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Cited by 615Neuroendocrine regulation and behaviorOlfactory and Sensory Function StudiesStress Responses and Cortisol

Intranasal Oxytocin: Myths and Delusions

Open access
Leng, Gareth, Ludwig, Mike·2016·Biological Psychiatry
DOI 10.1016/j.biopsych.2015.05.003
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Abstract

Despite widespread reports that intranasal application of oxytocin has a variety of behavioral effects, very little of the huge amounts applied intranasally appears to reach the cerebrospinal fluid. However, peripheral concentrations are increased to supraphysiologic levels, with likely effects on diverse targets including the gastrointestinal tract, heart, and reproductive tract. The wish to believe in the effectiveness of intranasal oxytocin appears to be widespread and needs to be guarded against with scepticism and rigor. Preregistering trials, declaring primary and secondary outcomes in advance, specifying the statistical methods to be applied, and making all data openly available should minimize problems of publication bias and questionable post hoc analyses. Effects of intranasal oxytocin also need proper dose-response studies, and such studies need to include control subjects for peripheral effects, by administering oxytocin peripherally and by blocking peripheral actions with antagonists. Reports in the literature of oxytocin measurements include many that have been made with discredited methodology. Claims that peripheral measurements of oxytocin reflect central release are questionable at best.

AI snapshot

Written from the paper’s full text.

TL;DR

The review argues that despite widespread reports of behavioral effects, very little intranasally applied oxytocin reaches CSF while peripheral concentrations rise to supraphysiological levels. It contends that many findings are undermined by poor oxytocin assays, publication bias, and questionable analyses, and calls for preregistration, dose-response studies, and controls for peripheral effects.

Key findings

  • Across seven studies of intranasal oxytocin/vasopressin, at most 0.005% of the intranasal dose reached CSF within an hour; two studies found no rise. Intranasal doses exceeded pituitary content as a bolus, yet produced only modest CSF increases.
  • Intranasal administration produced large, prolonged rises in circulating oxytocin: four studies achieved plasma oxytocin >20 pg/ml from basal <5 pg/ml; Modi et al. reported a 100-fold increase in macaques to >300 pg/ml, and Dal Monte et al. reported a rise to 80 pg/ml after nasal spray but no significant rise with a nebuliser.
  • Many plasma oxytocin measurements used unextracted ELISA yielding values >300 pg/ml; three studies comparing ELISA with and without extraction on the same samples reported no correlations. Peripheral measurements are questionable as reflections of central release.
  • Recent trials with clear primary outcomes showed no effect of intranasal oxytocin in schizophrenia, healthy volunteers, early psychosis, Prader-Willi syndrome, MDMA users, or youths with autism spectrum disorders; in one autism study, caregivers who believed their children received oxytocin reported greater improvements than those who believed their child received placebo.

Methods

  • Critical/narrative review of published animal and human literature on intranasal oxytocin pharmacokinetics, CSF and plasma measurements, behavioral effects, and publication bias; no new experimental data are reported.
  • Synthesizes seven studies measuring CSF oxytocin or vasopressin after intranasal administration and compares reported CSF/plasma concentrations and estimated percentages of dose reaching CSF.
  • Discusses assay validity, including extracted versus unextracted plasma measurements, radioimmunoassay, LC/mass spectrometry, and ELISA, and reviews trial-design issues such as preregistration and primary outcome reporting.

Limitations

  • The authors state that it is not impossible that enormous intranasal doses achieve biologically significant brain elevations, and that intranasally applied oxytocin might penetrate some brain regions yet not enter CSF.
  • They state that effects of intranasal oxytocin need proper dose-response studies and controls for peripheral effects, by administering oxytocin peripherally and by blocking peripheral actions with antagonists.
  • Evident from the text: this is a narrative critical review, not a systematic review or meta-analysis, and its conclusions depend on cited studies with heterogeneous methods and measurements.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1016/j.biopsych.2015.05.003

Cites

111 of 111 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

30 of 88 cited sources checked · 13 supported · 3 flagged · accuracy not yet measured

  • Premisecitation

    Comparison of CSF neurophysin and oxytocin levels suggests that only about 5% of oxytocin released in the rat brain reaches the CSF.

    “Comparing CSF levels of neurophysin and oxytocin suggests that only ~5% of the oxytocin that is released in the rat brain reaches the CSF (1).”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [1] Leng, 2008, Neurotransmitters and peptides: Whispered secrets and public announcements, J Physiol source

      The paper’s Abstract compares CSF oxytocin with co-released neurophysin and estimates that about 80 oxytocin vesicles per second reach the CSF, versus about 4,000 released centrally. That implies roughly 2%, not the cited sentence’s ~5%. (LLM, conf=0.88)

      Checked by a reasoning model — may be wrong.

      Experimental — accuracy not yet measured
  • Premisecitation

    In two macaques given 25 IU intranasal oxytocin, CSF oxytocin increased from about 20 to about 50 pg/ml at 35 minutes.

    “Chang et al. gave 25IU oxytocin to two macaques, and reported a rise in CSF from ~20 to ~50pg/ml at 35min (24).”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [24] Chang, 2012, Inhaled oxytocin amplifies both vicarious reinforcement and self reinforcement in rhesus macaques (Macaca mulatta), Proc Natl Acad Sci U S A source

      The Results say two male macaques received 25 IU intranasal oxytocin, and the CSF OT Protocol says CSF was sampled on average 35 minutes after inhalation began. The Methods report an approximately 2.5-fold rise in CSF oxytocin, consistent with 20 to 50 pg/mL, but our copy does not state those absolute concentrations. (LLM, conf=0.84)

      Experimental — accuracy not yet measured
  • Premisecitation

    In MDMA users, CSF and plasma oxytocin concentrations are uncorrelated.

