Testosterone is an important hormone for healthy libido and sexual function, but it is also imperative for maintaining a healthy body composition and lean body mass. Having healthy levels of testosterone has also been linked to maintaining healthy blood cholesterol levels as well as emotional balance and motivation/drive. Adequate testosterone is also essential for healthy bone metabolism.
The frontal lobe of the brain, our emotional control center and the essence of our personality, has more receptor sites for testosterone in men than the female brain (the female brain has more receptors for estrogen in the frontal lobe). If testosterone levels are low, men will experience less emotion, less motivation/drive, and may suffer from depression. Testosterone also affects dopamine receptors in the nervous system of men which can make life feel colorless when testosterone levels are low.