Testosterone is often considered one of the most important male hormones. It is made in the testes and secreted into the bloodstream. Some testosterone is also made in the adrenal glands, which are organs located above the kidneys. However, in men, the majority of the testosterone is from the testes. It is responsible for muscle mass, male distribution of body hair, and is important for energy and memory.

Testosterone is known to decline with age. In addition, the presence of other diseases such as diabetes, obesity, and heart disease can also predispose to having low testosterone.

Symptoms of low energy, low libido, poor erections, decreased muscle mass and forgetfulness can be suggestive of low testosterone. However, to make a diagnosis of low testosterone, blood tests are needed to measure the level of testosterone in the blood. For best accuracy, these tests should be collected before 10 am.


Testosterone replacement therapy is the most common method to treat low testosterone. Testosterone can be given as an injection, as a gel, as a pellet implanted in the office, or as a patch. Future blood tests are also usually necessary prior to initiating therapy as well as for those patients already being treated.

The benefits of testosterone treatment may include improvements in energy, libido, erection quality, better memory and increased muscle mass.

Patients who have cancer of the prostate, or are suspected to have cancer of the prostate should not use testosterone replacement. Testosterone replacement may cause elevated red blood cell counts, impairment of fertility, liver dysfunction or exacerbation of heart failure.