Copyright ©The Author(s) 2018. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Obstet Gynecol. Oct 22, 2018; 7(2): 17-23
Published online Oct 22, 2018. doi: 10.5317/wjog.v7.i2.17
Endorphins, oxytocin, sexuality and romantic relationships: An understudied area
Marjan Khajehei, Elmira Behroozpour
Marjan Khajehei, Department of Women’s and Newborn Health, Westmead Hospital, Westmead 2145, Australia
Marjan Khajehei, School of Women’s and Children’s Health, University of New South Wales, Sydney 2000, Australia
Marjan Khajehei, Westmead Medical School, University of Sydney, Sydney, Australia 2000
Elmira Behroozpour, Department of Microbiology, Azad University of Saveh, Saveh 367546, Iran
Author contributions: Khajehei M and Behroozpor E contributed to literature search, summarising the findings, preparing the manuscript draft and approving the final draft.
Conflict-of-interest statement: The authors declare no conflict of interest.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Marjan Khajehei, BSc, MSc, PhD, Department of Women’s and Newborn Health, Westmead Hospital, Westmead, Room 3046, Westmead 2145, Australia. marjan.khajehei@health.nsw.gov.au
Telephone: +61-2-88903706 Fax: +61-2-98458664
Received: June 22, 2018
Peer-review started: June 22, 2018
First decision: September 3, 2018
Revised: September 10, 2018
Accepted: October 12, 2018
Article in press: October 12, 2018
Published online: October 22, 2018

Endorphins are the body’s natural opioids that are created and released by the central nervous system, hypothalamus and pituitary gland. Endorphins have a reputation for pain reduction, enhancing excitement or satisfaction, boosting confidence, enabling control of emotions and generating feelings of euphoria, and are involved in the natural reward cycle. There is also evidence in the literature suggesting the role of endorphins in sexuality (including sexual function and sexual behaviours), as they may regulate the release of sex hormones, prolactin and growth hormone, which are involved in sexual function and love. Endogenous oxytocin is another intrinsic hormone whose role in inducing labour contractions, the delivery of the baby and stimulating lactation has been well studied. However, the potential impact of endorphins and oxytocin on sexuality and romantic relationships is not well understood. This article reviews the research on endorphins and endogenous oxytocin and how they relate to human sexuality and romantic relationships. Some animal studies report the effect of endorphin and oxytocin on sex hormones and mating behaviours, but these findings have not been supported by research into human behaviour, indicating many gaps in knowledge relating to the association between these hormones and human sexuality.

Keywords: Romantic relationship, Sexual behaviour, Sexual function, Endorphins, Oxytocin, Sexuality

Core tip: Less is known about the association between endogenous opioids and sexual function and behaviors in humans. There are mixed reports regarding the impact of oxytocin on sexuality and romantic relationships. The importance of physiological changes during sexual activity and how they can affect human relationships and the gaps in the literature highlight the need for high-quality research to extend our understanding of the hormonal physiology of sexual function and the role of endorphins and oxytocin in human sexuality.