WebMD Medical News Archive
Human Growth Hormone and the Sex Hormones Estrogen and Testosterone
Since the days of Juan Ponce de Leon, mankind has been in a never-ending search for the Fountain of Youth. While there is still no magic tonic to reverse the aging process, a growing body of research suggests that substances called trophic factors, such as the human growth hormone and the sex hormones estrogen and testosterone, may be key ingredients.
That's good news, because the search has never been more urgent. Approximately 7 million elderly Americans now need long-term care to manage many activities of daily living, and the number will double by 2030 unless disability rates among older people decline, according to the U.S. Bipartisan Commission on Comprehensive Health Care.
Preliminary studies suggest that supplements of human growth hormone (GH), in particular, may reduce frailty, improve function, and maintain independence in older people.
Growth hormone is a protein produced by the pituitary gland. It triggers the release of an insulin-like growth factor that develops and maintains various tissues and organs.
Levels of testosterone in men and estrogen in women are known to decline with age, and some studies have shown that levels of GH also drop with age. There is some evidence -- but no proof -- that replacing both growth hormone and sex hormones in the body could help stave off some of the illnesses associated with advancing age.
Prompted by reports that extra GH increased lean body mass while decreasing body fat and the effects of aging among healthy men 65 and up who had low levels of GH, the National Institutes on Aging (NIA) in Bethesda, Md., awarded grants to eight researchers to study the hormone in 1992.
The studies are ongoing, and, to date, their results have been mixed. One study showed a 13% reduction in body fat among men taking GH, a 5.8% reduction among men taking only testosterone, and a 21% reduction in men taking both GH and testosterone. Other studies showed that people who took supplements of GH reduced their levels of low-density lipoprotein, or "bad" cholesterol.
Another study, however, showed that participants' triglycerides, or blood-fat levels, increased when they took GH. High levels of triglycerides are a risk factor for heart disease. Another consideration is that taking growth hormone and other hormones may cause sometimes-serious side effects, including carpal tunnel syndrome, worsening of diabetes, and fluid retention leading to congestive heart failure.
"While some of the changes associated with these hormone interventions appear to be in the direction commonly associated with younger, healthy individuals, the clinical usefulness of the interventions remains unclear," the NIA said in a statement.
"There is guarded optimism that some therapeutic maneuver that will raise growth hormone levels -- not necessarily giving growth hormone itself -- may have some value in preventing frailty and improving musculoskeletal function in older people," S. Mitchell Harman, MD, said in an interview on the topic last year. "But I think we have to say 'guarded optimism" at this point, because giving growth hormone per se doesn't seem to have the risk-benefit ratios that we're really looking for." Harman is with the NIA's Intramural Research Program and has been involved in many GH studies.
More optimistic is Joseph Raffaele, MD, co-founder of the Anti Aging Medicine Association of New York. Raffaele has been prescribing GH to patients for more than three years and says he has seen good results, including decreased fat mass without change in diet and exercise, increased lean muscle mass, stronger bones, improved heart and lung function, and reductions in blood pressure.
"Growth hormone is not the key to reversing the aging process because there is no single key. But it is certainly an important element of aging," he tells WebMD.
Vital Information:
• Approximately 7 million elderly Americans need long-term care, and that number is expected to double by 2030.
• Some scientific evidence shows that trophic factors, such as growth hormone, estrogen, and testosterone, may help combat the aging process.
• Growth hormone, in particular, may reduce frailty and help older people maintain independence, but studies are showing mixed results.
