It is administered through the skin for treatment of low testosterone levels. It belongs to a class of drugs called androgens. Other testosterone replacement products include Androderm, Axiron, Testim, and Fortesta. Testosterone is the major male sex hormone responsible for the normal growth and development of the male sex organs and secondary sex characteristics. These effects include development of the prostate, penis, and scrotum; distribution of facial, pubic, chest and axillary hair; development of a deep voice and alterations in muscle mass and fat distribution.