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What is Hypogonadism?

Male hypogonadism is a condition in which the body doesn't produce enough testosterone.

Why Should You Care:

Hypogonadism affects an estimated 4 to 5 million men in the United States, and although it may occur in men at any age, low testosterone levels are especially common in older males. More than 60% of men over age 65 have free testosterone levels below the normal values of men aged 30 to 35.

Studies suggest that hypogonadism in adult men is often under diagnosed and under treated.


Symptoms develop dependent upon the stage of development of the disease.

Fetal development:

  • Female genitals
    • Ambiguous genitals — genitals that are neither clearly male nor clearly female
    • Underdeveloped male genitals


  • 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)


  • Erectile dysfunction
  • Infertility
  • Decrease in beard and body hair growth
  • Decrease in muscle mass
  • Development of breast tissue (gynecomastia)
  • Loss of bone mass (osteoporosis)
  • Fatigue
  • Decreased sex drive
  • Difficulty concentrating
  • Hot flashes


Primary hypogonadism: This type of hypogonadism, also known as primary testicular failure, originates from a problem in the testicles.

Common causes of primary hypogonadism include:

  • Klinefelter syndrome: This condition results from a congenital abnormality of the sex chromosomes - X and Y. 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.
  • Mumps orchitis: If a mumps infection involving the testicles in addition to the salivary glands (mumps orchitis) occurs.
  • Hemochromatosis: Too much iron in the blood can cause testicular failure or pituitary gland dysfunction, affecting testosterone production.
  • Injury to the testicles: Because they're situated outside the abdomen, the testicles are prone to injury.
  • Cancer treatment: Chemotherapy or radiation therapy for the treatment of cancer can interfere with testosterone and sperm production.

Secondary hypogonadism: 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.
  • 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.
  • Inflammatory disease: Certain inflammatory diseases, such as sarcoidosis, histiocytosis, and tuberculosis.
  • HIV/AIDS: 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.
  • Normal aging: Older men generally have lower testosterone levels than younger men do.
  • Concurrent illness: The reproductive system can temporarily shut down due to the physical stress of an illness or surgery, as well as during significant emotional stress.

Risk Factors:

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
  • Hemochromatosis
  • Previous chemotherapy or radiation therapy
  • Untreated sleep apnea

Hypogonadism can be inherited.


Treatment for boys:

In boys, testosterone replacement therapy (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 effects and more closely mimic the slow increase in testosterone that occurs during puberty.

Types of testosterone replacement therapy: 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: Testosterone injections (testosterone cypionate, testosterone enanthate) are safe and effective.
  • Patch: A patch containing testosterone (Androderm) is applied each night to your back, abdomen, upper arm, or thigh.
  • Gel: There are several gel preparations available with different ways of applying them. Depending on the brand, you either rub testosterone gel into your skin on your upper arm or shoulder (AndroGel, Testim, Vogelxo), apply with an applicator under each armpit (Axiron), or pump on your front and inner thigh (Fortesta).
  • Gum and cheek (buccal cavity): A small putty-like substance, gum and cheek testosterone replacement (Striant) delivers testosterone through the natural depression above your top teeth where your gum meets your upper lip (buccal cavity). This product quickly sticks to your gumline and allows testosterone to be absorbed into your bloodstream.
  • Nasal: Testosterone can be pumped into the nostrils as a gel.
  • Implantable pellets: Testosterone-containing pellets (Testopel) are surgically implanted under the skin every three to six months.

Oral testosterone isn't recommended for long-term hormone replacement because it might cause liver problems.


The complications of untreated hypogonadism differ depending on what age it first develops — during fetal development, puberty, or adulthood.

Fetal development: A baby may be born with:

  • Ambiguous genitalia
  • Abnormal genitalia

Puberty: Pubertal development can be delayed or incomplete, resulting in:

  • Diminished or lack of beard and body hair
  • Impaired penis and testicle growth
  • Disproportional growth, usually increased length of arms and legs compared with the trunk
  • Enlarged male breasts (gynecomastia)

Adulthood: Complications may include:

  • Infertility
  • Decreased sex drive
  • Fatigue
  • Muscle loss or weakness
  • Enlarged male breasts (gynecomastia)
  • Decreased beard and body hair growth
  • Osteoporosis


Carries various risks, including contributing to:

  • Sleep apnea
  • Stimulating noncancerous growth of the prostate
  • Enlarging breasts, limiting sperm production
  • Heart attack
  • Stimulating growth of existing prostate cancer
  • Blood clots forming in the veins


* CIS does not provide medical advice, diagnosis or treatment. The content is for informational purposes only. 

Dr. Eva Agaiby

President, Director of Clinical Trials & Regulatory Affairs

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Director of Marketing & Business Development

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