Male hypogonadism is the inability of the testicles to produce testosterone, sperm or both. The condition also is known as testosterone deficiency.

As part of their reproductive systems, men have external genital organs called testicles (testes). These two oval-shaped organs reside in a pouch of skin (scrotum) that hangs below the abdomen and behind the penis. In addition to producing the sperm cells that are used in reproduction, the testicles secrete the male hormone testosterone. This hormone plays an important role in the development and maintenance of typical masculine physical characteristics.

During fetal development, testosterone is necessary to form male genital organs. During puberty, testosterone is essential for the development of secondary sexual characteristics, such as facial hair, greater muscle mass and a deeper voice. In adult males, testosterone maintains muscle mass and strength, fat distribution, bone mass, sperm production, sex drive and potency.

Treatment of male hypogonadism depends on the cause and may involve testosterone replacement therapy. Hypogonadism affects approximately one in 500 males.

Signs and symptoms

The effects of male hypogonadism depend primarily on the stage of life at which they occur. They can occur during fetal development, puberty or adulthood. During each of these stages, the signs and symptoms are distinct.

Fetal development
The sex chromosomes X and Y — you receive an X from your mother and either an X or a Y from your father — determine whether the gonads in an embryo develop into ovaries (XX) or testicles (XY). If testicles form, the hormone testosterone is produced and male sex organs develop.

Production of too little hormone by the gonads during early fetal development may impair the growth or functions of the internal and external sex organs. This can cause a condition in which the sex of the child is not clear by external examination at birth (ambiguous genitalia).

Puberty
Male hypogonadism present at the time of puberty may slow growth and affect normal development. Body changes may include:

• 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)

The male hormone testosterone plays an important role in the development and maintenance of typical masculine physical characteristics....

Adulthood
Hypogonadism in adult males may alter certain masculine physical characteristics and impair normal reproductive function. Signs and symptoms may include:

• Erectile dysfunction

• Infertility

• Decrease in beard and body hair growth

• Increase in body fat

• Decrease in size or firmness of testicles

• Decrease in muscle mass

• Development of breast tissue

• Loss of bone mass (osteoporosis)

Mental and emotional changes also can accompany hypogonadism. As testosterone decreases, some men may experience symptoms similar to those of menopause in women. These may include:

Causes

Hypogonadism is the absence of testosterone production by the gonads — the testicles in men and the ovaries in women. These sex organs produce the hormones testosterone and estrogen, which ultimately determine the differences between men and women. The two basic types of male hypogonadism are:

• Primary. This type of hypogonadism — also known as primary testicular failure — originates from an abnormality in the testicles.

• Secondary. This type of hypogonadism indicates a defect in the brain or in the pituitary gland that's connected to the brain and that controls hormone production. If chemical messages from the pituitary gland to the testicles aren't sent, impaired testicular function occurs.

The pituitary gland is located within the brain and controls hormone production....

Male hypogonadism can have many causes. Certain diseases and other malfunctions of the testicles or pituitary gland can cause testosterone deficiency.

Common causes of primary hypogonadism include:

• Klinefelter's syndrome. This condition results from a congenital abnormality of the sex chromosomes, X and Y. A male normally has only one X and one Y chromosome. In Klinefelter's 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's syndrome causes abnormal development of the testicles. This condition is present in about 1 in 800 live male births.

• Undescended testicles. Before birth, the testicles develop inside the male infant's abdomen and normally move down into their permanent place in the scrotum 2 months before birth. 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. A boy born with an undescended testicle has a higher risk of infertility and testicular cancer.

• 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.

• Hemochromatosis. Too much iron in the blood can cause testicular failure or pituitary gland dysfunction.

• 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.

• Prior hernia surgery. The vascular supply to the testicles can be damaged during hernia repair surgery. Additional surgery may often correct this problem, restoring testosterone and sperm 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. After age 30, there's a slow and continuous decrease in testosterone production. The rate that testosterone declines varies greatly among individual men. About 15 percent to 30 percent of older men have a testosterone level that's below normal.

In secondary hypogonadism, the testicles are normal but function improperly due to lack of stimulation by the pituitary hormones. Specific causes include:

• Kallmann's syndrome. Defective development of the hypothalamus — the area of the brain that controls the secretion of pituitary hormones — can cause hypogonadism. Impaired release of hormones by the hypothalamus causes inadequate secretion of pituitary and testicular hormones, resulting in testosterone deficiency. This abnormality is also associated with impaired development of the olfactory nerves at the front of the brain, causing the inability to smell (anosmia). Other associated conditions include poor color vision and cleft palate.

• 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. Head trauma resulting in pituitary dysfunction may be a cause. A pituitary tumor or other types of brain tumors located near the pituitary gland may cause testosterone or other hormone deficiencies.

• Inflammatory disease. Certain inflammatory diseases such as sarcoidosis involving the pituitary gland can affect testosterone production and cause hypogonadism.

• Medications. The use of certain drugs can affect testosterone production. Some psychiatric drugs and medications taken for heartburn or gastroesophageal reflux disease (GERD) may cause hypogonadism.

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Risk factors

Risk factors for hypogonadism include:

• Kallmann's syndrome

• Undescended testicles as an infant

• Mumps infection affecting your testicles

• Prior hernia repair

• Prior trauma to your testicles

• Infertility

• Decreased sex drive

• Erectile dysfunction

• Hemochromatosis

Hypogonadism can be hereditary. If any of these risk factors are in your family health history, inform your doctor. Be aware of and watch for signs and symptoms of hypogonadism.

