Low testosterone (male hypogonadism) is a condition in which the testes (the male reproductive glands) do not produce enough testosterone (male sex hormone).

In men, testosterone helps maintain and develop:

  • Sexual features
  • Muscle mass
  • Adequate levels of red blood cells
  • Bone density
  • Sense of well-being
  • Sexual and reproductive function

What causes low testosterone?

The amount of testosterone in a man’s body gradually drops as he age. This natural decline starts after age 30 and continues throughout his life

Other potential causes of low testosterone include the following;
1. Injury (trauma, interrupted blood supply to the testes) or infection of the testes (orchitis)

2. Chemotherapy for cancer

3. Metabolic disorders such as hemochromatosis (too much iron in the body)

4. Dysfunction or tumors of the pituitary gland

5. Medications, including opioids, hormones used to treat prostate cancer, and steroids (such as prednisone)

6. Acute (short-term) or chronic (long-term) illness

7. Alcohol abuse

8. Cirrhosis of the liver

9. Chronic renal (kidney) failure


11. Inflammatory conditions such as sarcoidosis (a condition that causes inflammation of the lungs and other organs)

12. Kallman syndrome (abnormal development of the hypothalamus)

13. Klinefelter syndrome (a genetic condition in which a male is born with an extra copy of the X chromosome).

14. High levels of the milk-producing hormone, prolactin

15. Obesity or extreme weight loss

16. Uncontrolled type 2 diabetes mellitus

17. Congenital defect (present at birth)

18. Obstructive sleep apnea

19. Aging

20. Estrogen excess (usually from an external or environmental source)

21. Severe primary hypothyroidism

22. Pubertal delay

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23. Trauma (head injury)

24. Radiation exposure or prior surgery of the brain


Hypogonadism usually is treated with testosterone replacement to return testosterone levels to normal.

Testosteronecan help counter the signs and symptoms of hypogonadism, such as decreased sexual desire, decreased energy, decreased facial and body hair, and loss of muscle mass and bone density.

For older men who have low testosterone and signs and symptoms of hypogonadism due to aging, the benefits of testosterone replacement are less clear.

While taking testosterone, it is important that your doctor monitor you for treatment effectiveness and side effects several times during your first year of treatment and yearly after that.