    “or in MDMA users (92)”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [92] Kuypers, 2014, No evidence that MDMA-induced enhancement of emotional empathy is related to peripheral oxytocin levels or 5-HT1a receptor activation, PloS One source

      The Discussion (page unavailable) says plasma and CSF oxytocin concentrations do not correlate when sampled at the same time, citing another study for that observation. But this paper measured serum oxytocin in MDMA users, not CSF oxytocin, so it does not establish that the two concentrations are uncorrelated in MDMA users. (LLM, conf=0.86)

      Experimental — accuracy not yet measured
  • Premisecitation

    Many papers have used an ELISA on unextracted plasma and obtained oxytocin values above 300 pg/ml.

    “However, many papers have used an ELISA on unextracted plasma, yielding values of >300pg/ml (59)(60)(61)(62)(63)(64)(65).”
    Quote in the paperSubstantial claim2 of 3 sources checked
    • cites [59] Feldman, 2011, Maternal and paternal plasma, salivary, and urinary oxytocin and parent-infant synchrony: Considering stress and affiliation components of human bonding, Dev Sci source
    • cites [60] Zhong, 2012, U-shaped relation between plasma oxytocin levels and behavior in the trust game, PloS One source
    • cites [61] Rubin, 2014, Reduced levels of vasopressin and reduced behavioral modulation of oxytocin in psychotic disorders, Schizophr Bull source

      The Measures section (page unavailable) says this study used an enzyme immunoassay on unextracted plasma and reran oxytocin samples above 2,000 pg/ml, supporting the method and values above 300 pg/ml for this study. It does not establish that many papers used the method and obtained such values. (LLM, conf=0.88)

      Experimental — accuracy not yet measured
  • Premisecitation

    A report that intranasal oxytocin increased trust drove much of the subsequent interest in it.

    “Much of the interest in intranasal oxytocin followed a report that it enhanced trust (96)”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [96] Kosfeld, 2005, Oxytocin increases trust in humans, Nature source
  • May combine two claims. 39
  • Classified as probably not a substantial claim. 5

  • May combine two claims.

    Premisecitation

    Robertson et al. found that two vasopressin radioimmunoassays on unextracted plasma yielded values at least two orders of magnitude higher than those inferred from other evidence, and these values did not fluctuate in parallel with endogenous authentic vasopressin.

    “Robertson et al. showed that two radioimmunoassays for vasopressin yielded measurements in unextracted plasma that were at least two orders of magnitude greater than those inferred from other evidence, and which did not fluctuate in parallel with endogenous authentic vasopressin (33,58).”
    Quote in the paperSubstantial claim1 of 2 sources checked
    • cites [33] Robertson, 1970, Immunoassay of plasma vasopressin in man, Proc Natl Acad Sci U S A source
    • cites [58] Robertson, 1973, Development and clinical application of a new method for the radioimmunoassay of arginine vasopressin in human plasma, J Clin Invest source

      Split into 2 atoms — 0 confirmed, 1 partially supported, 1 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.

      Checked by a reasoning model — may be wrong.

      Experimental — accuracy not yet measured

  • May combine two claims.

    Premisecitation

    Recent trials found no effect of intranasal oxytocin in schizophrenia patients or healthy volunteers.

    “They show no effect of intranasal oxytocin on patients with schizophrenia or healthy volunteers (102,103)”
    Quote in the paperSubstantial claim1 of 2 sources checked
    • cites [102] Horta de Macedo, 2014, Oxytocin does not improve performance of patients with schizophrenia and healthy volunteers in a facial emotion matching task, Psychiatry Res source
    • cites [103] Woolley, 2014, Oxytocin administration enhances controlled social cognition in patients with schizophrenia, Psychoneuroendocrinology source

      The Abstract Results report that intranasal oxytocin significantly improved controlled social cognition in patients with schizophrenia, contrary to the claimed lack of effect. The Discussion (§4.3) also reports improved performance on difficult RMET items in healthy participants, although effects on other aspects of their social cognition were limited. (LLM, conf=0.91)

      Checked by a reasoning model — may be wrong.

      Experimental — accuracy not yet measured
    • Rests on an assumption: The recent trials cited as showing no effect had sufficient statistical power to detect effects of intranasal oxytocin.

  • May combine two claims.

    Premisecitation

    In macaques given 48 IU intranasal oxytocin, CSF oxytocin rose from about 35 to about 90 pg/ml at 40 minutes; assuming a 40 ml CSF volume, the additional amount was 2.2 ng, or 0.002% of the dose.

    “Dal Monte et al. gave 48IU oxytocin (~10µg/kg body weight) intranasally to macaques, using either a spray or nebuliser (23).These increased CSF oxytocin from ~35pg/ml to ~90pg/ml after 40min.On the (very) conservative assumption that the CSF/ECF volume in the macaque is 40ml, then the additional content at this time is 2.2ng, 0.002% of the administered dose.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [23] Dal Monte, 2014, CSF and blood oxytocin concentration changes following intranasal delivery in macaque, PloS One source

      The Methods report 48 IU intranasal oxytocin given to macaques by spray or nebulizer, and the Results report a significant CSF increase at 40 minutes. Our copy does not state the approximate 35-to-90 pg/ml values; Figure 1’s caption identifies the measurements but gives no numbers. The 40 ml assumption and resulting 2.2 ng and 0.002% calculations are presented as the citing authors’ own, not as findings of Dal Monte et al. (Section passages have no page numbers in our copy.) (LLM, conf=0.82)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Premisecitation

    Four studies raised oxytocin concentrations above 20 pg/ml from basal levels below 5 pg/ml; Dal Monte et al. reported a rise to 80 pg/ml after nasal spray but no significant rise with a nebuliser, and Modi et al. reported a 100-fold plasma increase in macaques to more than 300 pg/ml and a rise to about 60 pg/ml after nebuliser application.

