Testosterone is the most important sex hormone in men. Low levels of testosterone production can cause decreased sexual function, loss of male characteristics, and mood changes.
Low Testosterone Overview
Testosterone is the most important sex hormone that men have. It is responsible for the typical male characteristics, such as facial, pubic, and body hair; muscle strength and mass; and a deep voice. Testosterone also helps maintain sex drive and sexual function, sperm production, red blood cell production, and bone health. The brain and pituitary gland (a small gland at the base of the brain) control the production of testosterone by the testes.
In a adult men, low testosterone levels (also called hypogonadism) can cause a decrease in sex drive, poor erections, low sperm count, and enlarged breasts. Over time, low testosterone may cause a man to lose body hair, muscle mass, and strength and to gain body fat. Long-term low testosterone may also cause weak bones (osteoporosis), mood changes, decreased energy, and smaller testes.
A man's testosterone level normally decreases with age. Approximately 4 out of 10 men over the age of 45 have low testosterone levels.Low testosterone can result from injuries, infections, medications, chronic diseases, or genetic conditions. Testosterone replacement therapy can improve symptoms of low testosterone.
Low Testosterone Symptoms
Hypogonadism can begin during fetal development, before puberty, or during adulthood. Signs and symptoms depend on when the condition develops.
If the body does not produce enough testosterone during fetal development, the result may be impaired growth of the external sex organs. Male hypogonadism may delay puberty or cause incomplete or lack of normal development.
In adult males, low levels of testosterone may alter certain masculine physical characteristics and impair normal reproductive function. Signs and symptoms may include:
Low testosterone levels can also cause mental and emotional changes. As testosterone decreases, some men may experience symptoms similar to those of menopause in women, including:
Low Testosterone Causes
Male hypogonadism means the testicles do not produce enough of the male sex hormone testosterone. There are 2 basic types of hypogonadism:
Primary. This type of hypogonadism — also known as primary testicular failure — originates from a problem in the testicles.
Secondary. This type of hypogonadism indicates a problem in the hypothalamus or the pituitary gland — parts of the brain that signal the testicles to produce testosterone.
Possible secondary causes of low testosterone include:
Both primary and secondary hypogonadism may be caused by an inherited (congenital) trait or something that happens later in life (acquired), such as an injury or an infection. At times, primary and secondary hypogonadism can occur together.
Risk factors for hypogonadism include:
Low Testosterone Diagnosis
Doctors base a diagnosis of hypogonadism on physical symptoms and results of blood tests that measure testosterone levels. During a physical exam, your doctor will examine your body hair, size of your breasts and penis, and the size and consistency of the testes and scrotum. Your doctor can also use blood tests to see if your total testosterone level is low. Because testosterone levels vary and are generally highest in the morning, blood testing is usually done early in the day, often between 7 and 10 a.m.
Further testing can determine if a testicular disorder or a pituitary abnormality is the cause. These studies may include:
Early detection of low testosterone production in boys can help prevent problems from delayed puberty. Early diagnosis and treatment in men offer better protection against osteoporosis and other related conditions.
Living With Low Testosterone
Adult men can take several steps to maintain their overall health as they manage low testosterone levels.
Prevent osteoporosis. Lifestyle and dietary changes can help prevent osteoporosis. Regular exercise and adequate amounts of calcium and vitamin D maintain bone strength and are important for reducing the risk of osteoporosis.
Learn about erectile dysfunction or infertility. The conditions caused by low testosterone can cause psychological and relationship problems. Know what to expect from these conditions and what to do if new or uncomfortable feelings develop between you and your partner.
Reduce stress. Talk with your doctor about how you can reduce the anxiety and stress that often accompany these conditions. Many men benefit from psychological or family counseling.
Find support. Support groups can help people with hypogonadism and related conditions cope with similar situations and challenges. Helping your family understand the diagnosis of hypogonadism also is important.
Low Testosterone Treatments
Treatment for male hypogonadism depends on the cause and whether you are concerned about fertility. For adult men, testosterone replacement therapy can improve sexual interest, erections, mood and energy, body hair growth, bone density, and muscle mass.
Testosterone replacement has been shown to:
Testosterone treatment may also increase bone mineral density and lower the risk for broken bones. Testosterone treatment is a life-long therapy, just like in other chronic conditions. Stopping treatment will result in low levels.