There’s no reliable evidence that testosterone makes men aggressive, but it may boost happiness, memory, allure, and even honesty, according to intriguing new research.
In a new study, German researchers gave 46 healthy men testosterone gel, while another 45 men received a placebo. The next day, all of the men were asked to roll dice in private and enter their results on a computer. They were given cash payouts based on their scores, with the high rollers getting more money.
Those treated with testosterone gel were significantly less likely to lie about their scores, according to a new study published in PLos One. The scientists theorize that the male hormone enhances men’s sense of pride and self-worth. “This result clearly contradicts the one-dimensional [belief] that testosterone results in anti-social behavior,” said researcher Dr. Armin Falk.
Here’s a look at some of the other hidden powers of testosterone (T) and how it affects both men and women:
It makes men babe magnets. In another recent study, researchers from Wayne State University measured 76 men’s testosterone levels, then asked the men to compete in pairs for the attention of an attractive woman during a seven-minute conversation. Men with high T were more assertive, took control of the conversation, and were much more likely to click with the woman, compared to men with lower T, the study found.
“Books, film, and television often portray men who are bold and self-assured with women as being high in testosterone. Our results suggest that there’s a kernel of truth to this stereotype; that naturally circulating testosterone indeed is associated with men's behaviors when they try to woo women.” study author Richard Slatcher, PhD reports.
Testosterone doesn’t inevitably wane with age. A landmark new study shows that men can maintain youthful levels of T well into old age—if they’re in excellent health. Previously, conventional thinking held that levels of the male hormone inevitably started to drop by up to one percent a year once men reached middle age.
The Healthy Man Study, published in Clinical Endocrinology, found “no decrease associated with age among men over 40 who self-report very good or excellent health.” However, both obesity and smoking were linked with lower T in the 325 men who were studied, suggesting that declining health, rather than age alone, could be the main reason why some older men may experience a hormonal decline.
Low T harms women’s health. Healthy young women have 10 times as much circulating testosterone as they do the female hormone estradiol, according to a new report by the American Society for Reproductive Medicine. Along with playing a crucial role in women’s libido, T also influences women’s bone mass—and a deficiency ups risk for fractures after menopause. A large study also linked low T in women to higher risk for heart attacks and other coronary events, the report states.
In both men and women, testosterone is also thought to have beneficial effects on mental function. According to Harvard Medical School, people with higher T levels in midlife appear to have better brain health; in older men, more testosterone has been linked to better scores on mental tests. Conversely, some studies link reduced levels to impaired mental function. Some research suggests that testosterone therapy may spark subtle improved memory in older people, but evidence is limited.
Slimming down boosts men’s levels. Nearly 50 percent of overweight men with lower T had improved levels of the male hormone after they lost weight, according a recent study of nearly 900 middle-aged, prediabetic men presented at the Endocrine Society’s 2012 annual meeting. None of the men had been diagnosed with hypogonadism (low T), but the researchers found that 20 to 25 percent of the men had below normal levels of the male hormone.
The study randomly assigned the men to be treated with lifestyle modification (exercise and a reduced calorie diet), diabetes medicine, or placebo pills. In the lifestyle group, the rate of men with low T fell from about 20 percent to 11 percent after the men dropped pounds, while there was no change in hormone levels in the other two groups.
Falling in love raises testosterone in women. A small Italian study published in New Scientist found that during a new romance, women’s levels of testosterone rise, while men’s drop, so the two partners become more like each other. The study compared people who had fallen in love during the previous six months to people who were single or in a long-term relationship. However, the hormonal effect was temporary: When the same couples were retested two years later—and no longer madly in love—their testosterone levels had returned to normal.
Hands are influenced by hormones. In men and boys, the right index finger is typically shorter relative to the right ring finger than it is in females. What’s more, this sex-linked difference has even been found in the paws of animals, including rats, and is believed to result from in utero exposure to testosterone.
Hormones may not be the root cause of baldness. Almost all studies of male pattern baldness have focused on the role of testosterone, but new research shows that scientists may be blaming the wrong culprit. A 2012 study reported that bald men have abnormal levels of a protein called prostaglandin D2 (PGD2) on their scalps—a finding that may lead to new therapies that block this protein. The research was published in Science Translational Medicine. The scientists also linked PGD2 to hair loss in older women.
Testosterone boosts men’s mood. Researchers analyzed medical records of 278 men ages 45 and older with no prior diagnosis of depression and found that men with hypogonadism (testosterone deficiency) were more than four times more likely to be diagnosed with depression during the two-year study, compared to men with normal T levels, even after age, alcohol use, prostate cancer, and other medical conditions were taken into account.
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