Oxytocin is released at orgasm and is associated with both sexual pleasure and the formation of emotional bonds. (Wikipedia）
A key hormone released during sex is oxytocin, also known as the ‘cuddle hormone’. … It’s also the key to bonding, as it increases levels of empathy. Women produce more of this hormone, although it’s not clear why, and this means they are more likely to let their guard down and fall in love with a man after sex. However, the problem is that the body can’t distinguish whether the person we’re with is a casual fling or marriage material — oxytocin is released either way. (Sex: Why it makes women fall in love – but just makes men want MORE! By ANNA HODGEKISS UPDATED: 22:02 GMT, 29 August 2011 Mail Online)
- Researchers in one 2012 study found that couples in the first stages of romantic attachment had significantly higher levels of oxytocin than their unattached counterparts.
- One 2013 review summarized all of oxytocin’s possible relationship-enhancing effects.
（Why Is Oxytocin Known as the ‘Love Hormone’? And 11 Other FAQs healthline.com)
- 6 Effects of the “Love Hormone” Oxytocin (Makati Medical Center)
(The New York Times Jan 22, 1991)
- Social effects of oxytocin in humans: context and person matter. Trends in Cognitive Sciences, July 2011, Vol. 15, No. 7
- The orgasmic history of oxytocin: Love, lust, and labor. Indian J Endocrinol Metab. 2011 Sep; 15(Suppl3): S156–S161. doi: 10.4103/2230-8210.84851. PMC3183515
- Gender differences in sexual motivation. Janice Hiller Published Online: 27 Jul 2005;The Journal of Men’s Health and Gender VOL. 2, NO. 3 (Full tesxt at Research Gate)
The impact of sexual activity on endogenous OXT release is informed by numerous studies showing increased OXT plasma concentrations after orgasm in humans (67–70) [but see also (71)].
67. Ogawa S, Kudo S, Kitsunai Y, Fukuchi S (1980): Increase in oxytocin secretion at ejaculation in male. Clin Endocrinol (Oxf) 13:95–97.
68. Carmichael MS, Warburton VL, Dixen J, Davidson JM (1994): Relationships among cardiovascular, muscular, and oxytocin responses during human sexual activity. Arch Sex Behav 23:59–79.
69. Murphy MR, Checkley SA, Seckl JR, Lightman SL (1990): Naloxone inhibits oxytocin release at orgasm in man. J Clin Endocrinol Metab 71:1056–1058.
70. Blaicher W, Gruber D, Bieglmayer C, Blaicher AM, Knogler W, Huber JC (1999): The role of oxytocin in relation to female sexual arousal. Gynecol Obstet Invest 47:125–126.
71. Kruger TH, Schiffer B, Eikermann M, Haake P, Gizewski E, Schedlowski M (2006): Serial neurochemical measurement of cerebrospinal fluid during the human sexual response cycle. Eur J Neurosci 24:3445–3452.