Scientists, researchers, and medical centers worldwide are aware of how growth hormone has the ability to curb the effects of aging. 
This idea alone is sufficient reason for many people to take steps to raise their natural HGH production.
However, if that’s all HGH did its notoriety would fade. While the ability to put the brakes on the aging process is certainly exciting it does not necessarily mean a longer life.
There are a multitude of ways that our body systems age. Some of those systems are infinitely more important to our health and resistance to disease. 
Researchers are asking some interesting questions about how HGH is related to immune function
Is heart disease a direct result of aging?  When hormones decline what is the resulting impact through the body’s systems? Why does age put a person into a higher risk category of brain related issues?
Why does a simple infection kill an older person but is barely noticed by a younger person? It appears that in each of the above questions HGH is a central figure.
Our immune system degrades with age
Put bluntly the immune system is the number one mechanism in our physiology that enables us to survive.
Each day our immune systems front line warriors the lymphocytes, phagocytes and killer cells are programmed to wage war against anything that could potentially compromise our health.
Without it, our time on the planet would be short lived.
It’s important to recognize it for what it is and what it does – it allows us to live in a very dangerous environment. Scientists have confirmed that with age our immune function drops. Once the decline begins to take place we are vulnerable to autoimmune challenges, cancer, viral and bacterial infection.
Question is – How do we go from a robust and powerful immune system to a immune system that is unable to protect against even the simplest infections?
A common scientific opinion is that this immune decline is a direct result of thymus gland shrinkage  which results from a hormonal imbalance in the endocrine system, specifically, human growth hormone.
Research results have shown that shrinking thymus glands and subsequent immune function drop could be reversed. And HGH is the responsible hormone.
It is impossible to ignore the research findings which show that a depressed immune system is a treatable situation.
 Kelley, K.W., et. al. Proceeding of the National Academy of Science.
 Cittadini, A., et al. American Journal of Physiology.
 Clemmesen, B., et al. Osteoporosis International.
 Papadikis, M. A., et al. Annals of Internal Medicine.