PCOS is primarily caused by too much sugar and refined carbs in the diet, which creates chronically elevated insulin levels, which stimulates the ovaries to overproduce testosterone, which causes ovarian cysts, excess hair growth etc. For most women, dramatically reducing refined carbs and sugar, and getting some exercise will clear up PCOS in a matter of months. This is why conventional doctors use diabetes drugs to treat PCOS, but that doesn't address the root cause. http://articles.mercola.com/sites/articles/archive/2011/09/18/oral-progesterone-and-progesterone-cream-complications.aspx