution [UNVERIFIED: n not in abstract]	Nasal	Single dose	Same day	More money transferred in trust game	Not replicated	PMID 15931222
Declerck 2020	321 healthy adults (preregistered; n per Kroll 2026)	Nasal	Single dose	Same day	No effect on trust (social-contact condition)	Lab game	PMID 32514040
Kroll 2026	211 healthy adults; pooled 532	Nasal	Single dose	Same day	No effect; pooled effect within a minimal range	Lab game	PMID 41880977
Vogt 2026	359 men low in trust	Nasal	Single dose	Same day	Trust ~15% higher	Selected subgroup; lab game	PMID 42561025
Bonnieux 2026, meta-analysis	42 RCTs, 1,922 people	Nasal	Various	Various	g = 0.17 (−0.05 to 0.38), non-significant	High heterogeneity	PMID 42134427

^{R1–R3, R13–R15} Regulatory sources (as of Oct 15, 2026)

• ^R1 Pitocin (oxytocin injection, USP) prescribing information, Par Health; DailyMed set ID 6d4b2c25-2e5d-49b5-93bc-2ae8a20916d1 (label effective May 6, 2026): https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=6d4b2c25-2e5d-49b5-93bc-2ae8a20916d1
• ^R2 Drugs@FDA, NDA 018261 (Pitocin; original approval listed Nov 19, 1980 as "new formulation or new manufacturer"), queried via openFDA Oct 15, 2026: https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm?event=overview.process&ApplNo=018261
• ^R3 Drugs@FDA, NDA 012285 (Syntocinon nasal solution, 40 USP units/mL, Discontinued), queried via openFDA Oct 15, 2026: https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm?event=overview.process&ApplNo=012285
• ^R13 FDA 503A nominations list (May 14, 2026): https://www.fda.gov/media/94155/download
• ^R14 FDA 503B nominations list (Mar 21, 2025), Category 1: https://www.fda.gov/media/94164/download
• ^R15 WADA 2026 Prohibited List: https://www.wada-ama.org/en/resources/world-anti-doping-code-and-international-standards/prohibited-list

Full reference list (PMIDs verified on PubMed, Oct 15, 2026)

• ^R4 Gallos ID, et al. Cochrane Database Syst Rev. 2025. doi:10.1002/14651858.CD011689.pub4. PMID 40237648. Funded by HRP (WHO-executed programme). Two authors ran eligible trials with drug supplied by Ferring and Novartis; excluded from decisions on them.
• ^R5 Alfirevic Z, et al. Cochrane Database Syst Rev. 2009. doi:10.1002/14651858.CD003246.pub2. PMID 19821304. No conflicts known.
• ^R6 Plessow F, et al. NEJM Evid. 2024;3(5):EVIDoa2300349. doi:10.1056/EVIDoa2300349. PMID 38815173. Funded by NIDDK and NIMH.
• ^R7 Sikich L, et al. N Engl J Med. 2021;385(16):1462-73. doi:10.1056/NEJMoa2103583. PMID 34644471. Funded by NICHD (with NCATS and NIGMS grants also listed).
• ^R8 Yamasue H, et al. Mol Psychiatry. 2020;25(8):1849-58. doi:10.1038/s41380-018-0097-2. PMID 29955161. Funded by AMED (Japan).
• ^R9 Declerck CH, et al. Nat Hum Behav. 2020. doi:10.1038/s41562-020-0878-x. PMID 32514040.
• ^R10 Kroll CF, et al. Cortex. 2026;198:208-33. doi:10.1016/j.cortex.2026.03.006. PMID 41880977. One author consults for P1vital (unrelated).
• ^R11 Vogt B, et al. Proc Natl Acad Sci U S A. 2026. doi:10.1073/pnas.2602655123. PMID 42561025. No competing interests declared. Authors include Fehr (Kosfeld 2005) and Declerck (2020 replication).
• ^R12 Bonnieux J, et al. Neurosci Biobehav Rev. 2026;187:106749. doi:10.1016/j.neubiorev.2026.106749. PMID 42134427.
• ^R16 Lawson EA, et al. Obesity (Silver Spring). 2015;23(5):950-6. doi:10.1002/oby.21069. PMID 25865294.
• ^R17 Kosfeld M, et al. Nature. 2005. doi:10.1038/nature03701. PMID 15931222.

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Disclaimer

This page is for education and harm reduction. It is not medical advice and not a recommendation to use oxytocin outside approved medical care. Please talk to a clinician you trust, especially if you are pregnant or breastfeeding, have heart or kidney problems, or are a tested athlete. Seek care right away for a serious reaction (for example confusion, seizures or severe headache), and report it to FDA MedWatch (https://www.fda.gov/safety/medwatch) or your national regulator.