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Can a shot a day (safely) keep aging away?

More and more Americans are turning to human growth hormones in an attempt to defy the effect of aging. But are they safe?

As baby boomers mature, their desire to defy and deny the effects of aging has led them to try some very expensive and cutting-edge measures. Over the past decade, a growing number of Americans have used human growth hormone. But, can a shot a day really — and safely — keep aging away?“Today” medical contributor Dr. Judith Reichman presents the latest information on this controversial area of medicine.

What is human growth hormone (HGH)?
HGH is a hormone that is produced in the pituitary gland of the brain.  Once released, it induces the liver to produce insulin-like growth factor 1 (IGF-1) and this hormone then triggers the growth of bones and body tissues. We know that the production of HGH is influenced by stress, sleep, exercise, food intake, and sugar levels. Growth hormone and IGF-1 levels peak during puberty, then gradually decline after the age of thirty.  But even though levels decrease, the normal pituitary never completely stops its production of HGH.

Most of our knowledge of HGH comes from studying individuals who lack these hormones.  In children HGH deficiency causes stunted growth and development.  In adults, significant deficiency may result from disease, tumors, surgery or radiation that destroys critical areas in the pituitary. This then leads to weight gain, lipid (cholesterol) abnormalities, coronary vascular disease, fatigue, decreased immune response, loss of muscle, and osteoporosis.  These individuals are also prone to depression and problems with sexual function.  When they are injected with corrective amounts of HGH, many of these problems resolve.

HGH declines with age. Does replacement prevent weight gain, loss of muscle and bone mass, and in general keep us in better shape and health?
The answer is that we're not sure. The types of studies we should be using to resolve this question are few, small and have rarely included women. Here are some of the more notable ones:

  • In 1990 a research report was published in the New England Journal of Medicine and became the Holy Grail for future anti-aging medication. The study included only twenty-one healthy men, ages sixty-one to eighty-one.  Twelve received injections of HGH for just six months, while nine served as controls. The results of this tiny study were proclaimed by many of the anti-aging clinics, web sites and dubious, quickly formed companies that sell products claiming to increase growth hormone as the legitimization of HGH therapy for all the woes of aging!.
  • In 1996 a double-blind study of HGH was published in the Annals of Internal Medicine.  Here 52 healthy men over age sixty-nine received HGH or a placebo for six months.  Those treated with HGH did not lose weight but their fat content decreased and muscle mass increased.  There was no corresponding increase in their muscle strength or intellectual skills and memories, nor did they feel happier.  However, compared with the placebo group they did have more frequent side effects such as swollen legs and pain in their joints that was severe enough for a quarter of them to have their dose reduced or stopped.
  • In 1998, Science carried a report on growth hormone research involving the Physicians Health Study.  Men who had naturally high levels of HGH were 4.3 times more likely to develop prostate cancer than men who had the lowest amounts.
  • In 2001, the Journal of Clinical Endocrinology and Metabolism published a six-month double-blind, placebo controlled trial of HGH. At last, this included forty-six healthy women, some taking hormone replacement therapy, as well as sixty-four men. The average age was 72. It was found that neither growth hormones nor hormone replacement therapy, nor both together, reduced abdominal fat in women, whereas HGH with or without testosterone did reduce abdominal fat by 7 to 16 percent in men. 
  • Finally, in 2002, another study published in the Journal of the American Medical Association examined the effect of six months of HGH with and without hormone replacement therapy (HRT) on fifty-seven women and seventy-four men age 65 to 88. The women treated with growth hormone averaged a 2.2 pound increase in their muscle mass, if they took HRT alone they did even better. HRT and HGH gave them a 4.5 pound benefit. But with or without these hormones, there was no significant improvement in their strength or cardiovascular endurance (as measured with a treadmill). The men seemed to have a greater response to HGH, showing marginal improvement in their strength and endurance. The most concerning aspect of this study was the high rate of side effects. Thirty-nine percent of women treated with HGH had swelling, 46 percent, joint pain, and 38 percent had carpal tunnel symptoms. Diabetes and glucose intolerance developed more often after HGH treatment in men than in women but occurred in both.

