Low Testosterone (Male Hypogonadism)

Symptoms and Causes

What are the symptoms of low testosterone?

Symptoms of low testosterone can vary considerably, particularly by age.

Symptoms that highly suggest low testosterone in adults assigned male at birth include:

• Reduced sex drive.
• Erectile dysfunction.
• Loss of armpit and pubic hair.
• Shrinking testicles.
• Hot flashes.
• Low or zero sperm count (azoospermia), which causes male infertility.

Other symptoms of low testosterone in adults AMAB include:

• Depressed mood.
• Difficulties with concentration and memory.
• Increased body fat.
• Enlarged male breast tissue (gynecomastia).
• Decrease in muscle strength and mass.
• Decrease in endurance.

Symptoms of low testosterone in children

Low testosterone before or during puberty for children assigned male at birth can result in:

• Slowed growth in height, but their arms and legs may continue to grow out of proportion with the rest of their body.
• Reduced development of pubic hair.
• Reduced growth of their penis and testicles.
• Less voice deepening.
• Lower-than-normal strength and endurance.

What causes low testosterone?

There are several possible causes of low testosterone. The two types of male hypogonadism are:

• Primary hypogonadism (testicular disorder).
• Secondary hypogonadism (pituitary/hypothalamus dysfunction).

Causes of primary and secondary hypogonadism are also divided into either congenital (at birth) or acquired (developed later in childhood or adulthood).

Causes of primary male hypogonadism

Primary hypogonadism happens when something is wrong with your testicles that doesn’t allow them to make normal levels of testosterone.

Another name for primary hypogonadism is hypergonadotropic hypogonadism. In this type, your pituitary gland produces more luteinizing hormone (LH) and follicle-stimulating hormone (FSH) (known as gonadotropins) in response to low testosterone levels. The high levels of these hormones would normally tell your testicles to produce more testosterone and sperm. However, if you have damaged (most commonly related to prior chemotherapy) or missing testicles, they can’t respond to the increased levels of gonadotropins. As a result, your testicles make too little or no testosterone and sperm.

Sometimes in primary hypogonadism testosterone levels are within the normal range and gonadotropins are high. Your specialist will help you understand if you need treatment, even with normal testosterone levels.

Congenital conditions that affect your testicles and can lead to primary hypogonadism include:

• Absence of testicles at birth (anorchia).
• Undescended testicles (cryptorchidism).
• Leydig cell hypoplasia (underdevelopment of Leydig cells in your testicles).
• Klinefelter’s syndrome (a genetic condition in which people AMAB are born with an extra X chromosome: XXY instead of XY).
• Noonan syndrome (a rare genetic condition that can cause delayed puberty, undescended testicles or infertility).
• Myotonic dystrophy (part of a group of inherited disorders called muscular dystrophies).

Acquired conditions that affect your testicles and can lead to primary hypogonadism include:

• Testicle injury or removal.
• Orchitis, which is inflammation of one or both testicles. This is most often the result of a bacterial infection, such as a sexually transmitted infection, but it can be due to viral infections, such as mumps.
• Chemotherapy or radiation therapy to your testicles.
• Certain types of tumors.
• Anabolic steroid use.

Causes of secondary male hypogonadism

Conditions that affect how your hypothalamus and/or pituitary gland cause secondary hypogonadism. This is known as hypogonadotropic hypogonadism because there are low levels of luteinizing hormone (LH) and follicle-stimulating hormone (FSH). Those low levels cause decreased testosterone and sperm production.

Congenital conditions that can lead to secondary hypogonadism include:

• Isolated hypogonadotropic hypogonadism (a condition that causes low levels of gonadotropin-releasing hormone from birth).
• Kallmann syndrome (a rare genetic condition that causes loss of the development of nerve cells in your hypothalamus that produce gonadotrophin-releasing hormone. It can also cause a lack of smell.).
• Prader-Willi syndrome (a rare genetic multisystem disorder than can cause hypothalamus dysfunction).

Acquired conditions that can lead to secondary hypogonadism include:

• Hypopituitarism (This condition may result from an adenoma, infiltrative disease, infection, injury, radiation therapy or surgery that affects your pituitary gland.).
• Hyperprolactinemia.
• Iron overload (hemochromatosis).
• Brain or head injury.
• Cushing’s syndrome.
• Cirrhosis of the liver.
• Kidney failure.
• HIV/AIDS.
• Alcohol use disorder.
• Poorly managed diabetes.
• Obesity.
• Obstructive sleep apnea.
• Certain medications, including estrogens, psychoactive drugs, metoclopramide, opioids, leuprolide, goserelin, triptorelin and newer androgen biosynthesis inhibitors for prostate cancer.

Late-onset hypogonadism (LOH) is a type of secondary male hypogonadism that results from normal aging. As males age they have a deterioration of hypothalamic-pituitary function and Leydig cell function that decrease testosterone and/or sperm production.

LOH and low testosterone are more common in people AMAB who have Type 2 diabetes, overweight and/or obesity.

In one study, 30% of people AMAB who were overweight had low testosterone, compared to only 6% of those with weight in the normal range. In another study, 25% of people AMAB with Type 2 diabetes had low testosterone, compared to 13% of those without diabetes.