What are the causes of hypogonadism in men? Male hypogonadism occurs when a man’s testicles (testicles) do not produce enough of the male sex hormone testosterone. There are mainly two types of hypogonadism: Primary. This type of hypogonadism, also known as primary testicular failure (decreased production of sperm and male sex hormones from the testicles) originates from a problem in the testicles; Secondary. This type of hypogonadism is caused by a problem in the hypothalamus or 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 produce follicle-stimulating hormone (FSH) and luteinizing hormone (LH). Luteinizing hormone then signals the testicles to produce testosterone. Both types of hypogonadism can be inherited (congenital) or acquired later in life due to injury or infection. Sometimes primary and secondary hypogonadism occur together. Primary hypogonadism Common causes of primary hypogonadism include: Klinefelter syndrome. This condition results from a congenital abnormality of the sex chromosomes X and Y. A male usually has one X and one Y chromosome. In Klinefelter syndrome, two or more X chromosomes are present in addition to the Y chromosome. The Y chromosome contains the genetic material that determines the baby’s sex and related development. The extra X chromosome that occurs in Klinefelter syndrome causes the testicles to develop abnormally, which in turn leads to insufficient testosterone production. Undescended testicles (cryptorchidism). Before birth, the testicles develop inside the abdomen and usually move down to their permanent location in the scrotum. Sometimes one or both testicles do not descend at birth. This condition often corrects in the first few years of life without treatment. If not corrected in early childhood, it can lead to testicular dysfunction and decreased testosterone production. Mumps orchitis. A mumps infection affecting the testicles that occurs during adolescence or adulthood can damage the testicles, affecting their function and testosterone production. Hemochromatosis. Too high levels of iron in the blood can cause testicular failure or pituitary gland dysfunction, which affects testosterone production. Testicular injury. Because they are outside the abdomen, the testicles are susceptible to injury. Damage to both testicles can cause hypogonadism. Damage to one testicle may not impair total testosterone production. Cancer treatment. Chemotherapy or radiation therapy to treat cancer can interfere with the production of testosterone and seminal fluid. The effects of both treatments are often temporary,but they can also cause permanent infertility. Although many men regain their fertility within a few months of treatment, preserving sperm (by freezing) before starting cancer therapy is an option for men. Secondary hypogonadism In secondary hypogonadism, the testicles are healthy but do not function properly due to a problem with the pituitary gland or hypothalamus. A number of conditions can cause secondary hypogonadism, such as: Kallmann syndrome. A genetic disorder resulting in abnormal development of the area of ​​the brain that controls the secretion of pituitary hormones (the hypothalamus). This abnormality can also affect the ability to smell (anosmia) and cause red-green color blindness. Pituitary disorders. An abnormality in the pituitary gland can disrupt 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 can cause a deficiency of testosterone or other hormones. Also, brain tumor treatment, such as surgery or radiation therapy, can affect the pituitary gland and cause hypogonadism. Inflammatory disease. Some inflammatory diseases, such as sarcoidosis, histiocytosis, and tuberculosis, affect the hypothalamus and pituitary gland and can affect testosterone production. HIV/AIDS. HIV/AIDS can cause low testosterone levels by affecting the hypothalamus, pituitary gland, and testicles. Medicines. The use of certain medications, such as opioid analgesics and certain hormones, can affect testosterone production. Obesity. Being overweight at any age can be associated with hypogonadism. Aging. As men age, there is a slow, progressive decline in testosterone production. The percentage of men affected varies widely. What are the complications of hypogonadism in men? Complications of untreated hypogonadism differ depending on when the condition occurred—during fetal development, puberty, or adulthood. Complications may include: Abnormal genitalia; Enlarged male breasts (gynecomastia); Infertility; Erectile dysfunction; Osteoporosis References: 1. Snyder PJ. Clinical features and diagnosis of male hypogonadism 2. AskMayoExpert. Male hypogonadism (adult). Mayo Clinic 3. Gardner DG, et al., eds. Testes. In: Greenspan’s Basic and Clinical Endocrinology. 