    “Of the above-mentioned studies, four (20,22,24,25) achieved oxytocin concentrations in excess of 20pg/ml from basal levels of <5pg/ml, while Dal Monte et al. reported a rise to 80pg/ml after nasal spray, but no significant rise with a nebulariser (23).Modi et al. reported a 100-fold increase in plasma in the macaque (to >300pg/ml), and a rise to ~60pg/ml (from 10pg/ml) after nebulariser”
    Quote in the paperSubstantial claim2 of 3 sources checked
    • cites [20] Striepens, 2013, Elevated cerebrospinal fluid and blood concentrations of oxytocin following its intranasal administration in humans, Sci Rep source

      Split into 2 atoms — 0 confirmed, 1 partially supported, 0 disputed, 0 misattributed, 1 unverifiable. Expand the claim to see per-atom verdicts.

      Experimental — accuracy not yet measured
    • cites [22] Neumann, 2013, Increased brain and plasma oxytocin after nasal and peripheral administration in rats and mice, Psychoneuroendocrinology source
    • cites [24] Chang, 2012, Inhaled oxytocin amplifies both vicarious reinforcement and self reinforcement in rhesus macaques (Macaca mulatta), Proc Natl Acad Sci U S A source

      Split into 2 atoms — 0 confirmed, 1 partially supported, 0 disputed, 0 misattributed, 1 unverifiable. Expand the claim to see per-atom verdicts.

      Experimental — accuracy not yet measured

  • May combine two claims.

    Premisecitation

    In 11 patients given 24 IU intranasal oxytocin, Striepens et al. observed no CSF increase at 45 or 60 minutes, although three patients sampled at 75 minutes had CSF oxytocin 64% above controls.

    “Striepens et al. (20) measured CSF oxytocin in 11 patients given 24IU oxytocin intranasally.Whereas Born et al. saw an increase after 10min (albeit with vasopressin, at a larger dose) (17), Striepens et al. saw no increase at 45 or 60min.However, three patients sampled at 75min had CSF levels 64% higher than controls (at ~30pg/ml).”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [20] Striepens, 2013, Elevated cerebrospinal fluid and blood concentrations of oxytocin following its intranasal administration in humans, Sci Rep source

  • May combine two claims.

    Premisecitation

    In macaques given 24 IU oxytocin, only aerosol produced a significant CSF increase (from about 20 to about 60 pg/ml); both spray and aerosol raised plasma oxytocin, and the same dose intravenously raised plasma to about 60,000 pg/ml without increasing CSF.

    “In a larger study, Modi et al. gave 24IU oxytocin (~5µg/kg body weight) to macaques by spray or aerosol; only the aerosol produced a significant increase in CSF (from ~20 to ~60pg/ml) (25).”
    • Also stated in: § Oxytocin penetration of the brain after intranasal administration · plain
      “Both spray and aerosol raised plasma oxytocin levels.Intravenous administration of the same dose raised plasma levels to ~60,000pg/ml with no increase in CSF.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [25] Modi, 2014, Aerosolized oxytocin increases cerebrospinal fluid oxytocin in rhesus macaques, Psychoneuroendocrinology source

      Split into 2 atoms — 0 confirmed, 2 partially supported, 0 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.

      Experimental — accuracy not yet measured

  • May combine two claims.

    Interpretationcitation

    Behavioral effects require higher oxytocin concentrations than peripheral effects, because oxytocin receptors desensitize and peripheral receptors are exposed to much lower oxytocin levels and are therefore more sensitive.

    “It is unsurprising that higher concentrations of oxytocin are needed for behavioral effects than for peripheral effects.As in most G protein-coupled receptors, agonist stimulation of oxytocin receptors leads to desensitization (27).Receptors at peripheral sites are exposed to much lower concentrations of oxytocin (1-10pg/ml), than receptors in the brain (1), so will be more sensitive to it.”
    Quote in the paperSubstantial claim1 of 2 sources checked
    • cites [27] Conti, 2009, Intracellular trafficking of the human oxytocin receptor: Evidence of receptor recycling via a Rab4/Rab5 “short cycle.”, Am J Physiol Endocrinol Metabol source
    • cites [1] Leng, 2008, Neurotransmitters and peptides: Whispered secrets and public announcements, J Physiol source

      The indexed copy (section labeled Abstract; page unavailable) estimates oxytocin at approximately 1000 pg/ml in extracellular fluid of the supraoptic nucleus, supporting the cited point that brain concentrations can be high. It does not establish the stated peripheral concentration, greater peripheral receptor sensitivity, or the comparison of doses needed for behavioral and peripheral effects. The citing sentence attributes receptor desensitization to a different reference, (27). (LLM, conf=0.86)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Premisecitation

    In rats, intranasal administration of 1 μg oxytocin did not activate the forebrain sites examined or the olfactory bulb.

    “By contrast, intranasal application of 1µg oxytocin in rats produced no activation at these or any other sites in the forebrain (28) -and no activation in the olfactory bulb, the postulated primary target of interneuronal transfer of oxytocin.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [28] Ludwig, 2013, Intranasal application of vasopressin fails to elicit changes in brain immediate early gene expression, neural activity and behavioural performance of rats, J Neuroendocrinol source

  • May combine two claims.

    Premisecitation

    Intravenous cholecystokinin releases oxytocin into the blood and hypothalamus, but other agents affect central and peripheral release differently; in dogs, opioids stimulate peripheral secretion while suppressing central secretion.

    “In response to i.v.cholecystokinin, oxytocin is released into the blood and in the hypothalamus (79), but several other agents affect release differentially: for instance, in dogs, opioids stimulate peripheral secretion but suppress central secretion (80).”
    Quote in the paperNot a substantial claim1 of 2 sources checked
    • cites [79] Neumann, 1994, Stimulation of oxytocin release within the supraoptic nucleus and into blood by CCK-8, Am J Physiol source
    • cites [80] Brown, 2001, Effect of centrally administered opioid receptor agonists on CSF and plasma oxytocin concentrations in dogs, Am J Vet Res source

  • May combine two claims.

