Testosterone is a natural hormone produced in the body, in the testes in men and ovaries in women. While it is used by both sexes, in males the hormone is produced in larger quantities and is primarily responsible for the development of sexual characteristics, for the deepening of the voice and facial hair. Testosterone production is at its peak during puberty or when a boy turns into a man and for a few years thereafter. Testosterone production When a male child is conceived, and testosterone production in the body starts, the hormone is responsible for the development of male genitals even in the fetus. At puberty the hormone production spikes and is responsible for the testes descending, the growth of the penis, the production of sperm and other male characteristics. Testosterone is produced largely in the testes, and in smaller quantities in the adrenal glands. The levels of testosterone are regulated by the hypothalamus which gives the message to the pituitary glands as to ho...