10th ed. 4. Bhasin S, et al. Testosterone therapy in men with hypogonadism: An Endocrine Society clinical practice guideline. The Journal of Clinical Endocrinology and Metabolismbut are not functioning properly due to a problem with the pituitary gland or hypothalamus. A number of conditions can cause secondary hypogonadism, such as: Kallmann syndrome. A genetic disorder resulting in abnormal development of the area of ​​the brain that controls the secretion of pituitary hormones (the hypothalamus). This abnormality can also affect the ability to smell (anosmia) and cause red-green color blindness. Pituitary disorders. An abnormality in the pituitary gland can disrupt 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 can cause a deficiency of testosterone or other hormones. Also, brain tumor treatment, such as surgery or radiation therapy, can affect the pituitary gland and cause hypogonadism. Inflammatory disease. Some inflammatory diseases, such as sarcoidosis, histiocytosis, and tuberculosis, affect the hypothalamus and pituitary gland and can affect testosterone production. HIV/AIDS. HIV/AIDS can cause low testosterone levels by affecting the hypothalamus, pituitary gland, and testicles. Medicines. The use of certain medications, such as opioid analgesics and certain hormones, can affect testosterone production. Obesity. Being overweight at any age can be associated with hypogonadism. Aging. As men age, there is a slow, progressive decline in testosterone production. The percentage of men affected varies widely. What are the complications of hypogonadism in men? Complications of untreated hypogonadism differ depending on when the condition occurred—during fetal development, puberty, or adulthood. Complications may include: Abnormal genitalia; Enlarged male breasts (gynecomastia); Infertility; Erectile dysfunction; Osteoporosis References: 1. Snyder PJ. Clinical features and diagnosis of male hypogonadism 2. AskMayoExpert. Male hypogonadism (adult). Mayo Clinic 3. Gardner DG, et al., eds. Testes. In: Greenspan’s Basic and Clinical Endocrinology. 10th ed. 4. Bhasin S, et al. Testosterone therapy in men with hypogonadism: An Endocrine Society clinical practice guideline. The Journal of Clinical Endocrinology and Metabolismbut are not functioning properly due to a problem with the pituitary gland or hypothalamus. A number of conditions can cause secondary hypogonadism, such as: Kallmann syndrome. A genetic disorder resulting in abnormal development of the area of ​​the brain that controls the secretion of pituitary hormones (the hypothalamus). This abnormality can also affect the ability to smell (anosmia) and cause red-green color blindness. Pituitary disorders. An abnormality in the pituitary gland can disrupt 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 can cause a deficiency of testosterone or other hormones. Also, brain tumor treatment, such as surgery or radiation therapy, can affect the pituitary gland and cause hypogonadism. Inflammatory disease. Some inflammatory diseases, such as sarcoidosis, histiocytosis, and tuberculosis, affect the hypothalamus and pituitary gland and can affect testosterone production. HIV/AIDS. HIV/AIDS can cause low testosterone levels by affecting the hypothalamus, pituitary gland, and testicles. Medicines. The use of certain medications, such as opioid analgesics and certain hormones, can affect testosterone production. Obesity. Being overweight at any age can be associated with hypogonadism. Aging. As men age, there is a slow, progressive decline in testosterone production. The percentage of men affected varies widely. What are the complications of hypogonadism in men? Complications of untreated hypogonadism differ depending on when the condition occurred—during fetal development, puberty, or adulthood. Complications may include: Abnormal genitalia; Enlarged male breasts (gynecomastia); Infertility; Erectile dysfunction; Osteoporosis References: 1. Snyder PJ. Clinical features and diagnosis of male hypogonadism 2. AskMayoExpert. Male hypogonadism (adult). Mayo Clinic 3. Gardner DG, et al., eds. Testes. In: Greenspan’s Basic and Clinical Endocrinology. 