(2 of 2)
The researchers emphasize that their findings are preliminary and that it is far too early to consider HGH-replacement therapy for all senior citizens. One reason to be cautious is that overdoses of growth hormone can cause diabetes, arthritis, high blood pressure, heart failure and other side effects. Although none of the men in the Wisconsin study had these problems, long-term use of HGH might increase the risk. Other questions that remain to be answered include the age at which treatment should begin, what the optimal dose is, whether the changes will disappear if the therapy is discontinued and whether it is effective in older women. The high cost of HGH -- about $14,000 for a year's supply -- is a severe drawback.
Whatever its potential, HGH-replacement therapy is not a cure-all for aging. For one thing, cells of the brain, eyes, ears and elastic tissues such as ligaments and tendons are not responsive to HGH. "The ((Wisconsin)) study does demonstrate clear-cut effects of growth hormone," says Dr. Mary Lee Vance, a University of Virginia endocrinologist who wrote an editorial accompanying the report, "but to say it reverses the effects of aging is an overstatement. It's just one part of the equation." Other processes that may influence aging include cumulative tissue damage caused by destructive particles called free radicals that form within the body, and the inability of genetic material to repair itself completely after being harmed by everything from pollutants to cosmic rays.
While HGH cannot make time stand still, it may help stave off some of the worst effects of aging, including the muscle deterioration that leaves many older people unable to climb stairs or carry groceries. No one yet knows if the larger muscles that HGH stimulates in the elderly will function as younger muscles do. But if that turns out to be the case, at least some of the elderly could get a chance to be more active and productive in their final years.
CHART: NOT AVAILABLE
CREDIT: TIME Chart by Joe Lertola
CAPTION: EFFECTS OF HUMAN-GROWTH-HORMONE INJECTIONS IN MEN OVER 60