How Much Can We Blame Testosterone for Men's Many, Many, Many Faults?

For men, testosterone appears to be somewhat of a double-edged sword. Below-average quantities of the male sex hormone can lead to erectile dysfunction, low fertility, fatigue, and depression. Extremely high levels of testosterone are commonly associated with rage and aggression. And, although normal testosterone levels are necessary for the healthy development of men's physical traits, studies insist that the hormone is linked to a host of negative social behaviors.

Most recently, researchers at the University of Connecticut found that men are less likely to talk after sex—and testosterone is to blame. The study, published in the Journal of Social and Personal Relationships, asked 253 participants to provide saliva samples—which would later be tested for testosterone—and to keep a sex diary over a two-week period. The researchers discovered that individuals with high levels of testosterone viewed "disclosing thoughts and feelings to one's partner after sexual activity" as more risky and less beneficial.

Previous research has blamed the hormone for worse. Because of testosterone, studies show, men are less happy than women, are less verbally adept, and more likely to engage in risky financial behavior; entire financial market crashes have been blamed on the hormone. Testosterone has also been shown to decrease empathy and the ability to fight off infections.

Testosterone, according to endocrinologist Bradley Anawalt, is "the hormone of desire" that sets the stage for normal sexual function in men. Beyond that, he says, "it's a complicated topic." He is skeptical of studies, like the previously mentioned "pillow talk" report, that attribute testosterone to socially detrimental acts. While testosterone levels vary between individuals, the hormone's impact on behavior isn't significant unless it is extremely high or extremely low, he explains. In other words, testosterone alone doesn't indicate how a person is going to act, after sex or otherwise.

Anawalt says that testosterone is most impactful on behavior before birth, and this can partially explain divergence between the sexes when it comes to certain behaviors. "The best way to understand behavioral differences between men and women is to focus first on the notion that there are fundamental differences in the limbic system, which regulates emotions," he tells Broadly. He points to the amygdala, a specific area in the brain that "acts as the center for unpleasant or aggressive emotions."

"Biological men have a larger amygdala in women, and this may be because of the levels of testosterone present when babies are in utero," Anawalt explains. "That's probably the most important difference between prototypical male behavior and prototypical female behavior. I'm speaking in broad generalizations, but, you know—wars tend to be created by men and not women."

But that's not all testosterone's fault, he underlines. While injections of the hormone can have acute effects—like steroid abuse, for example—"there has generally been very poor correlation between testosterone levels at baseline and behavioral aspects," he says. "Natural, existing testosterone levels just don't correlate with longterm behavioral patterns."