Testosterone is primarily a male sex hormone which helps us in increasing 
stamina and building body mass. It is secreted in males by testis and in females by ovaries. Some amount of it is also produced by adrenal glands. But the majority of is produced in it as it is a male sex hormone. Deficiency of it can cause impotence, muscle loss, obesity and brittle bones. So its very much necessary specially for males to have a proper balance of testosterone in body. It can be achieved by various means such as by taking steroids or by having any kind of special therapy but it is better to increase its level naturally in the blood stream.