Intrinsa works by releasing testosterone, the male hormone through the skin into the bloodstream. Testosterone is natural in women, and is produced by the ovaries and adrenal glands. However, the levels of the hormone decline with age, sometimes dramatically after menopause or after hysterectomy.  Testosterone therapy is systemic and needs to be implemented over a period of weeks or months to have a noticeable effect.   P & G licensed for the treatment of Watson Pharmaceuticals.