    Premisecitation

    Wismer Fries et al. reported that urinary oxytocin and vasopressin in orphans were affected by early neglect, but their reported levels were nearly a million-fold too high for both peptides, using a method neither sensitive nor selective enough to measure either peptide in urine; the report drew criticism, and the authors later improved their methodology.

    “The discrepancy between measurements in unextracted and extracted plasma is two orders of magnitude, but when Wismer Fries et al. reported that urinary excretion of oxytocin and vasopressin in orphans was affected by early neglect, they reported levels that were, for both peptides, nearly a million fold too high, after applying a method that was neither sensitive enough or selective enough to”
    Quote in the paperSubstantial claim3 of 4 sources checked
    • cites [72] Wismer Fries, 2005, Early experience in humans is associated with changes in neuropeptides critical for regulating social behavior, Proc Natl Acad Sci U S A source

      Split into 2 atoms — 1 confirmed, 1 partially supported, 0 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.

      Experimental — accuracy not yet measured
    • cites [73] Anderson, 2006, Report of altered urinary oxytocin and AVP excretion in neglected orphans should be reconsidered, J Autism Dev Disord source
    • cites [74] Young, 2010, Bioanalytical inaccuracy: A threat to the integrity and efficiency of research, J Psychiatry Neurosci source

      Split into 2 atoms — 1 confirmed, 1 partially supported, 0 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.

      Experimental — accuracy not yet measured
    • cites [75] Seltzer, 2010, Social vocalizations can release oxytocin in humans, Proc Biol Sci source

      Split into 2 atoms — 0 confirmed, 0 partially supported, 0 disputed, 0 misattributed, 2 unverifiable. Expand the claim to see per-atom verdicts.

      Experimental — accuracy not yet measured

  • May combine two claims.

    Premisecitation

    Oxytocin receptors are present in the heart and linked to natriuretic hormone secretion; oxytocin has direct cardiac effects, and intranasal oxytocin in humans increases heart rate variability.

    “Oxytocin receptors are expressed in the heart, coupled to secretion of natriuretic hormone (48).Oxytocin has direct cardiac effects, and intranasal application in man increases heart rate variability (49).”
    Quote in the paperNot a substantial claim1 of 2 sources checked
    • cites [48] Gutkowska, 2012, Oxytocin revisited: Its role in cardiovascular regulation, J Neuroendocrinol source
    • cites [49] Kemp, 2012, Oxytocin increases heart rate variability in humans at rest: Implications for social approach-related motivation and capacity for social engagement, PloS One source

      The Heart Rate Variability results report increased HRV after intranasal oxytocin relative to placebo. The Introduction says oxytocin and its receptors are present in cardiac tissue, but only suggests that peripheral mechanisms may affect HRV; it does not establish a direct cardiac effect. The natriuretic-hormone statement carries a separate citation (48), so it is not assessed as a claim attributed to this paper. (LLM, conf=0.85)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Premisecitation

    This unreliability is attributed to publication bias, questionable statistical analysis, and methodological weaknesses.

    “attributed to a combination of publication bias, questionable statistical analysis and methodological weaknesses”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [98] Ioannidis, 2005, Why most published research findings are false, PLoS Med source

  • Probably not a substantial claim: may not pass S1 (asserted), S3 (load-bearing), S4 (based).

    Premisecitation

    Recent trials found no effect of intranasal oxytocin in MDMA users.

    “or in MDMA users (92)”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [92] Kuypers, 2014, No evidence that MDMA-induced enhancement of emotional empathy is related to peripheral oxytocin levels or 5-HT1a receptor activation, PloS One source

      The Abstract reports that intranasal oxytocin did not affect the study’s measures of empathy and social interaction in 20 MDMA users. But the Results (Empathy tests and questionnaires; page unavailable) report an effect on self-rated personal distress, so the unqualified claim of “no effect” is too broad. (LLM, conf=0.87)

      Experimental — accuracy not yet measured
    • Rests on an assumption: The recent trials cited as showing no effect had sufficient statistical power to detect effects of intranasal oxytocin.

  • May combine two claims.

    Premisecitation

    In rats, 1-2 ng of oxytocin given intracerebroventricularly facilitates suckling-induced bursting, while maternal behavior requires about 400 ng; partner preference in voles requires 10-100 ng/h, and maternal behavior in sheep requires 5 μg intracerebroventricularly.

    “In lactating rats, suckling evokes bursts of action potentials in oxytocin cells that result in pulsatile oxytocin secretion, and this bursting is facilitated by 1-2ng oxytocin i.c.v.(26).Effects on maternal behavior in the rat need much higher doses (~400ng) (4).Partner preference effects in voles require infusions of oxytocin at 10-100ng/h (5), and, to stimulate maternal behavior in sheep, it”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [26] Russell, 2003, The magnocellular oxytocin system, the fount of maternity: Adaptations in pregnancy, Front Neuroendocrinol source
    • cites [4] Pedersen, 1982, Oxytocin induces maternal behavior in virgin female rats, Science source
    • cites [5] Williams, 1994, Oxytocin administered centrally facilitates formation of a partner preference in female prairie voles (Microtus ochrogaster), J Neuroendocrinol source

  • May combine two claims.

    Premisecitation

    In dogs, intranasal oxytocin increases glucagon and insulin secretion, probably through peripheral actions, since intravenous oxytocin has similar effects in goats and dogs.

    “Intranasal application in dogs increases glucagon and insulin secretion (37), and this is probably mediated peripherally as intravenous oxytocin has a similar effect in goats (38) and dogs (39).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [37] Altszuler, 1981, Intranasal instillation of oxytocin increases insulin and glucagon secretion, Proc Soc Exp Med source
    • cites [38] Roh, 2014, Actions of intravenous injections of AVP and oxytocin on plasma ACTH, GH, insulin and glucagon concentrations in goats, Anim Sci J source
    • cites [39] Stock, 1985, Oxytocin infusions increase plasma levels of insulin and VIP but not of gastrin in conscious dogs, Acta Physiol Scand source

  • May combine two claims.