10th ed. 4. Bhasin S, et al. Testosterone therapy in men with hypogonadism: An Endocrine Society clinical practice guideline. The Journal of Clinical Endocrinology and Metabolismcan cause a deficiency of testosterone or other hormones. Also, brain tumor treatment, such as surgery or radiation therapy, can affect the pituitary gland and cause hypogonadism. Inflammatory disease. Some inflammatory diseases, such as sarcoidosis, histiocytosis, and tuberculosis, affect the hypothalamus and pituitary gland and can affect testosterone production. HIV/AIDS. HIV/AIDS can cause low testosterone levels by affecting the hypothalamus, pituitary gland, and testicles. Medicines. The use of certain medications, such as opioid analgesics and certain hormones, can affect testosterone production. Obesity. Being overweight at any age can be associated with hypogonadism. Aging. As men age, there is a slow, progressive decline in testosterone production. The percentage of men affected varies widely. What are the complications of hypogonadism in men? Complications of untreated hypogonadism differ depending on when the condition occurred—during fetal development, puberty, or adulthood. Complications may include: Abnormal genitalia; Enlarged male breasts (gynecomastia); Infertility; Erectile dysfunction; Osteoporosis References: 1. Snyder PJ. Clinical features and diagnosis of male hypogonadism 2. AskMayoExpert. Male hypogonadism (adult). Mayo Clinic 3. Gardner DG, et al., eds. Testes. In: Greenspan’s Basic and Clinical Endocrinology. 10th ed. 4. Bhasin S, et al. Testosterone therapy in men with hypogonadism: An Endocrine Society clinical practice guideline. The Journal of Clinical Endocrinology and Metabolismcan cause a deficiency of testosterone or other hormones. Also, brain tumor treatment, such as surgery or radiation therapy, can affect the pituitary gland and cause hypogonadism. Inflammatory disease. Some inflammatory diseases, such as sarcoidosis, histiocytosis, and tuberculosis, affect the hypothalamus and pituitary gland and can affect testosterone production. HIV/AIDS. HIV/AIDS can cause low testosterone levels by affecting the hypothalamus, pituitary gland, and testicles. Medicines. The use of certain medications, such as opioid analgesics and certain hormones, can affect testosterone production. Obesity. Being overweight at any age can be associated with hypogonadism. Aging. As men age, there is a slow, progressive decline in testosterone production. The percentage of men affected varies widely. What are the complications of hypogonadism in men? Complications of untreated hypogonadism differ depending on when the condition occurred—during fetal development, puberty, or adulthood. Complications may include: Abnormal genitalia; Enlarged male breasts (gynecomastia); Infertility; Erectile dysfunction; Osteoporosis References: 1. Snyder PJ. Clinical features and diagnosis of male hypogonadism 2. AskMayoExpert. Male hypogonadism (adult). Mayo Clinic 3. Gardner DG, et al., eds. Testes. In: Greenspan’s Basic and Clinical Endocrinology. 10th ed. 4. Bhasin S, et al. Testosterone therapy in men with hypogonadism: An Endocrine Society clinical practice guideline. The Journal of Clinical Endocrinology and MetabolismMayo Clinic 3. Gardner DG, et al., eds. Testes. In: Greenspan’s Basic and Clinical Endocrinology. 10th ed. 4. Bhasin S, et al. Testosterone therapy in men with hypogonadism: An Endocrine Society clinical practice guideline. The Journal of Clinical Endocrinology and MetabolismMayo Clinic 3. Gardner DG, et al., eds. Testes. In: Greenspan’s Basic and Clinical Endocrinology. 10th ed. 4. Bhasin S, et al. Testosterone therapy in men with hypogonadism: An Endocrine Society clinical practice guideline. The Journal of Clinical Endocrinology and Metabolism