When to seek medical advice

See a doctor if you or your child has any signs or symptoms of male hypogonadism. Establishing the cause of hypogonadism is an important first step to getting appropriate treatment. You or your child may require a consultation with an endocrinologist, a physician who specializes in the hormone-producing (endocrine) glands. If your primary care physician suspects the condition is present, he or she may refer you to an endocrinologist. Or, you may ask for a referral yourself.

Screening and diagnosis

Your doctor may test for decreased testosterone if you have any of the signs or symptoms of hypogonadism. Early detection in boys can help prevent delayed puberty. Early diagnosis and treatment in adult 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 laboratory 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 and 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.

Complications

The complications of untreated hypogonadism differ depending on the age of onset. If hypogonadism occurs during fetal development, a baby may be born with ambiguous genitalia. If hypogonadism develops before puberty, a lack of body hair and impaired penis and testicle growth may occur. Infertility, erectile dysfunction, decreased sex drive, fatigue, muscle loss or weakness, enlarged male breasts, decreased beard and body hair growth, and osteoporosis are possible complications of hypogonadism.

Treatment

Treatment for male hypogonadism depends on the cause and if you're concerned about fertility.

For hypogonadism caused by testicular failure, doctors use male hormone replacement (testosterone replacement therapy, or TRT). Although there's often no effective treatment to restore fertility in a man with primary hypogonadism, assisted reproductive technology (ART) may be helpful. ART covers a variety of techniques designed to help couples who have been unsuccessful achieve conception.

If a pituitary problem is the cause, pituitary hormones may succeed in stimulating sperm production and restoring fertility. TRT can be used if fertility is not an issue. A pituitary tumor may require surgical removal, medication or the replacement of other hormones.

In boys, TRT can stimulate puberty and the development of secondary sex characteristics, such as increased muscle mass, beard and pubic hair growth, and growth of the penis. Pituitary hormones may be used to stimulate testicle growth. An initial low dose of testosterone with gradual increases may help to avoid adverse psychological effects.

In adult men, TRT can restore sexual function and muscle strength and prevent bone loss. In addition, men receiving TRT often experience an increase in energy, sex drive and well-being. Some anti-aging enthusiasts claim that increasing the level of testosterone in older men improves energy, well-being and sex drive, but such claims remain unproved. High doses of testosterone may result in prostate problems, elevated cholesterol and infertility. The long-term benefits or risks of TRT in healthy older men are unclear.

Several testosterone delivery methods exist. Choosing a specific therapy depends on your preference of a particular delivery system, the side effects and the cost. Methods include:

Injection
Intramuscular testosterone injections are safe and effective. Injections are given approximately every 2 weeks. You may experience fluctuations in symptom relief between doses. You or a family member can learn to administer this method of TRT at home. If you're uncomfortable doing this, a nurse or doctor can give the injection.

Patch

• Scrotal patch (Testoderm). Thin scrotal skin is much more permeable to testosterone absorption than other skin sites. You apply this patch in the morning and remove it before bathing or sexual intercourse. Itching and skin irritation can occur, but they're usually mild and diminish with continued use.

• Nonscrotal patch (Androderm). This patch is applied each night to your back, abdomen, upper arm or thigh. The site of the application is rotated to maintain 7-day intervals between applications to the same site. Up to 50 percent of men experience some skin reaction to this product, with approximately 7 percent having a severe reaction.

Gel
You rub testosterone gel (AndroGel, Testim) into your skin on your lower abdomen, upper arm or shoulder. As the gel dries, your body absorbs testosterone through your skin. Avoid showering or bathing for several hours after an application to ensure adequate absorption. A potential side effect of the gel is the possibility of transferring the medication to your partner. You can avoid this by waiting approximately 5 hours after an application or covering the area before having skin-to-skin contact.

Gum and cheek (buccal cavity)
Striant, a small putty-like substance, delivers testosterone through the natural depression above your top teeth where your gum meets your upper lip (buccal cavity). This product rapidly adheres to your gumline and, as exposed to saliva, softens into a gel-like form, allowing testosterone to be absorbed directly into your bloodstream.

Orally
Taking testosterone orally is now rare. Testosterone taken by this method may increase your risk of high cholesterol, blood clots, and heart and liver problems.

Coping skills

Adolescents with hypogonadism may have problems fitting in socially due to delayed sexual development. Testosterone replacement therapy can induce puberty, and at a slow pace, to allow time for adjustment to body changes and new feelings.

If hypogonadism occurs during adulthood, make lifestyle and dietary changes to prevent osteoporosis. Regular exercise and adequate amounts of calcium and vitamin D to maintain bone strength are important to reduce the risk of osteoporosis.

Men may experience psychological and relationship problems due to erectile dysfunction or infertility caused by hypogonadism. Know what to expect from these conditions and what to do if new or uncomfortable feelings develop between you and your partner. Talk with your doctor about how you can reduce the anxiety and stress that often accompany these conditions.

A supportive family that understands the diagnosis of hypogonadism is important. You may need psychological or family counseling. Support groups can help people with hypogonadism and related conditions cope with similar situations and challenges.