It's a fact of life — as men age, the level of testosterone in their bodies decreases. But does this hormonal decline require treatment? The debate continues.
The possibilities are enticing — increase your muscle mass, sharpen your memory and mental focus, boost your libido, and improve your energy level. If you're an aging man, this may sound like the ultimate anti-aging formula. But such health benefits from testosterone therapy aren't quite so clear-cut.
"We just can't predict all the potential harmful effects of taking hormones even though on the surface they may seem beneficial."
Todd Nippoldt, M.D.
Mayo Clinic Rochester
Testosterone therapy has been used successfully for years to treat men with abnormally low testosterone levels — a medical condition called male hypogonadism. More recently, healthy, aging men have taken the hormone to boost waning testosterone levels. But not enough is known about the effects of testosterone therapy for this purpose. No long-term studies have weighed the potential benefits against the possible risks, including infertility and prostate problems.
Despite the lack of scientific evidence, testosterone therapy is growing in popularity. Pharmacies filled 2.4 million testosterone prescriptions in 2004 — more than twice the number filled in 2000, according to IMS Health, a company that tracks pharmaceutical sales. Though the number appears to be growing, there are no data that track who's filling these prescriptions — men or women — and for what purpose.
At the core of the controversy is whether gradually declining testosterone levels are a natural phenomenon or a health problem. And the practical question for men and their doctors is whether to treat it, particularly in the absence of scientific evidence. Before you buy into the tempting claims, find out what's known — and not known — about testosterone therapy so that you can make the best decision for you and your long-term health.
The natural decline of testosterone
Starting around age 40, a man's body produces less testosterone. Testosterone is the main male hormone that maintains muscle mass and strength, fat distribution, bone mass, sperm production, sex drive, and potency.
Many call this progressive decline of hormones "male menopause" or "andropause" and equate it to women's menopause. But this isn't a valid comparison, says Todd Nippoldt, M.D., an endocrinologist at Mayo Clinic, Rochester, Minn. "In women, ovulation ceases and female hormone production plummets over a relatively short time frame," says Dr. Nippoldt. "In men, there's a gradual decline in the production of male hormones."
For most men, testosterone levels naturally decline but still remain within the normal range throughout their lifetimes, causing no significant problems. But about two in 10 men age 60 and older have testosterone levels below the normal range (testosterone deficiency).
Testosterone deficiency can have several effects on the body, including:
§ Decreased energy
§ Reduced muscle mass and strength
§ Decreased cognitive function
§ Less sexual interest or potency
§ Depressed mood
If you experience these signs or symptoms, you may have testosterone deficiency. Other medical conditions — such as liver disease, hypothyroidism and depression — can cause these effects as can certain medications, including beta blockers, painkillers and certain drugs for depression or anxiety. In addition, some healthy men encounter these changes as a part of the aging process, possibly because of declining hormones other than testosterone.
Talk to your doctor if you're experiencing these signs and symptoms. He or she can help determine the likely cause and suggest the best treatment plan, if any.
Potential benefits and risks
In men with testosterone deficiency, testosterone therapy can restore sexual function and muscle strength, prevent bone loss and protect against heart disease (atherosclerosis). Also, some men taking testosterone therapy report an increase in energy, sex drive and well-being.
Some anti-aging enthusiasts claim that increasing the level of testosterone in older and healthy men provides these same benefits. Though potentially beneficial for some of these men, testosterone therapy isn't risk-free. High doses of testosterone may result in sleep apnea, infertility and excess blood production, which could increase the risk of stroke.
Increasing testosterone levels may also pose problems for the prostate, a small male gland that produces most of the fluids in semen. Testosterone naturally stimulates the growth of the prostate. Long-term testosterone treatment could cause prostate gland enlargement. Also, doctors are concerned that testosterone therapy might fuel the growth of prostate cancer that is already present. This is especially worrisome since prostate cancer is common in older men, and many men may have prostate cancer that is undiagnosed.
In addition, scientists have linked testosterone therapy to breast cancer in men. Breast cancer, like prostate cancer, is a hormone-dependent cancer. Because long-term testosterone treatment could cause breast enlargement in men (gynecomastia), doctors are concerned that testosterone therapy might also fuel the growth of breast cancer that is already present.
All men, especially those with a family history of prostate or breast cancer, should discuss the potential benefits and risks of testosterone therapy with their doctors before beginning treatment.
To carefully weigh the potential pros and cons for you, consider the following:
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Potential benefits
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Potential risks
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§ Improve muscle mass and strength
§ Increase bone mineral density
§ Thicken body hair and skin
§ Improve sexual desire
§ Boost energy
§ Decrease irritability and depression
§ Improve cognitive function
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§ Cause skin reactions
§ Cause fluid retention
§ Cause baldness
§ Cause or aggravate sleep apnea (brief, repeated cessation of breathing during sleep)
§ Stimulate noncancerous (benign) growth of the prostate and cause or worsen urinary symptoms
§ Stimulate growth of prostate cancer that's already present
§ Enlarge breasts (gynecomastia)
§ Stimulate growth of breast cancer that's already present
§ Cause testicle shrinkage (testicular atrophy)
§ Limit sperm production (infertility)
§ Stimulate excess blood production (polycythemia)
§ Cause acne
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Who should take testosterone therapy?
Testosterone therapy is clearly beneficial for men whose testicles fail to produce sufficient levels of testosterone (male hypogonadism). For this group of men, it can restore sexual function and muscle strength and prevent bone loss.
Few studies have evaluated possible benefits and risks of testosterone therapy for healthy aging men. And those that have been done provide conflicting results. Many questions remain unanswered, particularly the extent and the duration of the beneficial effects, which men might benefit, and the possible long-term risks.
In November 2003, the Institute of Medicine (IOM) reviewed the current evidence surrounding testosterone therapy and reported that this treatment is appropriate only for men who produce little or no testosterone. The IOM concluded that the long-term effects of supplemental testosterone on otherwise healthy men aren't known. And until more studies have been done, the institute recommends that testosterone therapy not be used to prevent or relieve the physical or psychological effects of aging.
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