Men aspire to maintain their testosterone levels at an all-time high to deliver an optimal performance in their sexual relationships in between the sheets. Not only is testosterone associated with sexual activity, the male hormone is also linked to manliness and strength. However, despite its benefits, too much of it may be bad for long-term relationships. According to a recent study published in the journal Hormones and Behavior, men and women in satisfying and committed relationships are typically found to have lower testosterone levels.

"These findings suggest that once people are in a relationship, lower levels of testosterone may be beneficial — or may reflect better ongoing relationship dynamics," said Robin Edelstein, lead author of the study and University of Michigan associate professor of psychology, in the news release. Generally, higher testosterone is thought to be associated with attracting sexual partners, but not compatible with some kinds of long-term relationships. Although the association between high T levels in men and relationship dissatisfaction, Edelstein and her colleagues reveal that less is known about the potential dyadic associations between testosterone and relationship quality in couples.

The team of researchers at the University of Michigan sought to assess relationship satisfaction, commitment, and investment in heterosexual couples to determine the impact of an individual’s own and his/her partner’s testosterone levels. Thirty-nine couples — 78 men and women — part of a larger study of neuroendocrine responses to intimacy — were recruited for the study. Women’s age ranged from 18 to 32, while men’s age ranged from 18 to 31. Some of these couples were in relationships from two months to seven years, while three couples were married or engaged, and two couples were parents.

To assess participants’ relationship quality, the researchers used three subscales from the widely used Investment Model Scale. The subscales included items such as "My relationship is close to ideal" for satisfaction, "I want our relationship to last forever" for commitment, and "I have invested a great deal into our relationship that I would lose if the relationship were to end" for investment, according to Medical Xpress. To measure testosterone levels, participants rinsed their mouths with water, and then the researchers used polypropylene tubes to collect 5 milliliters of salvia. The samples were frozen in the laboratory until further processing in the University of Michigan Core Assay Facility.

The findings revealed men and women who reported higher relationship satisfaction and commitment had lower levels of testosterone than those who reported lower satisfaction and commitment. This concluded that the quality of a person’s relationship was associated with his/her and his/her partner’s testosterone levels. The couples were more satisfied and committed when they or their partner had low testosterone levels, the researchers reported. They believe the study warrants further investigation on whether their findings can apply to more established relationships and among older individuals.

In a similar 2003 study, also published in the journal Hormones and Behavior, the researchers found men in committed, romantic relationships had 21 percent lower testosterone levels than men not involved in such relationships. The testosterone levels of married men and unmarried men who were involved in committed, romantic relationships did not differ. This finding highlights that male pair bonding status is a more significant predictor of testosterone levels than marital status.

While high testosterone levels are associated with sexuality, manliness, and strength, lower testosterone levels can lead to more satisfaction and commitment in relationships. This perhaps can lead to a more established relationship between testosterone levels and relationship quality. According to MedlinePlus, normal testosterone levels for men and women are 300 to 1,000 nanograms per deciliter (ng/dL) and 15 to 70 ng/dL, respectively.

Sources:

Chopik WJ, Edelstein RS, Goldey KL, van Anders SM, Wardecker BM. Dyadic associations between testosterone and relationship quality in couples. Hormones and Behavior. 2014.

Burnham TC, Chapman JF, Ellison PT, Gray PB, Lipson SF, McIntyre MH. Men in committed, romantic relationships have lower testosterone. Hormones and Behavior. 2003.