Low testosterone levels can occur due to several causes, such as genetic conditions, injuries, or hormonal abnormalities, to name a few. People who have this condition may experience symptoms like depression, fatigue, and increased fat mass. However, blood tests and other testing are needed to make an accurate diagnosis. Treatment will likely involve testosterone replacement medications, which can be quite effective in many cases.
What Is Low Testosterone?Low testosterone (also known as androgen deficiency or male hypogonadism) occurs when the testes do not make enough of the male hormone testosterone. Without enough testosterone, a variety of symptoms can occur.
Although exact estimates vary widely, it appears that low testosterone is fairly common. In one study, 5.6 percent of men age 30 to 79 years old had low testosterone levels that were severe enough to cause symptoms; this risk increased with age.
Although low testosterone is generally thought of as a male condition, there is much interest in studying and perhaps treating the condition in women. However, because the practice of diagnosing and treating testosterone levels in women is fairly new, not well established, and somewhat controversial, this article will focus on low testosterone in men.
The Brain, the Testes, and Low TestosteroneThe testes, also known as testicles, are the male gonads. The primary functions for the testes are to produce testosterone and sperm. The testes produce testosterone in response to hormonal signals from the pituitary gland, which is located in the brainstem. Similarly, the pituitary gland produces its hormones in response to signals from the hypothalamus, which is located higher up in the brain. If anything goes wrong in this process, low testosterone levels can result. Problems can occur early or later in life.
Low testosterone can be caused either directly or indirectly by a variety of different problems, including but not limited to:
- A variety of different genetic conditions
- Certain medications
- Other hormonal abnormalities
- Various chronic illnesses, such as kidney failure or cirrhosis of the liver.
(Click Causes of Low Testosterone to learn more about these conditions, including other possible causes.)