Male hypogonadism means the testicles do not produce enough of the male sex hormone testosterone. When levels are low, men might have decreased sex drive, less muscle mass, erectile dysfunction, and fatigue.
Hypogonadism has a negative effect on organ function and quality of life. Testosterone is responsible for male reproductive and sexual functions. It affects puberty, fertility, muscle mass, body composition, bone strength, fat metabolism, sex drive, mood and mental processes (Fig. 1).
Testosterone is an androgen. Production of androgens decreases slightly with age. Low levels are more common in men who are obese and have multiple health conditions.
What does testosterone do?
|Brain||Affects sex drive, mood, and mental processes (cognition)|
|Skin||Affects male pattern body and facial hair, balding, and oil production|
|Larynx||Deepens voice and prompts formation of Adam’s apple|
|Organ||Stimulates production of erythropoietin, which causes red blood cells to form|
|Male sexual organs||Affect penile and prostate growth and function and production of sperm|
|Muscle||Increases strength and muscle mass|
|Liver||Affects production of proteins|
|Fat||Decreases fat mass|
|Bone marrow||Stimulates production of stem cells|
|Bone||Accelerates growth, increases bone strength, and maintains bone density|
Testosterone is produced mainly in the testicles and also by the adrenal glands. Women have testosterone, but in much smaller amounts than men.
In the brain, the hypothalamus and pituitary gland help the testicles produce testosterone. They produce hormones that prompt action in the testicles. In response, the testicles produce sperm and testosterone.
Types and causes of hypogonadism
Primary hypogonadism is caused by a problem in the testicles. Secondary hypogonadism is caused by a problem in glands that tell the testicles to make testosterone.
Common causes of hypogonadism
|Primary (testicular)||Secondary (pituitary)|
|Abnormal development of the testicles due to genetic problems (Klinefelter syndrome)|
|* Decreased testosterone varies greatly among men. Almost a third of men older than age 75 have low testosterone.|
Hypogonadism can occur at any age. The symptoms will be different depending on your age when it develops. Common symptoms in adult men include:
- Hot flushes
- Low sex drive
- Erectile dysfunction
- Mood changes
- Difficulty concentrating
- Problems sleeping
- Loss of muscle mass
- Decreased bone density
- Enlarged breasts
- Loss of body hair
Older men with low hormone levels may have low sexual desire and activity, erectile dysfunction, and hot flushes. In men with normal testosterone levels, these symptoms can be caused by other conditions.
Hypogonadism can develop at any age but affects young children, adolescent boys, and men differently. It has little impact on young children and may well go away over time. In contrast, low hormone levels at puberty can affect a boy’s sexual development.
Adolescent boys with hypogonadism typically have undeveloped muscles and genitals, a high-pitched voice, and little or no body hair. Breasts may form, and arms and legs may become out of proportion to a small torso as they continue to grow.
In most cases, a delay in development is normal and will correct itself, although the wait may be emotionally and socially difficult.
Check for hypogonadism if a boy:
- Shows symptoms of hypogonadism
- Has male family members who had hypogonadism
- Has hormone levels that decrease, indicating Klinefelter syndrome
- Has had injuries, infections, or medical treatments that can affect hormone levels
Male hypogonadism is diagnosed based on:
- Long-term discomfort from symptoms
- Low testosterone levels in the blood measured at least two separate times
Your doctor might refer you to a hormone specialist (endocrinologist) if hypogonadism is suspected.
A physical exam will look at your body hair, muscle mass, and testicles. Your doctor will make sure they are consistent with your age. Your doctor will also take a medical history to assess your general health. Questions may include:
- When did your symptoms begin?
- Do they stop and start or happen all the time?
- Does anything make them better or worse?
- Have your testicles been injured in the past?
- Did you have undescended testicles as a child?
- When did you go through puberty?
For an adult patient, the doctor will also ask about your sexual life.
If you have symptoms of hypogonadism, your doctor will take blood to test your testosterone level. Blood should be drawn in the morning before breakfast. This test should be done at least two separate times.
If both tests confirm you have low testosterone, further testing can determine whether the cause is testicular (primary hypogonadism) or pituitary (secondary type).
Tests to determine type of hypogonadism
|Additional blood tests||Other conditions can cause the same symptoms as hypogonadism. Bloods tests will also assess levels of:|
|Imaging||MRI or CT scan may be used to check for tumours in the pituitary gland|
|Genetic testing||Some types of hypogonadism are caused by problems in the way the genes developed. These tests can check for genetic causes of low hormone levels.|
Losing weight, adjusting your diet, stopping smoking, and increasing exercise can improve your quality of life with hypogonadism. These changes can also help increase muscle strength and improve diabetes control and sexuality.
Hormone replacement therapy is the main treatment for both types of hypogonadism. Tumours found in the pituitary gland may require surgery, medication, radiation, or replacement of other hormones.
Hypogonadism and fertility
Hypogonadism can reduce sperm production and cause infertility. Men who want to have children should not use testosterone replacement, but other treatment may be available.
Men with hypogonadism caused by pituitary problems (secondary type) can potentially be treated with a hormone called human chorionic gonadotrophin, or hCG. This hormone stimulates production testosterone in the testicles. It is combined with treatment to increase production of sperm. This therapy can be used only for a limited time and should be guided by a competent specialist.
Men with hypogonadism caused by problems in the testicles (primary type) who have fertility problems need evaluation of the testicles and may require assisted reproductive technology. This technology can help couples who have not been able to conceive a child.
Regular medical monitoring is recommended during treatment. Your doctor will schedule visits with you to assess whether treatment is working, address possible side effects, and check treatment safety. Your testosterone will be tested over time to help determine the right dosage for therapy. Follow-up may include blood tests, examination of your prostate and your heart, and bone density scans.
With treatment, your symptoms will go away gradually. For example, your sex drive might improve first, then your mood might improve, and then erectile function might return.
For most adults with hypogonadism, the condition is lifelong and treatment is ongoing. The goal is to improve quality of life, sense of well-being, sexual function, and muscle and bone strength. Hormone replacement combined with weight loss, a healthy diet, stopping smoking, and increasing exercise can help.