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Growth Hormones & Longevity

Jun 14, 2011 | By Tricia McMillan

Human Growth Hormone has been touted as the "fountain of youth," with supplements aggressively marketed to bodybuilders who fear losing muscle mass as they age. Questions have arisen as to whether HGH actually affects the life span, as opposed to just reducing the physical symptoms of aging, and the results of research have thus far been inconclusive.

Growth Hormone Lengthens Life

A 2003 study in the "Journal of Clinical Endocrinology and Metabolism" found that patients with untreated growth hormone deficiencies died at significantly younger ages than their siblings without the disorder because they are at a higher risk of cardiovascular disease. This does not necessarily mean that growth hormones lower the risk, however. It is possible that the genetic situation that caused the hormone deficiency contributes to the cardiovascular risk, rather than the deficiency itself.

Growth Hormone Shortens Life

A 2001 study in the "Proceedings of the National Academy of Science of the Unites States of America" found that mice with a particular mutation that decreases natural growth hormone production had a longer life, with age-related collagen and immune system changes setting in at more advanced ages than mice without the mutation. Similarly, a 2010 study in the journal of the Federation on American Societies for Experimental Biology showed that mice with underactive pituitary glands that were injected with growth hormones at a young age lived shorter lives with a lower level of cellular resistance to toxins than mice not exposed to extra growth hormones.

Growth Hormone Has No Effect on Longevity

As if it weren't enough to have research demonstrating that growth hormones both do and don't extend longevity, there is also research that claims it has no effect at all upon lifespan. In an effort to reconcile the conflicting research on the subject, Dr. Roberto Salvatori of Johns Hopkins University led a study involving a population of dwarves in a remote area of Brazil. The test subjects all had a particular genetic mutation that caused a severe growth hormone deficiency. He found that the hormone-deficient dwarves lived lives just as long as their unaffected siblings, and once the analysis was adjusted to mirror the general population, the dwarves' lifespans were exactly the same as everyone else. Dr. Salvatori and his team concluded in January 2010 that growth hormone levels don't affect the lifespan either way.

Possible Contributing Factors

There are many reasons why research results may vary to such a degree. One difference is the difference in physiology between mice and humans -- the study from the "Journal of Endocrinology and Metabolism" demonstrates that. Another difference is the exact nature of the disorder that causes the patient to have a hormone deficiency in the first place -- it could be that the genetic mutation affects the lifespan, not the hormone itself. There have been studies that point out that other factors may also come into play -- A 2009 study in the "Journals of Gerontology Series Biological Sciences and Medical Sciences" states that growth hormones administered to pituitary-deficient mice may increase insulin sensitivity and reduce insulin levels, thus extending the lifespan The study authors also note that the insulin response to the hormone may stop once the hormone supplementation is taken away.

A 2002 study in the American Journal of Pathology posits that the level of growth hormone must be just right -- too much can promote aging and shorten the lifespan, but a reduction in a particular growth hormone as opposed to others may lengthen life.

References

Article reviewed by GlennK Last updated on: Jun 14, 2011

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