Low Testosterone (Male Hypogonadism)

Low testosterone (male hypogonadism) is a condition in which your testicles don’t produce enough testosterone (the male sex hormone). Testicles are the gonads (sex organs) in people assigned male at birth (AMAB). More specifically, the Leydig cells in your testicles make testosterone.

Low testosterone causes different symptoms at different ages. Testosterone levels in adults AMAB naturally decline as they age. 

Other names for low testosterone and male hypogonadism include:

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• Testosterone deficiency syndrome.

• Testosterone deficiency.

• Primary hypogonadism.

• Secondary hypogonadism.

• Hypergonadotropic hypogonadism.

• Hypogonadotropic hypogonadism.

 

What does testosterone do?

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Testosterone is the main androgen. It stimulates the development of male characteristics and is essential for sperm production (spermatogenesis).

 

Your body usually tightly controls the levels of testosterone in your blood. Levels are typically highest in the morning and decline through the day.

Your hypothalamus and pituitary gland normally control the amount of testosterone your testicles produce and release.

Your hypothalamus releases gonadotropin-releasing hormone (GnRH), which triggers your pituitary gland to release luteinizing hormone (LH). LH then travels to your gonads (testicles or ovaries) and stimulates the production and release of testosterone. Your pituitary also releases follicle-stimulating hormone (FSH) to cause sperm production.

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Any issue with your testicles, hypothalamus or pituitary gland can cause low testosterone (male hypogonadism).

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Who does low testosterone (male hypogonadism) affect?

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Male hypogonadism is a medical condition that can affect people with testicles at any age from birth through adulthood.

Low testosterone is more likely to affect people who:

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• Are older.

• Have obesity.

• Have poorly managed Type 2 diabetes.

• Have obstructive sleep apnea.

• Have chronic medical conditions, such as kidney dysfunction or cirrhosis of the liver.

• Have HIV/AIDs.

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How common is low testosterone?

It’s difficult for researchers to estimate how common low testosterone is since different studies have different definitions for low testosterone.

Data suggest that about 2% of people AMAB may have low testosterone. And other studies have estimated that more than 8% of people AMAB aged 50 to 79 years have low testosterone.

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SYMPTOMS AND CAUSES

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What are the symptoms of low testosterone?

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

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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.

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Other symptoms of low testosterone in adults 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.