What is it?
Male hypogonadism is a condition in which the body doesn't produce enough of the hormone testosterone — the hormone that plays a key role in masculine growth and development during puberty.
You may be born with male hypogonadism, or it can develop later in life from injury or infection. The effects — and what you can do about them — depend on the cause and at what point in your life male hypogonadism occurs. Some types of male hypogonadism can be treated with testosterone replacement therapy.
Hypogonadism can occur during fetal development, puberty or adulthood. Depending on when it develops, the signs and symptoms differ.
If the body doesn't produce enough testosterone during fetal development, the result may be impaired growth of the external sex organs. Depending on when it develops, and how much testosterone is present, a child who is genetically male may be born with:
- Female genitals
- Ambiguous genitals — genitals that are neither clearly male nor clearly female
- Underdeveloped male genitals
During puberty, male hypogonadism may slow growth and affect development. It can cause:
- Decreased development of muscle mass
- Lack of deepening of the voice
- Impaired growth of body hair
- Impaired growth of the penis and testicles
- Excessive growth of the arms and legs in relation to the trunk of the body
- Development of breast tissue (gynecomastia)
In adult males, hypogonadism may alter certain masculine physical characteristics and impair normal reproductive function. Signs and symptoms may include:
- Erectile dysfunction
- Decrease in beard and body hair growth
- Decrease in muscle mass
- Development of breast tissue (gynecomastia)
- Loss of bone mass (osteoporosis)
Hypogonadism can also cause mental and emotional changes. As testosterone decreases, some men may experience symptoms similar to those of menopause in women. These may include:
- Decreased sex drive
- Difficulty concentrating
- Hot flashes
Male hypogonadism means the testicles don't produce enough of the male sex hormone testosterone. There are two 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. The hypothalamus produces gonadotropin-releasing hormone, which signals the pituitary gland to make follicle-stimulating hormone (FSH) and luteinizing hormone. Luteinizing hormone then signals the testes to produce testosterone.
Either type of hypogonadism may be caused by an inherited (congenital) trait or something that happens later in life (acquired), such as an injury or an infection.
Common causes of primary hypogonadism include:
- Klinefelter syndrome. This condition results from a congenital abnormality of the sex chromosomes, X and Y. A male normally has one X and one Y chromosome. In Klinefelter syndrome, two or more X chromosomes are present in addition to one Y chromosome. The Y chromosome contains the genetic material that determines the sex of a child and related development. The extra X chromosome that occurs in Klinefelter syndrome causes abnormal development of the testicles, which in turn results in underproduction of testosterone.
- Undescended testicles. Before birth, the testicles develop inside the abdomen and normally move down into their permanent place in the scrotum. Sometimes, one or both of the testicles may not be descended at birth. This condition often corrects itself within the first few years of life without treatment. If not corrected in early childhood, it may lead to malfunction of the testicles and reduced production of testosterone.
- Mumps orchitis. If a mumps infection involving the testicles in addition to the salivary glands (mumps orchitis) occurs during adolescence or adulthood, long-term testicular damage may occur. This may affect normal testicular function and testosterone production.
- Haemochromatosis. Too much iron in the blood can cause testicular failure or pituitary gland dysfunction affecting testosterone production.
- Injury to the testicles. Because of their location outside the abdomen, the testicles are prone to injury. Damage to normally developed testicles can cause hypogonadism. Damage to one testicle may not impair testosterone production.
- Cancer treatment. Chemotherapy or radiation therapy for the treatment of cancer can interfere with testosterone and sperm production. The effects of both treatments often are temporary, but permanent infertility may occur. Although many men regain their fertility within a few months after treatment ends, preserving sperm before starting cancer therapy is an option that many men consider.
- Normal aging. Older men generally have lower testosterone levels than younger men do. As men age, there's a slow and continuous decrease in testosterone production. The rate that testosterone declines varies greatly among men. As many as 30 percent of men older than 75 have a testosterone level that's below normal, according to the American Association of Clinical Endocrinologists. Whether or not treatment is necessary remains a matter of debate.
In secondary hypogonadism, the testicles are normal but function improperly due to a problem with the pituitary or hypothalamus. A number of conditions can cause secondary hypogonadism, including:
- Kallmann syndrome. Abnormal development of the hypothalamus — the area of the brain that controls the secretion of pituitary hormones — can cause hypogonadism. This abnormality is also associated with impaired development of the ability to smell (anosmia).
- Pituitary disorders. An abnormality in the pituitary gland can impair the release of hormones from the pituitary gland to the testicles, affecting normal testosterone production. A pituitary tumor or other type of brain tumor located near the pituitary gland may cause testosterone or other hormone deficiencies. Also, the treatment for a brain tumor such as surgery or radiation therapy may impair pituitary function and cause hypogonadism.
- Inflammatory disease. Certain inflammatory diseases such as sarcoidosis, histiocytosis and tuberculosis involve the hypothalmus and pituitary gland and can affect testosterone production, causing hypogonadism.
- HIV/AIDS. This virus can cause low levels of testosterone by affecting the hypothalamus, the pituitary and the testes.
- Medications. The use of certain drugs, such as opiate pain medications and some hormones, can affect testosterone production.
- Obesity. Being significantly overweight at any age may be linked to hypogonadism.
Risk factors for hypogonadism include:
- Kallmann syndrome
- Undescended testicles as an infant
- Mumps infection affecting your testicles
- Injury to your testicles
- Testicular or pituitary tumors
- Klinefelter syndrome
- Previous chemotherapy or radiation therapy
Hypogonadism can be inherited. If any of these risk factors are in your family health history, tell your doctor.
The complications of untreated hypogonadism differ depending on what age it first develops — during fetal development, puberty or adulthood:
- Fetal development. If hypogonadism begins during fetal development, a baby may be born with ambiguous or abnormal genitalia.
- Puberty. If hypogonadism develops before puberty, a lack of body hair and impaired penis and testicle growth may occur.
- Adulthood. Infertility, erectile dysfunction, decreased sex drive, fatigue, muscle loss or weakness, enlarged male breasts (gynecomastia), decreased beard and body hair growth, and osteoporosis are possible complications of hypogonadism in adults.
Your doctor may test your blood level of testosterone if you have any of the signs or symptoms of hypogonadism. Early detection in boys can help prevent problems from delayed puberty. Early diagnosis and treatment in men offers better protection against osteoporosis and other related conditions.
Doctors base a diagnosis of hypogonadism on symptoms and results of blood tests that measure testosterone levels. Because testosterone levels vary and are generally highest in the morning, blood testing is usually done early in the day.
If tests confirm you have low testosterone, further testing can determine if a testicular disorder or a pituitary abnormality is the cause. Based on specific signs and symptoms, additional studies can pinpoint the cause. These studies may include:
- Hormone testing
- Semen analysis
- Pituitary imaging
- Genetic studies
- Testicular biopsy
Testosterone testing also plays an important role in managing hypogonadism. This helps your doctor determine the right dosage of medication, both initially and over time.