How Testosterone affects male behaviour?

The male hormone is just one factor that affects the behavior but the resultant behavior of a person is a result of the combination of so many factors including environmental conditions and not just his hormones.

Males who have high testosterone usually get angry easily, sometimes for no apparent reason. Anger can also be caused by other psychological problems that have nothing to do with increased testosterone.

A male with high testosterone can experience aggression and hostility especially towards other males. In extreme cases that male could have antisocial behavior. See also signs of high testosterone.

When testosterone goes up a male's sexual desire goes up. Males with high testosterone level think about sex more often. See natural ways to increase testosterone.

In some studies testosterone injections have been associated with reduced fatigue. Males who have low testosterone might feel tired easily.

High testosterone levels can make a male feel less depressed. Male who have low level of testosterone are more likely to get depressed.

Males who get testosterone injections might report increased self esteem. While self esteem is subject to many other factors it seems that there is a connection between it and the levels of testosterone a male has.

Males with high levels of testosterone are usually very competitive. Males who have lower levels of testosterone are usually less competitive than their peers. See also how testosterone levels change during the day.

Testosterone fuels feelings of Protectiveness towards one's female. This protectiveness can be demonstrated in an aggressive way.

In one study it was shown that testosterone fuels stingy and anti social behavior when there is a competition.

The absence of competition lets testosterone function in a different way according to a study. With no competition perceived a male with high testosterone can be friendly and generous.

Testosterone can also fuel the desire to dominate. Dominant males usually have higher levels of testosterone. See how testosterone decreases with age.

Some studies have shown a connection between high levels of testosterone and risk taking behavior.