International Health News

GH Enhancers: Are They Worth the Risk?

by Hans R. Larsen, MSc ChE

Hans LarsenGrowth hormone (GH) enhancers are getting a great deal of attention these days especially among bodybuilders. An 8-week course of GH enhancer is reputed to produce 15 or more pounds of solid muscle when combined with regular weight training(1). Human growth hormone is necessary for growth and a deficiency produces short people. GH does not actually stimulate growth directly, but causes the release of insulin-like growth factors, particularly insulin-like growth factor 1 or IGF-1. It is IGF-1 that is responsible for growth and it stimulates the synthesis of lean muscle mass in particular. Human IGF-1 levels vary with age; they are particularly high during puberty and by the age of 60 years they are only about half the average value (200 micrograms/liter) of a younger adult(2,3).

Experiments to increase IGF-1 levels in older men through injections of recombinant (synthetic) GH produced astounding results. An 8.8% increase in lean body mass, a 14.4% decrease in fatty tissue, a 1.6% increase in vertebral bone density, and a 7.1% increase in skin thickness were reported by American medical researchers in 1990. Their trial lasted a year and although the 21 participants all remained healthy except for one who developed prostate cancer, the researchers warned that side effects such as edema, hypertension, diabetes, and enlargement of the heart could occur with prolonged use of synthetic GH. Other researchers found that GH injections in young people produced larger muscles and kidneys. More recently GH injections have become popular among athletes as a super- efficient way to increase muscle mass and strength(1,4).

Growth hormone is naturally secreted by cells in the pituitary gland and acts on the liver to produce IGF- 1. IGF-1 levels are normally quite steady, but increase during periods of excessive stress, through exercise, and by consuming a diet rich in certain amino acids especially arginine, ornithine, glycine, and lysine. These amino acids act directly on the pituitary gland to stimulate the production of GH and its downstream fellow hormone, IGF-1. So why not just eat a lot of these amino acids if you want to grow bigger muscles? Unfortunately, or perhaps fortunately as we shall see later, stomach acid is very tough on amino acids and only 10% or less of them actually survive long enough to get into the blood stream. This is where GH enhancers play a role. These products use a patented process to protect the amino acids in the stomach and as a result 90% or more of them are absorbed into the blood stream. It is claimed that the resulting flooding of the pituitary gland with the raw materials it needs to produce growth hormone can result in IGF-1 level increases of 200% or more. Surprise, surprise! The body has a built- in mechanism to prevent IGF-1 levels from going too high. Somatostatin is released by the hypothalamus and its major role is to keep IGF-1 levels under control. Another challenge for supplement purveyors? Not really since GH enhancers also contain special peptides which suppress the natural release of somatostatin(1-3).

My favourite Supplements

Now, why would the body go out of its way to prevent high IGF-1 levels when they result in rippling muscles, sculpted bodies, and virtual 10 to 20 year age reversal in older men? Why indeed? The answer is simple, excessive IGF-1 levels can make you very, very sick and yes, they can actually kill you! High IGF-1 levels in children who are not yet fully grown cause gigantism and excessive levels in adults are associated with acromegaly. Acromegaly is not a fun thing with such manifestations as fatigue, coarse facial features, headaches, decreased vision, congestive heart failure, kidney stones, joint pains, and of particular interest to young men, impotence and a lack of sexual desire. It is said that acromegalics look more like each other than like their own family members. As a matter of fact, some pictures of bodybuilders on GH enhancers look suspiciously like the classic depictions of acromegalics. Acromegalics also have higher incidence of cancer especially colon cancer and pituitary tumors(2,5).

OK you may say, I can live with this as long as I have the largest muscles on the block. But can you also live with prostate, lung, and colon cancer? Researchers at the National Institutes of Health reported a connection between cancer risk and high IGF-1 levels in 1995. In 1998 researchers at the Harvard School of Public Health reported that a high IGF-1 level is the single most important risk factor for prostate cancer and that high IGF-1 levels were present many years before the cancer was actually diagnosed. Other researchers have found that high IGF-1 levels combined with high testosterone levels are a potent risk. High IGF-1 levels have also been implicated as strong risk factors in breast and colon cancers and now lung cancer is about to be officially added to this list. Recent research has shown that artificially increasing IGF-1 levels in mice accelerates the growth of cancerous tumors(5-10).