    Premisecitation

    Oxytocin regulates feeding and metabolism at several sites, and its receptors are present throughout the gastrointestinal tract and on gastric vagal nerve endings.

    “Oxytocin regulates feeding and metabolism at multiple sites (34,35).Its receptors are expressed throughout the gastrointestinal tract, and on gastric vagal nerve endings (36).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [34] Chaves, 2013, Role of oxytocin in energy metabolism, Peptides source
    • cites [35] Leng, 2008, Oxytocin and appetite, Prog Brain Res source
    • cites [36] Iwasaki, 2014, Peripheral oxytocin activates vagal afferent neurons to suppress feeding in normal and leptin-resistant mice: A route for ameliorating hyperphagia and obesity, Am J Physiol Regul Integr Comp Physiol source

  • May combine two claims.

    Interpretationreasoning

    Intranasal oxytocin causes only modest rises in CSF but large, prolonged increases in circulating oxytocin that greatly exceed physiological concentrations.

    “Although intranasal applications deliver only modest rises in CSF concentrations, they produce large and prolonged increases in circulating oxytocin, to levels far above those needed for physiological effects.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    Maejima et al. reported that 10 μg intranasal oxytocin activated Fos expression in the paraventricular nucleus, area postrema, and dorsal motor nucleus of the vagus; the area postrema lies outside the blood-brain barrier and should not be reachable from CSF, and the same areas were activated by systemic oxytocin.

    “Maejima et al. reported that intranasal administration of a higher dose of oxytocin (10µg) activated Fos expression at the paraventricular nucleus, the area postrema and the dorsal motor nucleus of the vagus (29).The area postrema is outside the blood-brain barrier, and should not be accessible to oxytocin from the CSF.These same areas were also activated by oxytocin given systemically.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [29] Maejima, 2015, Nasal oxytocin administration reduces food intake without affecting locomotor activity and glycemia with c-Fos induction in limited brain areas, Neuroendocrinology source

  • Probably not a substantial claim: may not pass S4 (based).

    Interpretationnone given

    A 24 IU intravenous bolus of oxytocin would produce a peak plasma concentration above 1,400 pg/ml, about three orders of magnitude higher than physiological levels.

    “If 24IU oxytocin were delivered as a bolus intravenously, the peak plasma concentration would exceed 1,400pg/ml, three orders of magnitude higher than physiological concentrations.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    In Hoover's study of 1,806 women, intranasal oxytocin augmented labor at 1-4 doses of 0.4-0.8 IU every 20 minutes (maximum 3.2 IU); equivalent effects from intravenous infusion of 1-2 mU/min led to an estimate that about 1% of intranasally applied oxytocin enters the circulation.

    “Hoover studied 1,806 women who had been given intranasal oxytocin during childbirth (31).Labor was stimulated by 1-4 doses of 0.4-0.8IUgiven at 20-min intervals -a total of, at most, 3.2IU.Equivalent effects were achieved by intravenous infusion of 1-2mU/min, giving rise to the estimate that ~1% of intranasally-applied oxytocin enters the circulation (32).”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [31] Hoover, 1971, Intranasal oxytocin in eighteen hundred patients. A study on its safety as used in a community hospital, Am J Obstet Gynecol source
    • cites [32] Hendricks, 1960, Use of intranasal oxytocin in obstetrics. 1. A laboratory evaluation, Am J Obstet Gynecol source

  • Probably not a substantial claim: may not pass S4 (based).

    Premisenone given

    Many published oxytocin measurements were obtained with methods that have been discredited.

    “Reports in the literature of oxytocin measurements include many that have been made with discredited methodology.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationcitation

    In seven studies, very large intranasal doses of oxytocin produced only modest increases in CSF, and two found no increase; at most 0.005% of the intranasal dose reaches CSF within an hour.

    “All seven studies administered enormous amounts of peptide intranasally -in every case more than the pituitary content as a bolus -yet found only modest rises in CSF: two found no rise.At most, 0.005% of intranasally injected oxytocin reaches the CSF within an hour.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    In rats given subcutaneous oxytocin, plasma levels rose about 500-fold while CSF levels rose only modestly, and only 0.002% of the dose reached the central nervous system by 10 minutes.

    “The effectiveness of the blood-brain barrier for oxytocin was measured by Mens et al., who injected 5µg subcutaneously in rats, increasing plasma concentrations 500-fold to ~38,600pg/ml (10).Increases in CSF were modest; concentrations increased from ~40pg/ml to ~150pg/ml.The authors calculated that just 0.002% of the injected oxytocin had reached the CNS after 10min, when CSF concentrations were”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [10] Mens, 1983, Penetration of neurohypophyseal hormones from plasma into cerebrospinal fluid (CSF): Half-times of disappearance of these neuropeptides from CSF, Brain Res source

  • May combine two claims.

    Premisereasoning

    In Born et al.'s study, approximately 4.5 ng of vasopressin reached the CSF, representing 0.005% of the administered dose, if the rise came from the administered peptide rather than indirect endogenous release.

    “Estimating the CSF volume as 300ml, it seems that ~4.5ng of vasopressin reached the CSF: 0.005% of the given dose -assuming that the rise was due to administered peptide and not endogenous release triggered indirectly.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [17] Born, 2002, Sniffing neuropeptides: A transnasal approach to the human brain, Nat Neurosci source

  • Probably not a substantial claim: may not pass S4 (based).

    Interpretationreasoning

    Because intracranial microdialysis inevitably damages blood vessels around the probe, the measured oxytocin may come from local leakage from injured vessels.

