A man looks out a window.

Testosterone is the primary sex hormone in men. It triggers the beginning of puberty in males. But it also has many other jobs in the human body.

What Does Testosterone Do?

Men need testosterone to make sperm and maintain their sex drive. The hormone also helps you keep muscle and bone strength as well as make red blood cells. It boosts your energy levels and contributes to your overall well-being.

Here are 10 facts every man should know about testosterone:

1. Testosterone Sets Off Puberty

Testosterone is the hormone responsible for changes in adolescence, such as:

  • Deepening of voice.
  • Growth of facial, pubic, and body hair.
  • Growth of penis and testicles.
  • Increased height.
  • Stronger muscles and bones.

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2. Testosterone Production Starts in the Brain

The pituitary gland, a small gland at the base of the brain, controls testosterone production. It sends signals to the testes to make testosterone. The hormone then circulates through the bloodstream to the entire body.

3. Testosterone Gives You Stronger Bones

Testosterone plays a role in bone density and maintaining bone health. As men age, bone density decreases. A healthy level of testosterone helps protect against bone diseases like osteoporosis.

4. Testosterone Affects Mental Health

Testosterone affects your thinking ability, mood, and memory. Men with low levels of testosterone may suffer from depression, fatigue, and general irritability.

5. Low Testosterone Has Wide-Ranging Consequences

If your body doesn’t make enough testosterone, you may experience:

  • A drop in your libido (sex drive).
  • Decreased bone mass.
  • Decreased muscle mass.
  • Enlarged or tender breasts.
  • Erectile dysfunction.
  • Low energy.
  • Low sperm count.

6. High Testosterone is Rare

It’s unusual for men to have naturally occurring high testosterone levels. If a man’s body is producing high levels of testosterone, it may be a sign of adrenal gland disease or testicular cancer.

Doctors sometimes also see high testosterone levels in men who are taking steroids to increase muscle mass.

7. Testosterone Levels Change From Morning to Afternoon

Hormone levels differ dramatically throughout the day. Testosterone levels tend to be highest in the morning, lowest in the evening. For that reason, doctors order testosterone bloodwork between 7 and 10 a.m.

8. You May be Able to Boost Your Testosterone Levels Naturally

There are many over-the-counter products that claim to give your testosterone a boost. But a healthy lifestyle is the best way to maintain normal testosterone levels. Support healthy testosterone levels by:

  • Avoiding high-fat, high-calorie processed foods.
  • Developing good sleep habits.
  • Eating lean protein, fresh fruits and vegetables, and fiber-rich whole grains.
  • Getting 30 minutes of exercise at least 5 times each week.
  • Limiting alcohol.
  • Not smoking.

9. Testosterone Levels Diminish Throughout a Man’s Life

The amount of testosterone in the bloodstream peaks in a man’s twenties. By age 30 or 35, testosterone levels decrease by about 1% each year. According to the Urology Care Foundation, about 50% of men over 80 have low testosterone.

This gradual drop is a normal part of aging. Lower testosterone in younger men has other causes, such as:

  • Alcoholism
  • Being overweight
  • Chemotherapy
  • Diabetes
  • Hormone disorders
  • Kidney disease

10. Testosterone Hormone Therapy Helps Some Men

Doctors sometimes prescribe testosterone therapy (TT) for men with low levels of the hormone. You may also need TT if your testicles get injured or are surgically removed (i.e. from cancer). Your doctor may give you TT in the form of gels, creams, skin patches, pills, or injection.

Doctors don’t always recommend TT if you have a normal age-related drop in testosterone. The risks may outweigh the benefits.

Side effects of testosterone therapy can include:

  • Accelerated growth of existing prostate cancer.
  • Acne.
  • Enlarged breast size.
  • Growth of benign prostatic hyperplasia.
  • Heart problems.
  • Reduced sperm production.
  • Sleep apnea.
  • Testicle shrinkage.

News-medical.net, What is Testosterone? Link

Urology Care Foundation, What Is Low Testosterone? Link

Harvard Health Publishing, Testosterone — What It Does and Doesn't Do, Link

National Institutes of Health, Understanding How Testosterone Affects Men, Link

Hormone Health Network, Testosterone and Androgens, Link

Hormone Health Network, What Does Testosterone Do? Link

U.S. National Library of Medicine, Testosterone Levels Test, Link

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