Please list the specific tests for finding the causes of low testosterone. why don't doctors look first for the cause before administering thw cure?

Low testosterone: Also known as hypogonadism, this condition is diagnosed by blood tests to check hormone levels, and should be done first thing in the morning. In my own practice, I do not and would not administer testosterone replacement therapy without first confirming the diagnosis with lab tests. You may wish to obtain a second opinion if you uncertain about your management.