Dr. Samuel Epstein, MD, a professor at the University of Illinois School of Public Health says that "Taking supplements to increase your IGF-1 levels is reckless, extreme, and bordering on the criminal". Dr. Derek LeRoith of the National Institutes of Health agrees and says that there is now enough evidence that taking GH supplements when you are not deficient will increase the risk of cancer and acromegaly. Says Dr. LeRoith "If you ask me if I would take them, the answer is a definite no". Dr. Michael Pollak, a member of the Harvard team who reported the prostate cancer connection also condemns the use of GH enhancers by normal, healthy individuals. Dr. Pollak points out that growth hormone supplementation has a definite place in medicine in cases where people are deficient and need to increase their IGF-1 levels from sub-normal to normal. However, people who have normal levels would run a significantly increased risk of acromegaly and prostate cancer if they were to take GH enhancers on a sustained basis. Dr. Pollak is also concerned about giving IGF-1 to older people with normal levels for their age. He says the benefits are uncertain and the risks unknown.(5,11-13).

A distinguished group of researchers at the University of Bristol in the UK recently voiced their concern about the increasing use of IGF-1 and growth hormone enhancers by bodybuilders and elderly people trying to recapture their youth. Says Dr. George Davey Smith "People using growth hormone and IGF-1 enhancers are unlikely to be aware of their potentially harmful effects".(14)

  1. Ironman, November 1998, pp. 54-6, 192
  2. Harrison's Principles of Internal Medicine, 12th edition, McGraw-Hill, NY, 1991, pp. 1660-82
  3. Williams Textbook of Endocrinology, 8th edition, W.B. Saunders Company, 1992, pp. 175-77 and 1096-1106
  4. Rudman, Daniel, et al. Effects of human growth hormone in men over 60 years old. New England Journal of Medicine, Vol. 323, July 5, 1990, pp. 1-6
  5. Conversation with Dr. Derek LeRoith on October 1, 1998
  6. LeRoith, D., et al. The role of the insulin-like growth factor-I receptor in cancer. Annals of the New York Academy of Sciences, Vol. 766, September 7, 1995, pp. 402-08
  7. Chan, June M., et al. Plasma insulin-like growth factor-I and prostate cancer risk: a prospective study. Science, Vol. 279, January 23, 1998, pp. 563-66
  8. Mantzoros, C.S., et al. Insulin-like growth factor 1 in relation to prostate cancer and benign prostatic hyperplasia. British Journal of Cancer, Vol. 76, No. 9, 1997, pp. 1115-18
  9. Hankinson, Susan E., et al. Circulating concentrations of insulin-like growth factor-I and risk of breast cancer. The Lancet, Vol. 351, May 9, 1998, pp. 1393-96
  10. Butler, A.A., et al. Stimulation of tumor growth by recombinant human insulin-like growth factor-I (IGF-I) is dependent on the dose and the level of IGF-I receptor expression. Cancer Research, Vol. 58, July 15, 1998, pp. 3021-27
  11. Conversation with Dr. Samuel Epstein on September 28, 1998
  12. Conversation with Dr. Michael Pollak on October 1, 1998
  13. Carter, W.J. Effect of anabolic hormones and insulin-like growth factor-I on muscle mass and strength in elderly persons. Clinics in Geriatric Medicine, Vol. 11, November 1995, pp. 735-48
  14. Smith, George Davey, et al. Cancer and insulin-like growth factor-1. British Medical Journal, Vol. 321, October 7, 2000, pp. 847-48 (editorial)
This article was first published in International Health News Issue 110, February 2001


Subscription to IHN

Donation appeal

My favourite Supplements

copyright notice