Low Testosterone Overview:
What is low testosterone (male hypogonadism)?
Low testosterone (male hypogonadism) is a condition in which the testicles do not produce enough testosterone (the 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
How common is low testosterone?
Low testosterone affects almost 40% of men over the age of 45.
What causes low testosterone?
As a man ages, the amount of testosterone produced in his body gradually drops. This natural decline starts after age 30 and continues at a rate of about 1% per year throughout his life.
There are many other potential causes of low testosterone including:
- Injury or infection of the testes
- Chemotherapy treatment
- Metabolic disorders such as hemochromatosis
- Dysfunction or tumors of the pituitary gland
- Medications such as opioids, hormones used to treat prostate cancer, and steroids
- Illness
- Alcohol abuse
- Cirrhosis of the liver
- Chronic kidney failure
- HIV/AIDS
- Inflammatory conditions such as sarcoidosis
- Kallman syndrome
- Klinefelter syndrome, also called XXY syndrome
- High levels of the milk-producing hormone prolactin
- Obesity or extreme weight loss
- Uncontrolled type 2 diabetes mellitus
- Congenital defect
- Obstructive sleep apnea
- Aging
- Estrogen excess
- Anabolic steroid abuse
- Severe primary hypothyroidism
- Pubertal delay
- Head Trauma
- Radiation exposure
What are the symptoms of low testosterone?
Symptoms of low testosterone depend on the age of the person but include:
- Low sex drive
- Erectile dysfunction
- Decreased sense of well-being
- Depressed mood
- Difficulties with concentration and memory
- Fatigue
- Moodiness and irritability
- Loss of muscular strength
Other changes that occur with low testosterone include:
- A decrease in hemoglobin and mild anemia
- A decrease in body hair
- Osteoporosis
- Increased body fat
- Breast development (gynecomastia)
- Infertility
Diagnosis and Tests:
How is low testosterone diagnosed?
Low testosterone is diagnosed with a blood test to measure the amount of testosterone in the blood. It may take several measurements to determine if a patient has low testosterone as levels normally fluctuate throughout the day. The highest levels of testosterone are generally in the morning, near 8 a.m.
Management and Treatment:
How is low testosterone treated?
Low testosterone is treated with testosterone replacement therapy, which can be performed via:
- Intramuscular injections every 10 to 14 days
- Testosterone patches that are applied daily to different parts of the body
- Testosterone gels that are applied daily to upper back and arms
- Pellets that are implanted under the skin every two months
NOTE: Oral testosterone is not currently approved for use in the United States.
What are the side effects of testosterone replacement therapy?
The side effects of testosterone replacement therapy include:
- Acne or oily skin
- Swelling in the ankles
- Stimulation of the prostate that can cause urination symptoms
- Breast enlargement or tenderness
- Worsening of sleep apnea
- Smaller testicles
- Skin irritation
Laboratory abnormalities that can occur with testosterone replacement include:
- Increase in prostate-specific antigen (PSA)
- Increase in red blood cell count
- A decrease in sperm count, producing infertility
If you are taking hormone replacement therapy, regular follow-up appointments with your physician are important.
Who shouldn’t undergo testosterone replacement therapy?
Testosterone replacement therapy may cause the prostate to grow. If a man has early prostate cancer, a concern is that testosterone may stimulate cancer growth. Therefore, it is important for all men considering testosterone replacement therapy to undergo prostate screening before starting treatment. Men who are found to have prostate cancer should not undergo testosterone replacement therapy.
Guidelines suggest physicians should assess for prostate cancer risk by performing:
- PSA tests at 3, 6, and 12 months within the first year after beginning therapy, and then every year after that
- A digital rectal examination of the prostate at 3-6 months and 1 year after beginning therapy, and then every year after that.
- Hematocrit levels will be checked before testosterone therapy starts, and then on a regular basis to make sure red blood cell levels remain normal.
NOTE: A digital rectal exam is recommended even for men who are not undergoing testosterone replacement therapy, as an age-related prostate cancer screening starting around age 50.
Other men who should not take testosterone replacement therapy include those who have:
- An enlarged prostate
- A lump on their prostate that has not been evaluated
- A PSA measurement above 4
- Breast cancer
- An elevated hematocrit level
- Severe congestive heart failure
- Obstructive sleep apnea that has not been treated
Prevention:
Can low testosterone be prevented?
There are no known ways to prevent low testosterone that is caused by genetic conditions or damage to the testes or pituitary gland.
A healthy lifestyle that includes good nutrition, exercise, weight management, and that avoids excessive use of alcohol and drugs can help keep testosterone levels normal.
References:
- The Endocrine Society: Testosterone Therapy in Men
- American Urological Association: What is Low Testosterone?