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The Facts About Low Testosterone

Find out how low-T affects your sexual health.

A close up of a man looking concerned while holding his head against his hand.

Testosterone levels begin to naturally and gradually decline as men age. However, low-T is a condition that can affect men of any age and cause complications in physical, mental and sexual health.

What is testosterone?

Testosterone is a naturally occurring sex hormone in the body. In men, testosterone is produced in the testicles. The body also transforms dehydroepiandrosterone (DHEA), a hormone made by the adrenal glands, into testosterone.

Androgens are a group of hormones that influence male traits. As the main androgen, testosterone plays a key role in male physiology. It is responsible for several aspects of male development, including:

  • Muscle development
  • Strength
  • Increase in height
  • Bone mass
  • A deep voice
  • Facial and pubic hair
  • Genitalia growth
  • Fertility
  • Sex drive
  • Sperm and semen production 

Women have testosterone, too, but it is naturally much higher in men.

Facts, stats and history

It's difficult to determine exactly how many men have low-T. The available data suggests that about 2.1 percent of men have the condition, but the rate varies by age. About 8 percent of men ages 50 to 79 have low-T, while the percentage is about 1 percent for young men.

Testosterone was discovered and named in 1935. Even before it had a name, though, philosophers such as Aristotle and other thinkers and practitioners of early medicine theorized about such a substance, noticing that castration had significant impacts on fertility and sexual function. This shows that even thousands of years ago, people understood the testicles had some connection to reproductive and sexual health.

With the development of modern medicine, experts have learned much more about the sex hormone produced in the testes and the vital role it plays in the physical, mental and sexual health of men.

Causes of low testosterone

Low-T occurs when the testicles begin making a less-than-normal amount of testosterone, which results in an overall dip in testosterone levels in the blood. Low-T can be caused by several different factors.

For example, low-T has been linked to:

  • Obesity
  • Aging
  • Use of some antidepressants and narcotic pain medications
  • Metabolic syndrome

Men with HIV and AIDS are at a greater risk for low-T, according to the Urology Care Foundation. Individuals may have low-T as a result of other existing conditions, such as Klinefelter syndrome, Noonan syndrome and ambiguous genitalia, a condition that occurs when a person is born with sex organs that develop atypically.

Low-T may develop as a result of certain circumstances, including the following:

  • Testicle damage sustained by accident
  • Testicle removal due to cancer
  • Autoimmune disease
  • History of chemotherapy or radiation therapy
  • Infection
  • Hormone deficiency caused by pituitary gland disease

Signs and symptoms of low-T

You may have low-T if you experience any of the following signs and symptoms:

  • Loss of lean muscle mass
  • Diminished sex drive
  • Loss of body hair
  • Fatigue
  • Erectile dysfunction (ED)
  • Lack of semen production
  • Obesity
  • Depression
  • Memory and concentration problems

When to call the doctor

If you are experiencing any persistent or worrisome symptoms, consult your doctor, who can rule out other potential causes and determine whether you have low-T.

If low-T is the cause of your symptoms, several treatment options are available. Early detection in boys is essential to prevent complications caused by delayed puberty and reduce their risk for osteoporosis and other similar conditions.

Diagnosis and testing

If you are exhibiting signs and symptoms of low-T, your doctor may order a blood test to determine if your blood testosterone levels are normal.

Testosterone levels in the blood are measured in nanograms per deciliter (ng/dL). The American Urological Association considers testosterone levels below 300 ng/dL to be low-T. Boys ages 17 and 18 normally have testosterone levels that range anywhere from 300 to 1,000 ng/dL. This range decreases to 240 to 950 ng/dL in men 19 and older.

Once you receive a low-T diagnosis, your doctor may conduct further testing to determine whether the condition is caused by a testicular disorder or a pituitary abnormality. These tests may include semen analysis, genetic studies, pituitary imaging, hormone testing and testicular biopsy.

Let your doctor know about any medications you're using or other health conditions you have as these could be contributing to the low-T and your doctor can determine that possibility.


Depending on the cause of your low-T, you may benefit from enacting a few natural strategies that improve your overall health and give you a boost in testosterone levels.

Natural low-T treatments include the following:

  • Eating a healthy, well-balanced diet
  • Exercising regularly
  • Maintaining a healthy weight
  • Improving your sleep habits

If natural remedies alone don't work, there are other treatments available that can help mitigate the symptoms of low-T. The most common low-T treatment is testosterone replacement therapy (TRT).

Testosterone replacement therapy can be administered in the following ways:

  • Testosterone patches applied to different parts of the body daily
  • Intramuscular injections administered regularly on a 10- to 14-day cycle
  • Testosterone gel applied to the arms and back daily
  • Pellets implanted beneath the skin periodically every few months

If you are considering TRT, be sure to talk to your doctor about the risks and benefits of the treatment. Side effects may include acne, prostate enlargement, breast enlargement, sleep apnea, testicle shrinkage, infertility and more.

Your doctor may also recommend treating underlying conditions that could be contributing to low-T, such as diabetes, alcohol use disorder, sleep apnea, obesity, HIV and anemia.

Prevention and aftercare

There is no surefire way to prevent low-T. You can, however, take a few measures to decrease your risk of developing the condition. These include eating a healthy and balanced diet, exercising regularly, maintaining a healthy weight and keeping healthy sleep habits.

If you do develop low-T and undergo treatment, be sure to talk to your doctor about any side effects you may experience. Many symptoms may be mitigated with additional medication or other measures.

Clinical trials and research

Clinical trials are critical to the advancement of medical research. These trials are often used as tools to research cures, treatments and methods of prevention for diseases and conditions such as low-T. Before participating in any clinical trial, it's important to first conduct plenty of research, consult your doctor and take time to consider what's best for you. A list of active and recruiting clinical trials is available at


What does low-T do to a man?

Having low-T can lead to an array of symptoms, including loss of muscle mass, lowered sex drive, loss of body hair, fatigue, erectile dysfunction, lack of semen production, obesity, depression, and memory and concentration problems. In boys, low-T can delay puberty.

What does it mean when your T levels are low?

Having low-T means the level of testosterone in your blood is lower than normal. Testosterone levels in the blood are measured in nanograms per deciliter (ng/dL). Normal testosterone levels for boys ages 17 and 18 range from 300 to 1,000 ng/dL. This range decreases to 240 to 950 ng/dL in men 19 and older. The American Urological Association considers any testosterone levels below 300 ng/dL as low-T.

What are the symptoms of low-T in men?

Low-T can leave a man feeling fatigued and depressed. It can cause physical changes such as loss of body hair and muscle mass. Sexual function can be impacted, as low-T can lead to erectile dysfunction and lack of semen production. For some men, low-T can impact memory and lead to concentration problems.