Sex-Related Differences in Plasma Oxytocin Levels in Humans

Donatella Marazziti1, *, Stefano Baroni1, Federico Mucci1, Armando Piccinni1, Ilenia Moroni1, Gino Giannaccini2, Claudia Carmassi1, Enrico Massimetti3, Liliana Dell’Osso1
1 Dipartimento di Medicina Clinica e Sperimentale, Section of Psychiatry, University of Pisa, Pisa, Italy
2 Dipartimento di Farmacia, University of Pisa, Pisa, Italy
3 ASST, Bergamo Ovest, SSD Servizio Psichiatrico diagnosi e cura, Treviglio, Italy

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© 2019 Marazziti et al.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: ( This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to this author at the Dr. Donatella Marazziti, Dipartimento di Medicina Clinica e Sperimentale, Section of Psichiatry, University of Pisa, Via Roma, 67, 56100 Pisa, Italy; Tel: +39 050 2219768;Fax: +39 050 2219787; E-mail:



Increasing evidence supports a key role of Oxytocin (OT) as a modulator of social relationships in mammals.


The aim of the present study was to investigate possible sex-related differences in plasma OT levels in human beings.


Forty-five healthy men and 45 women (mean age: 34.9 ± 6.2 years), were included in the study. Plasma preparation, peptide extraction and OT radioimmunoassay were carried out according to standardized methods.


The results showed that OT plasma levels (pg ̸ ml, mean ± SD) were significantly higher in women than in men (4.53 ± 1.18 vs 1.53 ± 1.19, p ˂ 0.001).


The present finding demonstrates sex-related differences in plasma OT levels in humans. It is tempting to hypothesize that such differences might be related to behaviours, attitudes, as well as susceptibility to stress response, resilience and social emotions specific of women and men.

Keywords: Dymorphic changes, Humans, Oxytocin, Plasma levels, Social emotions, AVP receptors.