Testosterone is the chief male sex hormone, and plays an important role in men’s overall well-being and health. “Produced in the testicles, it travels to the centres in the brain responsible for mood, cognition and libido,” says Dr. Jerald Bain, an endocrinologist at Mount Sinai Hospital in Toronto. “It also stimulates red blood cell formation and helps maintain bone strength.”
But when the body doesn’t make enough, men can experience poor concentration, decreased motivation, lethargy and a low sex drive. The testes themselves need testosterone for normal sperm production. Bain estimates that up to 50 percent of men over age 50 have low- or below-normal bioavailable testosterone levels. Lack of treatment could lead to osteoporosis and erectile dysfunction, and a recent study found that men with low testosterone may even die earlier.
What's normal?
Testosterone levels do drop gradually as men grow older—one study showed a decline of 1.2 percent per year after age 25. “Probably a significant number of Canadian men are symptomatic due to reduced testosterone availablilty and are not being diagnosed or treated,” says Bain. A simple blood test can determine if your man is manufacturing enough. Bain says the normal range varies depending on the test laboratory, but in general, anything below eight to 10 nanomoles per litre is deficient.
Some potential causes
Low testosterone may result from a problem within the testes (due to aging, infection or inflammation caused by viruses), or from reduced secretion of luteinizing hormone. Created by the pituitary gland, it triggers the release of testosterone in pulses at 90-minute intervals. “When this pulsing pattern stops, testosterone falls and causes symptoms,” says Dr. Richard Spark, director of the Steroid Research Lab at Beth Israel Deaconess Medical Center in Boston and an associate clinical professor of medicine at Harvard Medical School. Nobody knows why the pulses stop in some men and not in others.
Bain says new research links low testosterone with obesity, diabetes, high blood pressure, high cholesterol and coronary artery disease. Chromosomal abnormalities or tumours on the pituitary gland can also play a role, as can testicular cancer. Since this cancer occurs more frequently in young men, they should do regular self-exams (look for a hard mass or nodule within the testes), and make sure a doctor also examines the area during annual checkups.
Treatment options
To restore testosterone levels, an endocrinologist can provide it in several forms: injection, daily pills or topical patches and gels. (None are similar to drugs such as Viagra that only treat erectile dysfunction.) “The gold standard is injection into the buttocks every two weeks,” says Bain. The other formats need to be absorbed into the body, and people absorb them at different rates. But be patient. Though results are detectable immediately in the blood, Spark says it can take a month or more to notice a real difference. “By then, my patients tell me their mood has improved, along with their strength and libido.”
This article was originally titled "No energy?" in the October 2009 issue of Best Health. Subscribe today to get the full Best Health experience—and never miss an issue!—and make sure to check out what's new in the latest issue of Best Health.
