Romantic love has an adaptive function in human evolution. It increases reproductive success in sexual relations between men and women through the hormone of love. The evolution of animal and human bonding results in the evolution of love hormones.

When men and women are in passionate love, many psychophysiological and neuropsychological processes occur in their brains and bodies. They affect how their minds and behaviors function. In recent decades, researchers have revealed the important role that hormones plays in passionate love. They conducted studies on neuroimaging, biochemistry, and hormones (Hatfield & Rapson, 2009; Gangestad & Grebe, 2017; Sorokowski et al., 2019).

Hormones Play a Role in Romantic Love

These changes are especially pronounced when they are falling in love. Being close to a beloved partner elicits strong romantic feelings and produces corresponding hormonal changes. The hormones cortisol, testosterone, oxytocin, prolactin, and estradiol engage in emotional and behavioral reactions associated with love feelings.

For example, men and women who are in romantic love have higher cortisol. The excited state of passionate arousal they experience when they fall in love causes the increased cortisol level. Other hormonal changes also facilitate pair bonding and commitment.

Some discoveries about the effects of various hormones on romantic love are consistent and well-known. Other findings are sometimes contradictory and need further research. A recent study indicated one more hormonal secret of love that is worthy of our attention (Sorokowski et al., 2019).

Does Love Increase a Woman’s Fertility?

Researchers from the University of Wrocław, Poland, conducted the study to show that love produces adaptive hormonal changes in the female body. These changes increase a woman’s fertility when she is in love (Sorokowski et al., 2019).

In their study, researchers measured the levels of several hormones in women in the early follicular phase of the menstrual cycle. They compared the blood serum levels of estradiol, cortisol, free testosterone, prolactin, luteinizing hormone, and follicle-stimulating hormone of those women who were at the beginning of passionate romantic relationships with those who were not in love.

Hormones of Love Involved in Experience of Emotion

Researchers reported that women in love have higher levels of gonadotropins and lower free testosterone levels compared to those who are not in love. At the same time, women in love have the same levels of cortisol, prolactin, and estradiol. Researchers also revealed that the estradiol-to-testosterone ratio is higher in women in love in comparison with women who are not in love. Researchers suggest possible explanations for these results based on their associations with other confounding factors they identified in their study. They admit that some of the results aren’t completely convincing and that more research needs to be done.

Here Is One More Hormone of Love

Nevertheless, this study seems about to crack one more hormonal secret of romantic love. It turned out that the experience of falling in love plays an adaptive function. It increases the likelihood that the romantic couple will conceive offspring in their sexual relations. This discovery explains why men and women across the world tend to experience not only sexual attraction but also love. Heterosexual love is an important adaptive psychological mechanism that increases women’s physiological ability to conceive a child.