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.