Overall, it would appear that men have a greater response to HGH than women, and do achieve marginal improvements in muscle mass, strength and endurance.

However, these studies show that this is probably no more than what they would have achieved by exercising three times per week for six months.

What about concerns that there is a connection between growth hormones and cancer?
The hormone induced by HGH, insulin growth factor-1, promotes the growth of cells and prevents them from dying, and that's exactly what cancer cells do: grow wildly and don't die. It's possible that this could happen if we raise HGH levels.  Once more, we're not sure whether this indeed occurs. A Nurses Health Study found that blood samples of HGH in three hundred and ninety-seven women who were diagnosed with breast cancer had higher levels of HGH more than ten years before the diagnosis of breast cancer when compared to the samples of six hundred and twenty women who had not developed breast cancer. They calculated that among women who developed breast cancer at a young age (before fifty), risk was increased four-fold by an elevated HGH but that there was no association with HGH levels in older, post-menopausal women. 

A 2002 article published in the journal Lancet reviewed the fates of over eighteen hundred English patients who received HGH in childhood or young adulthood. They found that they had a significantly increased risk of death from cancer, especially colorectal cancer and Hodgkin's disease. However, the type of HGH they received was not synthetic and doses were high. 

How is HGH made and why it is so expensive?
Human growth hormone is hard to synthesize. Its large and complex molecular structure involves a hundred and ninety-one amino acids.  Since 1985 growth hormone has been made through DNA technology; bacterial or animal cells are given a gene that directs them to make human growth hormones. The cells are then grown in a tissue culture which synthesizes a pure hormone identical to that produced by the human pituitary. We can't copy this substance using the growth hormones of animals or plants, and molecules of this size can't be absorbed through skin or mucous membranes. If taken in pill form it will be de-activated by stomach acid and enzymes, so it has to be given as a shot under the skin. Human growth hormone can only be manufactured by companies licensed by the Food and Drug Administration (FDA), prescribed and managed by a licensed physician, and administered via this type of injection. It is legal for physicians to prescribe this or any approved drug off label (for non-approved uses).

What is the FDA’s attitude toward HGH?
To date the FDA has approved the use of HGH only for children with inadequate growth hormone production or growth retarding diseases; in 2003, Humatrope (the most commonly used synthetic HGH) was also approved to treat healthy but extremely short children. Since 1996 HGH use has been officially extended to include adults who have growth hormone deficiencies due to pituitary or hypothalamic disease, surgery, injury or radiation therapy.  The prescribing information for Humatrope warns that its safety and effectiveness have not been evaluated in individuals over the age of sixty-five. 

Who administers the shots?
There's a small but growing group of physicians and scientists who are HGH believers. They have formed a professional association called the Academy of Anti-Aging Medicine, which now has nearly twelve thousand members world-wide. An estimated thirty thousand Americans were injecting growth hormones in 2001 at a cost of between twelve thousand and fifteen thousand dollars per person, per ear.

Dr. Reichman’s bottom line:Until we get more scientific information, I do not recommend that HGH be used for women who are healthy, but just getting older (and heavier). If you want to spend that kind of money, invest in better researched paths to better looks and longevity. Most important, exercise, eat properly and get the testing you need for early disease detection and treatment.

Dr. Judith Reichman, the “Today” show's medical contributor on women's health, has practiced obstetrics and gynecology for more than 20 years. You willl find many answers to your questions in her latest book, "Slow Your Clock Down: The Complete Guide to a Healthy, Younger You," published by William Morrow, a division of .

PLEASE NOTE: The information in this column should not be construed as providing specific medical advice, but rather to offer readers information to better understand their lives and health. It is not intended to provide an alternative to professional treatment or to replace the services of a physician.