What is this amazing substance, HGH?
As its full name suggests, HGH is a hormone. Ernest Starling coined the term "hormone" in his paper, "On the chemical correlation of the functions of the body" in 1905.

A hormone is a substance made in one part of the body that can affect the activity of cells in another part of the body, sometimes even in a remote part of the body. In a way, hormones are like messengers, carrying a message from a gland, for example, to other cells of the body, instructing them to effect a particular activity. In the case of HGH, as long as the levels are not excessive, the message is all good news.

HGH is produced in the anterior (front) pituitary gland, which is located at the base and towards the center of the brain, back in behind the eyes. The pituitary is one of the endocrine glands, which means it secretes its "message" directly into the bloodstream.

Once HGH is released into the bloodstream, much of it attaches to receptors on the liver and instructs it to produce a protein called Insulin-Like Growth Factor-1 (IGF-1). It is in this form that HGH does much of its work. Both HGH and IGF-1 have receptor activity on our cells. Much of our IGF-1 attaches to binding proteins of which there are several, and each of these combinations have effects on cell function.

It is by attaching to the appropriate receptor sites at cells throughout the body that HGH and IGF-1 bring about their anti-aging effects. The gene for HGH is on the long arm of chromosome 17 in a cluster of five genes, while that for IGF-1 is on the long arm of chromosome 12.