Lower testosterone levels may lead men to have less sex with fewer partners, but a new study suggests low levels in both men and women may also increase relationship quality overall.
Lower testosterone levels may lead men to have less sex with fewer partners, but a new study suggests they may also increase relationship quality overall.
Researchers from the University of Michigan recruited 39 heterosexual couples, asked how their relationships were going, and correlated their answers with testosterone levels in their saliva.
The results, which were published in the journal Hormones and Behavior, showed that satisfaction and commitment, for both men and women, were negatively associated with their own testosterone levels.
Men even experienced less satisfaction with and felt less commitment to women who had higher testosterone levels.
“The assumption is generally that high testosterone is good for sexual relationships,” said Robin Edelstein, PhD, the study’s lead author, in a news release that accompanied publication of the study results.
“These findings suggest that once people are in a relationship, lower levels of testosterone may be beneficial—or may reflect better ongoing relationship dynamics.”
Participant age ranged from 18 to 32, while relationship duration ranged from two months to seven years. Only three couples were either married or engaged and just two had children.
To evaluate the relationships for satisfaction, commitment and investment, researchers used three sets of statements from the Investment Model Scale.
Those statements ranged from “My relationship is close to ideal” and “Our relationship makes me very happy” to “I want our relationship to last forever” and “My partner and I share many memories.”
Participants quantified their agreement with each statement on a scale that ranged from 1 (do not agree at all) to 9 (agree completely).
To measure testosterone levels, the researchers asked participants to rinse their mouths and spit 5 ml of saliva into sterilized tubes, which were then frozen until they were tested with a commercially available kit.
Subsequent analysis of both the men and women showed a significant negative correlation between a person’s own testosterone levels and his or her levels of satisfaction, commitment and investment.
The case was not so clear when it came to partner testosterone levels.
For men, there was a significant negative relationship between partner testosterone and both satisfaction with and commitment to relationships.
For women, the relationship between partner testosterone and relationship quality was likewise negative, but the size of the effect was only marginally significant for both commitment and satisfaction.
There were no significant correlations, for either gender, between partner testosterone levels and relationship investment.
The study authors say there is no way to know whether it is lower testosterone levels that cause better relationships or good relationships that cause testosterone levels to fall, or even some third factor that accounts for both. Further research will be needed to answer such questions.
Still, they say, their work contains several significant findings.
“Testosterone has previously been associated with men's relationship quality (eg, Booth and Dabbs, 1993; Julian and McKenry, 1989), but to our knowledge, the current study is the ï¬rst to demonstrate similar associations among women,” they wrote.
“Our ï¬ndings also provide novel evidence that an individual's relationship quality is negatively associated with his or her partner's testosterone levels, and that such associations are stronger among men than women.”