    “Intracranial microdialysis inevitably ruptures blood vessels around the probe, so these measurements might reflect local passage into the brain from damaged vessels.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Born et al. achieved plasma vasopressin of 20 pg/ml after 40 IU intranasal, higher than Robertson et al. reported for any patient, including those with pathologically elevated vasopressin; maximal urine concentrating ability in humans occurs at about 5 pg/ml.

    “Born et al. achieved plasma concentrations of 20pg/ml after giving 40IU vasopressin (17).These are higher than Robertson et al. reported for any patient, including those with pathologically elevated vasopressin secretion; in man, maximal urine concentrating ability is achieved at a vasopressin concentration of ~5pg/ml (33).”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [17] Born, 2002, Sniffing neuropeptides: A transnasal approach to the human brain, Nat Neurosci source
    • cites [33] Robertson, 1970, Immunoassay of plasma vasopressin in man, Proc Natl Acad Sci U S A source

  • May combine two claims.

    Premisecitation

    In rats, 20 μg intranasal oxytocin produced no change in CSF oxytocin at 45 minutes, but microdialysate oxytocin doubled at 30-60 minutes and correlated with a four-fold rise in plasma.

    “Neumann et al. gave 20μg of oxytocin intranasally to rats (20 times the pituitary content) and found no change in CSF oxytocin after 45min (22).However, they found a doubling of oxytocin levels in microdialysates of brain regions collected at 30-60min, correlated with a four-fold rise in plasma.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [22] Neumann, 2013, Increased brain and plasma oxytocin after nasal and peripheral administration in rats and mice, Psychoneuroendocrinology source

  • May combine two claims.

    Premisenone given

    In animal studies, 1 ng intracerebroventricularly is the lowest oxytocin dose shown to produce a behavioral effect, and 2 ng induces c-fos expression in rat brain regions that express oxytocin receptors, including the amygdala and hypothalamus.

    “Thus 1ng oxytocin is the lowest i.c.v.dose shown to elicit a behavioural effect in animal studies, and 2ng induces expression of the immediate-early gene c-fos in rat brain regions where oxytocin receptors are expressed, including in the amygdala and hypothalamus.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    Intranasal oxytocin achieves higher concentrations in blood than in CSF, and because baseline plasma levels are lower than CSF levels, the relative increase in blood is much larger.

    “Intranasal application achieves higher concentrations of peptide in blood than in CSF, and, as basal concentrations in plasma are lower than in CSF, the proportional change in blood is much greater.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Oxytocin is released into the brain in large amounts from the soma and dendrites of neurons that project to the pituitary; this release is semi-independent of axonal release and is partly controlled by mobilization of intracellular calcium.

    “Oxytocin is released into the brain in large amounts from the soma and dendrites of neurons that project to the pituitary-but this is semi-independent of axonal release, being governed in part by mobilisation of intracellular calcium, a mechanism not present at the terminals (2).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [2] Ludwig, 2006, Dendritic peptide release and peptide-dependent behaviours, Nat Rev Neurosci source

  • May combine two claims.

    Premisecitation

    Most central oxytocin innervation probably comes from non-neuroendocrine paraventricular nucleus neurons that do not project to the pituitary, although some magnocellular neurons project sparsely to areas such as the amygdala and septum.

    “Some magnocellular neurons project sparsely to some other brain areas, including the amygdala and septum, but it seems likely that most of the central innervations derives from non-neuroendocrine neurons of the paraventricular nucleus (76) that do not project to the pituitary.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [76] Knobloch, 2012, Evoked axonal oxytocin release in the central amygdala attenuates fear response, Neuron source

  • May combine two claims.

    Premisecitation

    At moderately high concentrations, oxytocin activates V1 vasopressin receptors, which are present at many peripheral sites including the olfactory epithelium; the consequences of this activation are unknown.

    “Finally, oxytocin at moderately high concentrations is an agonist at V1 vasopressin receptors, and these are expressed at many peripheral sites (including the olfactory epithelium (56); the consequences of activating these is not known).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [56] Levasseur, 2004, Anatomical and functional evidence for a role of arginine-vasopressin (AVP) in rat olfactory epithelium cells, Eur J Neurosci source

  • May combine two claims.

    Premisecitation

    Oxytocin is released into blood and brain during parturition, but in sheep plasma levels were elevated for only 15 minutes postpartum while CSF levels remained increased for more than 120 minutes.

    “Oxytocin is released into blood and brain during parturition, but in sheep (81), plasma concentrations were only elevated for 15min postpartum whereas those in CSF were increased for >120min.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [81] Kendrick, 1991, Cerebrospinal fluid and plasma concentrations of oxytocin and vasopressin during parturition and vaginocervical stimulation in the sheep, Brain Res Bull source

  • May combine two claims.

    Premisecitation

    One paper concluded that adolescent oxytocin exposure increases plasma oxytocin in adulthood, but its extracted samples showed no group differences; the authors built their interpretation on unextracted plasma measurements.

    “One of those papers concludes that adolescent exposure to oxytocin increases plasma oxytocin in adulthood, and it might be expected that this conclusion was drawn from data on extracted plasma (70).Not so: the data from extracted samples showed no differences between groups: instead, the authors built their interpretation on the measurements of unextracted plasma.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [70] Suraev, 2014, Adolescent exposure to oxytocin, but not the selective oxytocin receptor agonist TGOT, increases social behavior and plasma oxytocin in adulthood, Horm Behav source

  • May combine two claims.

    Premisecitation

    In rhesus monkeys, CSF oxytocin was associated with social behaviour, whereas plasma oxytocin was not, and plasma oxytocin did not track same-session CSF oxytocin.

    “while CSF oxytocin correlated with social behaviour, plasma levels did not, nor did they correlate with CSF levels collected in the same session (88).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [88] Winslow, 2003, Rearing effects on cerebrospinal fluid oxytocin concentration and social buffering in rhesus monkeys, Neuropsychopharmacology source

  • May combine two claims.

