Note
Testosterone is a natural hormone responsible for the normal growth and development of certain male organs and for maintenance of other masculine traits. In men, testosterone is produced in the testes (the reproductive glands that also produce sperm) and regulated by the hypothalamus and pituitary gland. With low testosterone levels, men can experience a decrease in energy and libido, increase in body fat, and emotional changes. A decrease in testosterone levels is to be expected as men age.