{"id":"oxytocin","name":"Oxytocin (intranasal)","aliases":["Pitocin","Syntocinon","the bonding hormone","intranasal oxytocin"],"url":"https://lyoresearch.com/compounds/oxytocin","class":{"id":"reproductive-hormones","name":"Reproductive and neuroendocrine hormones","url":"https://lyoresearch.com/classes/reproductive-hormones"},"summary":"Oxytocin is a natural nine-amino-acid hormone, licensed for decades as an injection to induce labour and control bleeding. The compound sold and discussed in the peptide world is intranasal oxytocin, promoted for bonding, appetite and social behaviour. Here the evidence is largely negative: the largest randomised trial in autism found no benefit, and a randomised obesity trial found no weight loss. It is well tolerated, but the popular claims rest on small early studies that the big trials did not confirm.","overall_grade":"C","overall_grade_meaning":"weak human evidence","human_trials":"Many RCTs (intranasal mostly null)","regulatory_status":"Approved (Rx) as injection; intranasal use unlicensed","molecule":{"formula":"C43H66N12O12S2","molecular_weight":"1007.2","cas":"50-56-6","pubchem_cid":439302,"note":null},"pharmacokinetics":{"basis":"label","route":"Intravenous infusion (labour) or intramuscular injection (postpartum)","half_life":"About 1-6 minutes","licensed_regimen":"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","product":"Pitocin","source":{"title":"Pitocin prescribing information (DailyMed)","url":"https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=969d5b35-0add-4c23-9605-6a5b6ab65c95"}},"outcomes":[{"outcome":"Social function in autism","grade":"B","grade_meaning":"probable, not settled","effect_size":"not measurable","adverse":false,"human_studies":"1 large phase 2 RCT (n=290)","evidence":"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.","references":[{"citation":"Sikich L, et al. Intranasal oxytocin in children and adolescents with autism spectrum disorder (SOARS-B).","where":"N Engl J Med, 2021;385:1462–1473","url":"https://pubmed.ncbi.nlm.nih.gov/34644471/"}],"verbatim":{"text":"The least-squares mean change from baseline in the ABC-mSW score (primary outcome) was -3.7 in the oxytocin group and -3.5 in the placebo group (least-squares mean difference, -0.2; 95% confidence interval, -1.5 to 1.0; P = 0.61).","citation":"Sikich L, et al. Intranasal oxytocin in children and adolescents with autism spectrum disorder (SOARS-B).","url":"https://pubmed.ncbi.nlm.nih.gov/34644471/"}},{"outcome":"Weight loss in obesity","grade":"C","grade_meaning":"weak human evidence","effect_size":"not measurable","adverse":false,"human_studies":"1 RCT (n=61)","evidence":"Eight weeks of intranasal oxytocin four times daily produced no weight change versus placebo, though it modestly reduced intake at a single test meal.","references":[{"citation":"Plessow F, et al. Intranasal oxytocin for obesity.","where":"NEJM Evidence, 2024;3:EVIDoa2300349","url":"https://pubmed.ncbi.nlm.nih.gov/38815173/"}],"verbatim":{"text":"There was no difference in body weight change from baseline to week 8 between oxytocin and placebo groups (0.20 vs. 0.26 kg; P=0.934).","citation":"Plessow F, et al. Intranasal oxytocin for obesity.","url":"https://pubmed.ncbi.nlm.nih.gov/38815173/"}},{"outcome":"Appetite / caloric intake (acute)","grade":"C","grade_meaning":"weak human evidence","effect_size":"small","adverse":false,"human_studies":"Small crossover studies","evidence":"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.","references":[{"citation":"Plessow F, et al. Intranasal oxytocin for obesity.","where":"NEJM Evidence, 2024;3:EVIDoa2300349","url":"https://pubmed.ncbi.nlm.nih.gov/38815173/"}],"verbatim":{"text":"Oxytocin compared with placebo was associated with reduced caloric intake at the test meal (-31.4 vs. 120.6 kcal; difference [95% confidence interval], -152.0 kcal [-302.3 to -1.7]).","citation":"Plessow F, et al. Intranasal oxytocin for obesity.","url":"https://pubmed.ncbi.nlm.nih.gov/38815173/"}},{"outcome":"Safety (intranasal, short-term)","grade":"B","grade_meaning":"probable, not settled","effect_size":"small","adverse":true,"human_studies":"Multiple RCTs","evidence":"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.","references":[{"citation":"Sikich L, et al. Intranasal oxytocin in children and adolescents with autism spectrum disorder (SOARS-B).","where":"N Engl J Med, 2021;385:1462–1473","url":"https://pubmed.ncbi.nlm.nih.gov/34644471/"}],"verbatim":{"text":"The incidence and severity of adverse events were similar in the two groups.","citation":"Sikich L, et al. Intranasal oxytocin in children and adolescents with autism spectrum disorder (SOARS-B).","url":"https://pubmed.ncbi.nlm.nih.gov/34644471/"}}],"regions":[{"region":"European Union","status":"Approved as injection; nasal use unlicensed","note":"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."},{"region":"United States","status":"Approved as injection (Pitocin)","note":"The injection is FDA-approved for obstetric indications. Intranasal oxytocin is not FDA-approved and is sold via compounding pharmacies and the grey market."},{"region":"United Kingdom","status":"Licensed as injection","note":"Syntocinon injection is MHRA-licensed for obstetric use; other routes and indications are unlicensed."},{"region":"Australia","status":"Registered as injection","note":"Injectable oxytocin is on the ARTG for obstetric use; intranasal products are not registered for the marketed 'wellness' uses."},{"region":"Canada","status":"Authorised as injection","note":"Injectable oxytocin carries a DIN; nasal 'wellness' products do not."},{"region":"Sport (WADA)","status":"Not prohibited","note":"Not on the 2026 Prohibited List."}],"faq":[{"q":"Does oxytocin nasal spray help autism?","a":"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."},{"q":"Will oxytocin help me lose weight?","a":"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."},{"q":"Is the injection different from the spray?","a":"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."}],"references":[{"cite":"Sikich L, et al. Intranasal oxytocin in children and adolescents with autism spectrum disorder (SOARS-B).","where":"N Engl J Med, 2021;385:1462–1473","url":"https://pubmed.ncbi.nlm.nih.gov/34644471/","note":"290 participants, 24 weeks; primary and secondary outcomes null."},{"cite":"Plessow F, et al. Intranasal oxytocin for obesity.","where":"NEJM Evidence, 2024;3:EVIDoa2300349","url":"https://pubmed.ncbi.nlm.nih.gov/38815173/","note":"61 adults, 8 weeks; no weight change, reduced single-meal intake."}],"last_reviewed":"2026-09-03","literature_searched_to":"2026-09-03","changelog":[{"date":"2026-09-03","note":"Initial publication. Grades reflect large, well-conducted but mostly null intranasal trials."}],"license":"CC BY 4.0 — cite as “LYO Research” with a link.","methodology":"https://lyoresearch.com/methodology"}