Testosterone: What It Is and How It Affects Your Health

What Is Testosterone?

A hormone in both men and women


  1. Testosterone is a hormone found in men, and less-so in women.
  2. It’s most often associated with sex drive, but it also affects bone and muscle mass.
  3. Abnormally low or high levels can greatly impact a man's physical and mental health.

Testosterone is a hormone found in humans, as well as in other animals. The testicles primarily make testosterone in men. Women’s ovaries also make testosterone, though in much smaller amounts. Testosterone production starts to increase significantly during puberty, and begins to dip after age 30 or so.

Testosterone is most often associated with sex drive, and plays a vital role in sperm production. But it also affects bone and muscle mass, the way men store fat in the body, and even red blood cell production. A man’s testosterone levels can also affect his mood.

Low testosterone levels

Low levels of testosterone can produce a variety of symptoms in men, including:

  • decreased sex drive
  • less energy
  • weight gain
  • feelings of depression
  • moodiness
  • low self-esteem
  • less body hair
  • thinner bones

While testosterone production naturally tapers off as a man ages, other factors can cause hormone levels to drop. Injury to the testicles and cancer treatments such as chemotherapy or radiation can adversely affect testosterone production. Chronic diseases and stress can also reduce testosterone production. Some of these diseases include:

  • AIDS
  • kidney disease
  • alcoholism
  • cirrhosis of the liver

Testing testosterone

A simple blood test can determine testosterone levels. There is a wide range of “normal” or healthy level of testosterone circulating in the bloodstream. The normal range of testosterone for men is between 250 and 1100 ng/dL for adult males, and between 8 and 60 ng/dL for adult females, according to the Mayo Clinic. Ask your doctor to test your testosterone levels if you have concerns about low testosterone (low T).

Unusually low testosterone levels could be a sign of pituitary gland problems. The pituitary gland sends a signaling hormone to the testicles to produce more testosterone. A low T test result could indicate that the pituitary gland isn’t working properly. A young teen with low testosterone levels may simply be experiencing delayed puberty.

Moderately elevated testosterone levels in men tend to produce few noticeable symptoms. Boys with higher levels of testosterone may begin puberty earlier. Women with excessive testosterone may develop masculine features.

Abnormally high levels of testosterone could be the result of an adrenal gland disorder, or even cancer of the testes. High levels may also occur in less serious conditions. Congenital adrenal hyperplasia, which can affect males and females, is a rare but natural cause for elevated testosterone production. Your doctor may order other tests if your levels are exceedingly high.

Testosterone replacement therapy

Reduced testosterone production, a condition known as hypogonadism. This doesn’t always require treatment. A low T test result should trigger a check of your prostate health and red blood cell production. Serious medical issues sometimes coincide with decreased testosterone production, and should be diagnosed and treated if necessary.

You may be a candidate for testosterone replacement therapy if low T is interfering with your health and quality of life. Artificial testosterone can be administered orally, through injections, or with gels or patches on the skin. 

Replacement therapy may produce desired results, such as greater muscle mass and a stronger sex drive. However, the treatment does carry some side effects. Oily skin and fluid retention are common. The testicles may also shrink, and sperm production could decrease significantly. Some studies have found no greater risk of prostate cancer with testosterone replacement therapy, but it continues to be a topic of ongoing research.

Research shows little evidence of abnormal or unhealthy psychological changes in men receiving supervised testosterone therapy to treat their low T, according to a study in the journal Therapeutics and Clinical Risk Management. However, mental and physical risks are involved in self-administration of artificial testosterone. Anyone abusing synthetic testosterone, also known as anabolic steroids, may experience episodes of aggressive or violent behavior, along with physical side effects. Bodybuilders, athletes, or anyone who seeks to build muscle mass or achieve other benefits from artificial testosterone should be aware of these risks.

The takeaway

Testosterone is most commonly associated with sex drive in men. It also affects mental health, bone and muscle mass, fat storage, and red blood cell production. Abnormally low or high levels can affect a man’s mental and physical health. Your doctor can check your testosterone levels with a simple blood test. Testosterone therapy is available to treat men with low levels of testosterone. If you have low T, ask your doctor if this type of therapy might benefit you.    

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