There are two types of testosterone deficiency. Primary testosterone deficiency is the failure of testicles to produce adequate amounts of the hormone. Secondary testosterone deficiency involves failure of the pituitary gland to send proper signals from the brain to the testicles.
Normal aging can cause primary testosterone deficiency as can autoimmune disorders (such as Addison's disease and hypoparathyroidism), genetic disorders (such as Turner and Klinefelter syndromes), infections, liver and kidney disease, hemochromatosis (the body absorbing too much iron), radiation exposure, injury to or surgery on sex organs, stress, alcoholism and cancer treatments.
Secondary testosterone deficiency may be caused by obesity, HIV/AIDS, inflammatory diseases (such as sarcoidosis, tuberculosis), pain and hormone medications, pituitary disorders, Kallmann syndrome, rapid weight loss, nutritional deficiencies, bleeding and brain surgery.
A visit to the doctor and blood tests can determine if you have a testosterone deficiency. It may be necessary to have more than one blood test because testosterone levels fluctuate during the day. Doctors usually prefer testing in the morning when levels are highest. Testosterone levels less than 300 nanograms per deciliter (ng/dL) can indicate low testosterone.
Some researchers have found that a change in lifestyle, including diet and exercise, offer a solution to low testosterone. However, if medical treatment is required, there are several options.
Each of the treatments above offers different levels of testosterone replacement, and has advantages and disadvantages. The treatment best suited for you will be determined by you and your doctor.