    Premisereasoning

    Appetite-related and some reproductive stimuli activate both central and peripheral oxytocin release, but the timing and magnitude differ, and these differences are amplified by the distinct pharmacokinetics of the two compartments.

    “Appetite-related stimuli and some reproductive stimuli activate both central and peripheral oxytocin release, but the timings and extent of these actions differ, and differences are exaggerated by the different pharmacokinetics in the two compartments.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    Stress affects both central and peripheral oxytocin secretion, but in rats swim stress increases hypothalamic and plasma oxytocin, whereas novelty stress increases CSF but not plasma oxytocin.

    “Stress affects both central and peripheral secretion of oxytocin-but while swim stress in rats increases oxytocin release in the hypothalamus and into plasma (82), novelty stress increases CSF but not plasma concentrations (83).”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [82] Wotjak, 1998, Dissociated central and peripheral release of vasopressin, but not oxytocin, in response to repeated swim stress: New insights into the secretory capacities of peptidergic neurons, Neuroscience source
    • cites [83] Ivanyi, 1991, Differential effects of emotional and physical stress on the central and peripheral secretion of neurohypophysial hormones in male rats, Life Sci source

  • May combine two claims.

    Premisereasoning

    Many studies have based conclusions on questionable plasma oxytocin measurements, and some incorrectly claim that plasma measurements reliably reflect oxytocin release in the brain.

    “Many studies have drawn conclusions from highly questionable measurements of plasma oxytocin, and others mistakenly claim that plasma measurements reliably reflect oxytocin release in the brain.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    In rats, hyperosmotic stimuli increase oxytocin release from both dendrites and nerve terminals, but on different time scales; dendritic release rises as plasma concentrations fall.

    “Hyperosmotic stimuli increase oxytocin release from both dendrites and nerve terminals in rats, but on different time scales; dendritic release is increased as plasma concentrations fall (2).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [2] Ludwig, 2006, Dendritic peptide release and peptide-dependent behaviours, Nat Rev Neurosci source

  • May combine two claims.

    Premisecitation

    When α-melanocyte stimulating hormone acts at MC4 receptors, oxytocin is released from magnocellular neuron dendrites while the neurons' electrical activity and peripheral oxytocin secretion are inhibited.

    “In response to α-melanocyte stimulating hormone (acting at MC4 receptors), oxytocin is released from dendrites of magnocellular neurons, but their electrical activity and peripheral oxytocin secretion is inhibited (78).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [78] Sabatier, 2003, Alpha-melanocyte-stimulating hormone stimulates oxytocin release from the dendrites of hypothalamic neurons while inhibiting oxytocin release from their terminals in the neurohypophysis, J Neurosci source

  • May combine two claims.

    Premisecitation

    In lactating rhesus monkeys, Amico et al. found that CSF oxytocin variations were independent of the suckling stimulus and plasma oxytocin concentrations, and noted that CSF but not plasma levels show a circadian variation; they concluded that oxytocin release into CSF is disassociated from release into the peripheral circulation.

    “In lactating rhesus monkeys, Amico et al. (86) found that”
    • Also stated in: § Central and peripheral release of oxytocin · plain
      “variations in the concentrations of oxytocin in CSF were independent of the suckling stimulus and plasma oxytocin concentrations”
    • Also stated in: § Central and peripheral release of oxytocin · plain
      “release of oxytocin into the CSF of lactating monkeys is disassociated from release into the peripheral circulation”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [86] Amico, 1990, Pattern of oxytocin concentrations in the plasma and cerebrospinal fluid of lactating rhesus monkeys (Macaca mulatta): evidence for functionally independent oxytocinergic pathways in primates, J Clin Endocrinol Metabol source
    • cites [87] Perlow, 1982, Oxytocin, vasopressin, and estrogen-stimulated neurophysin: Daily patterns of concentration in cerebrospinal fluid, Science source

  • May combine two claims.

    Premisecitation

    In lactating rats, hypothalamic oxytocin release in response to suckling precedes peripheral secretion, but in guinea pigs simultaneous measurements showed a large plasma increase during suckling with no change in CSF, leading the authors to conclude that CSF oxytocin reflects secretion from centrally projecting neurons that are functionally independent of magnocellular neurosecretory neurons.

    “In lactating rats, oxytocin is released in the hypothalamus in response to suckling before any peripheral secretion (84), but in guinea pigs, simultaneous measurements revealed a large increase in plasma during suckling but no change in CSF (85), leading the authors to conclude that CSF levels reflect secretion from centrally projecting neurons that are functionally independent of the magno”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [84] Moos, 1989, Release of oxytocin within the supraoptic nucleus during the milk ejection reflex in rats, Exp Brain Res source
    • cites [85] Robinson, 1982, Oxytocin and neurophysin in plasma and CSF during suckling in the guinea-pig, Neuroendocrinology source

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    In psychological research, arguments are often made to block publication and interpretation of null results, and questionable practices may extinguish null results.

    “the field often constructs arguments to block the publication and interpretation of null results and that null results may be extinguished through questionable researcher practices”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [99] Ferguson, 2012, A vast graveyard of undead theories: Publication bias and psychological science’s aversion to the null, Perspect Psychol Sci source
43 of 43

  • The paper relies on this without support.

    CSF oxytocin concentration is a valid proxy for behaviorally relevant oxytocin penetration into the brain.

    “At most, 0.005% of intranasally injected oxytocin reaches the CSF within an hour.”

  • The paper relies on this without support.

    Doses of oxytocin required to produce behavioral effects in animals indicate the brain concentrations needed for behavioral effects in humans.

    “Are these enormous intranasal doses enough to deliver effective concentrations of oxytocin into the brain?”

  • The paper relies on this without support.

    The recent trials cited as showing no effect had sufficient statistical power to detect effects of intranasal oxytocin.

