7 Facts You Didn't (But Need To) Know About Testosterone

When you think of testosterone, odds are you think of aggressive, burly, hairy-chested men. And to be fair, the stereotype isn't too far off from the reality: it's the hormone responsible for the growth of prostate and other male sex organs, bulks up body muscle mass and strength, hair, and gives a revving boost to a guy's sex drive.

So while it's important for a man's health, science says that's not the whole story. Here are some other eye-opening facts you probably didn't know about testosterone — in both men and women.

1. Falling In Love Has Opposing Chemical Effects On Men And Women.


While falling head over heels seems to cause a man's T-levels to dip, love seems to have the opposite effect on women. Italian researchers found that a women's levels of testosterone rises while the man's levels drop, so the two partners become more like each other. "Men, in some way, had become more like women, and women had become like men," says lead researcher Donatella Marazziti from the University of Pisa. "It's as if nature wants to eliminate what can be different in men and women, because it's more important to survive [and mate] at this stage." her team concluded that converging levels of testosterone bring lovers together.

2. Losing It Helps Him Become More Of A Family Man.


This fact is actually kind of endearing. In a study, published in Proceedings Of The National Academy Of Sciences, researchers recruited 70 biological fathers of toddlers. Using blood tests, MRI scans of the testes, and feedback from the mothers, they found that "men with lower testosterone levels, were more involved in the day-to-day caregiving of the child," according to associate professor and co-author of the study, James Rilling. The lowered testosterone allows the man to be more sensitive to his child's needs, bond with it and stay loyal to his mate. These results also attest to an evolutionary theory called the "Life History Theory" that suggests that organisms have a finite amount of energy to invest in either mating and parenting strategies.

3. Mo' Money? Mo' Testosterone!

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A team of British scientists have found that men on the trading tend to have higher levels of testosterone when they land big, big profits. They also found that traders who have higher testosterone levels to begin with tend to make more money, suggesting that there's a cause-effect relationship at play. In the animal kingdom, this is something called the " winner effect" where an alpha male produces a surge of testosterone, which in turn helps him to win again in his next conquest. (So kinda ... there are wolves of Wall Street.)

4. Want To Know His T-Levels? Look At His Hands


If you ever wanted to know a guy's testosterone numbers, check out his digits. According to what scientists call the "finger ratio" (also called the 2D:4D because it compares the length of the second digit with the fourth digit of your hand), the difference in length between his right index and ring fingers are determined by the amount of exposure to testosterone he experienced as a fetus in the womb of his mother. The more testosterone in the equation, the more masculine he will be when born.

5. Winning Gives Him A T-Boost.

The Coli

If there's a competitive streak in a guy, chances are he has alot of testosterone coursing through his veins. After the game, the winner's testosterone will increase even more ... and it's not just limited to the winner's circle on the field. Researchers from the University Of Utah conducted a series of experiments to prove the theory that fans experience the same surge of testosterone as their favorite teams. For one, they observed a group of male superfans watching a Brazil vs. Italy World Cup match. The Brazil fans' testosterone levels increased by 20 percent after their team won, while the Italy fans' testosterone fell by 20 percent. Can you say, "Gooooooooooaaal!"

6. Chopping Wood Increases Testosterone By Nearly 50 Percent.


Even better than a sports game, go out back and chop down some trees. The study, published in Evolution and Human Behaviour, found that one hour of tree chopping resulted in a 48 percent increase in salivary testosterone levels in all men, regardless of age or state of health. (So get choppin' guys.)

7. It Has Unexpected Health Benefits For Women.


We tend to think of it as an exclusively masculine benefit, but this hormone has hidden powers for females too. In fact, having low testosterone is not an equivalent to thriving femininity. Low T-levels harms a woman's health. According to a report by the American Society For Reproductive Medicine, healthy young women have 10 times as much testosterone circulating in their bodies as they do the female hormone estradiol. Testosterone keeps your mind sharp, protects your bones and decreases your risk of having a coronary event.