Testosterone improves mood, cognitive function and prevents Alzheimer’s disease, stroke, heart failure, and some abnormalities of cholesterol. Testosterone improves libido and erectile function (but not in everyone). It also – in both men and women – reduces inflammation and pain. The diagnosis is made from the symptoms and problems the man has, along with a blood test. The doctor may need up to three blood tests to be sure because the results can vary. When in doubt about the diagnosis, look at the person – do they have any symptoms or problems�already?