    “Several recent trials conform to some of these conditions, particularly in reporting clear primary outcomes.”
3 of 3

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • It is uncertain whether standard intranasal oxytocin doses of 24 to 40 IU can deliver sufficient oxytocin to the brain to produce significant changes in individuals.

    “it is uncertain whether the standard doses used in OT research (between 24 and 40 IU) can deliver sufficient quantities of OT to the brain in order to produce significant changes in individuals”

    From Is there a Publication Bias in Behavioural Intranasal Oxytocin Research on Humans? Opening the File Drawer of One Laboratory (2016) · cites this paper as [24]

    In “How much oxytocin must enter the brain for a behavioral effect?” (page not available), the paper explicitly questions whether conventional intranasal doses deliver effective brain concentrations. The brain-penetration section reports only modest CSF increases, including after 24 IU of oxytocin. Our copy does not establish 24–40 IU as the standard oxytocin-dose range; its mention of 40 IU concerns vasopressin. (LLM, conf=0.84)

    Experimental — accuracy not yet measured

  • The dosage and timing of intranasal oxytocin tasks are based on three assumptions that have not been directly or reliably tested: that intranasal oxytocin crosses the blood-brain barrier, that 24-40 IU is sufficient for behavioral changes, and that intranasal oxytocin pharmacokinetics mimics vasopressin.

    “The dosage of IN-OT and typical timing of tasks following IN-OT administration is based on three assumptions that to our knowledge have not been directly or reliably (i.e. through several replications) tested: that IN-OT crosses the brain-blood barrier following administration, that 24-40 IU is a sufficient dose to produce behavioral changes, and that IN-OT pharmacokinetics mimics that of vasopres”

    From Is there a Publication Bias in Behavioural Intranasal Oxytocin Research on Humans? Opening the File Drawer of One Laboratory (2016) · cites this paper as [24]

    In “Oxytocin penetration of the brain after intranasal administration” (page unavailable), the paper questions whether CSF measurements establish substantial brain penetration and contrasts the timing of oxytocin findings with a vasopressin study. “Peripheral targets for oxytocin” (page unavailable) calls for proper dose-response studies, supporting doubt about an established effective dose. The paper does not state that task timing rests on an untested assumption that intranasal oxytocin’s pharmacokinetics mimic vasopressin’s, or establish the claimed three-assumption account as a whole. (LLM, conf=0.84)

    Experimental — accuracy not yet measured

  • The pre-study odds of studies investigating the effect of intranasal oxytocin are low, primarily due to limitations in deep brain penetration of oxytocin when administered intranasally.

    “Although the idea that manipulating OT in humans could influence social behavior is supported by rigorous animal research, we argue that the pre-study odds of studies investigating the effect of IN-OT still would be low, primarily due to limitations in deep brain penetration of OT when administered intranasally (2, 19).”

    From Statistical and Methodological Considerations for the Interpretation of Intranasal Oxytocin Studies (2016) · cites this paper as [19]

  • In rats, low doses of oxytocin decreased locomotor activity and higher doses caused sedation.

    “They showed that low doses of OT led to a decrease of locomotor activity and that higher doses led to clear signs of sedation.”

    From Is there a Publication Bias in Behavioural Intranasal Oxytocin Research on Humans? Opening the File Drawer of One Laboratory (2016) · cites this paper as [24]

    The section “How much oxytocin must enter the brain for a behavioral effect?” discusses dose-dependent effects in rats, but not decreased locomotor activity or sedation. A cited study’s title in the References says nasal oxytocin reduced food intake without affecting locomotor activity; it does not establish what happened at the low and high doses in the claim. Searches for locomotor activity and sedation found no passage reporting those effects. (LLM, conf=0.72)

    Experimental — accuracy not yet measured

  • It is unclear whether peripheral measures of OXT are accurate approximations for levels of OXT in the central nervous system.

    “it is unclear whether these peripheral measures of OXT are accurate approximations for levels of OXT in the central nervous system24.”

    From Effect of age and autism spectrum disorder on oxytocin receptor density in the human basal forebrain and midbrain (2018) · cites this paper as [24]

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Related

Authors
Leng, G., & Ludwig, M.
Affiliations
University of Edinburgh (GB)
Corresponding author
Leng, Gareth
ORCID
Venue
Biological Psychiatry
Publisher
Elsevier BV
Published
2016-02
Volume
79
Issue
3
Pages
243-250
ISSN
0006-3223 (ISSN-L)
DOI
10.1016/j.biopsych.2015.05.003
OpenAlex
W1750764127
Cited by
615
References
113
Citations by year
2026: 23 · 2025: 25 · 2024: 27 · 2023: 29 · 2022: 35 · 2021: 73 · 2020: 76 · 2019: 59 · 2018: 64 · 2017: 75 · 2016: 77 · 2015: 29
FWCI
129.92
Type
journal article
Language
en
Open access
Licence
Locations
  • Biological Psychiatry (publishedVersion)
  • PubMed (publishedVersion)
  • Edinburgh Research Explorer (University of Edinburgh) (submittedVersion, other-oa)
Funders
  • Biotechnology and Biological Sciences Research Council (BB/J004723)
  • Edinburgh Patrick Wild Centre, and the European Union’s Seventh Framework Programme for research, technological development and demonstration (245009, 607310)
Topics
  • Social Sciences › Psychology › Social Psychology › Neuroendocrine regulation and behavior
  • Life Sciences › Neuroscience › Sensory Systems › Olfactory and Sensory Function Studies
  • Life Sciences › Neuroscience › Behavioral Neuroscience › Stress Responses and Cortisol
Keywords
intranasal oxytocin, cerebrospinal fluid, dose-response relationship, publication bias, questionable research practices, oxytocin antagonist
MeSH terms
Administration, Intranasal, Brain, Dose-Response Relationship, Drug, Humans, Oxytocin, Social Behavior

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Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-08.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-08.

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