Scientists are uncovering the role testosterone plays in erectile dysfunction, depressin, osteoporosis and even heart disease. It's not only age that can cause the decline in this important hormone. Hypertension, diabetes, treatment for prostate cancer, even stress and anxiety can cause severe testosterone loss. The Testosterone Edge gives readers everything they need to know about boosting testosterone levels both naturally (through herbs, diet and exercise) and medically (through testosterone replacement therapy).