(LifeWire) - The sex hormone testosterone has been promoted by some practitioners as a kind of antiaging, cure-all treatment -- for men and women -- that can increase sex drive, lean muscle mass, energy levels and mental acuity. But how effective is testosterone therapy at achieving these benefits, and what are the long-term risks?
Though medical experts continue to research testosterone therapy, the answers to these questions remain largely unknown.
Testosterone's Functions and Fluctuations
Testosterone is responsible for some important bodily processes: producing red blood cells, distributing fat, increasing muscle mass and strength, producing sperm, and regulating sex drive and bone density. Though it is found in larger quantities in men's bodies, where it is produced primarily by the testes, women also produce small quantities in their ovaries and adrenal glands.
Testosterone levels typically peak in your teens and early twenties; in your thirties or forties, they usually begin a steady decline. The drop-off in middle-aged men has sometimes been referred to as "andropause," although many doctors doubt that this is a real or serious phenomenon.
Testosterone levels can also drop because of:
- Infection or injury to the testicles
- Medications, such as those treating prostate cancer
- Kidney or liver disease
- Cancer treatments, including chemotherapy and radiation
- Drug and alcohol abuse
Testosterone levels are determined by a blood test, although levels of the hormone fluctuate throughout the day and from day to day. Your doctor will probably require more than one test, usually performed early in the morning when testosterone levels are typically at their highest.
Available as a synthetic hormone, testosterone is approved by the FDA for the treatment of low levels of testosterone (hypogonadism). The drug is given as an injection, a patch, a gel or an adhesive material applied directly to the gums.
Low levels of testosterone have been blamed for several conditions, including depression, mood changes, low sex drive, loss of bone density, decreases in muscle mass and strength, increases in body fat, memory loss and lack of concentration. There isn't always a clear cause-and-effect relationship between these conditions and low testosterone levels.
Risks of Testosterone Therapy
Relatively few large studies have been done to determine the benefits or safety of long-term testosterone therapy. Like any drug, it has risks, including:
- Sleep apnea
- Oily skin and acne
- Mood changes
- Enlarged breasts (gynecomastia)
- Testicular shrinkage
- Decreased sperm production
- Frequent or persistent erections
- Excess red blood cell production (potentially adding to stroke risk)
Testosterone therapy has also been implicated in an increased risk of breast and prostate cancer, although more research must be done to determine the strength of the association.
The Institute of Medicine (part of the National Institutes of Health) conducted a study to assess the risks and benefits of testosterone therapy. In 2003, it concluded that until the effectiveness and safety of testosterone can be proven, it's best to limit its use to men with low testosterone levels.
According to the NIH, ". . . although some older men who have tried these treatments report feeling 'more energetic' or 'younger,' testosterone therapy remains a scientifically unproven method for preventing or relieving any physical or psychological changes that men with normal testosterone levels may experience as they get older."
Read more on Testosterone and Aging:
- Testosterone, Men and Sex
- Can Testosterone Slow Aging?
- Is Testosterone Overrated
- Other Popular Anti-Aging Hormones
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"NIA Statement on IOM Testosterone Report." nih.gov. 12 Nov. 2003. National Institutes of Health. 1 Mar. 2009 <http://www.nih.gov/news/pr/nov2003/nia-12.htm>.
"Testosterone Therapy May Benefit Post-Menopausal Women." ynhh.org. 3 Nov. 2000. Yale-New Haven Hospital. 1 Mar. 2009 <http://www.ynhh.org/healthlink/womens/womens_11_00.html>.
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