Testosterone is a hormone produced by the testicles and is responsible for the proper development of male sexual characteristics. Testosterone is also important for maintaining muscle bulk, adequate levels of red blood cells, bone growth, sense of well-being and sexual function.
Inadequate production of testosterone is not a common cause of erectile dysfunction; however, when ED does occur due to decreased testosterone production, testosterone replacement therapy may improve the problem.
II. What causes testosterone deficiency?
As a man ages, the amount of testosterone in his body gradually declines. This natural decline starts after age 30 and continues throughout life. Other causes of lowered testosterone levels include:
- Injury or infection to the testicles
- Chemotherapy or radiation treatment for cancer
- Genetic abnormalities such as Klinefelter's Syndrome (extra X chromosome)
- Hemochromatosis (too much iron in the body)
- Dysfunction of the pituitary gland (a gland in the brain that produces many important hormones)
- Inflammatory diseases such as sarcoidosis (a condition that causes inflammation of the lungs)
- Medications, especially hormones used to treat prostate cancer and corticosteroid drugs
- Chronic illness
- Chronic kidney failure
- Liver cirrhosis
The significance of testosterone decline is controversial and poorly understood.
III. What are the symptoms of testosterone deficiency?
Without adequate testosterone a man may lose his sex drive, experience erectile dysfunction, feel depressed, have a decreased sense of well-being, and have difficulty concentrating.
IV. What changes occur in the body due to testosterone deficiency?
- Decrease in muscle mass, with an increase in body fat
- Changes in cholesterol levels
- Decrease in hemoglobin and possibly mild anemia
- Fragile bones (osteoporosis)
- Decrease in body hair
V. How do I find out if I have a testosterone deficiency?
The only accurate way to detect the condition is to have your doctor measure the amount of testosterone in your blood. Because testosterone levels fluctuate throughout the day, several measurements will need to be taken to detect a deficiency. Doctors prefer, if possible, to test levels early in the morning since this is when testosterone levels are at their highest.
VI. How is testosterone deficiency treated?
Testosterone deficiency can be treated by:
- Intramuscular injections, generally every two or three weeks
- Testosterone patch worn either on the body or on the scrotum (the sac that contains the testicles)
- Testosterone gel
- Mucoadhesive material applied above the teeth twice a day
Each of these options provides adequate levels of hormone replacement; however, they all have different advantages and disadvantages. Talk to your doctor to see which approach may be right for you.
VII. Who shouldn't take testosterone replacement therapy?
Men who have prostate cancer or breast cancer should not take testosterone replacement therapy. All men considering testosterone replacement therapy should undergo a thorough prostate cancer screening prior to starting this therapy.
VIII. What are the side effects of testosterone replacement therapy?
In general, hormone replacement therapy is safe. It is associated with some side effects, including:
- Acne or oily skin
- Mild fluid retention
- Stimulation of prostate tissue, with perhaps some increased urination symptoms such as a decreased stream or frequency
- Breast enlargement
- Worsening of sleep apnea (a sleep disorder that results in frequent night time awakenings and daytime sleepiness)
- Decreased testicular size
Laboratory abnormalities that can occur with hormone replacement include:
- Changes in cholesterol concentrations
- Increase in red blood cell count
- Decrease in sperm count, producing infertility (especially in younger men)
If you are taking hormone replacement therapy, regular follow-up appointments with your doctor are important.Like any other medication, directions for administering testosterone should be followed exactly as your doctor orders. If you are unsure or have any questions about testosterone replacement therapy, ask your doctor.
Reviewed by the doctors at the Glickman Urological Institute at The Cleveland Clinic.
Edited by Tracy Shuman, MD, November 2005, WebMD.
Copyright © 2004, The Cleveland Clinic.
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