Thus, HGH is the latest and most effective treatment for Alzheimer's disease, although the large double-blind clinical trials have not yet been done. One consistent effect of HGH deficiency is irritability and when a person receives replacement therapy this reverts to a profound sense of well-being. Bone cells respond by making new bone and osteoporosis reverses, although this effect requires two or more years for completion. Fat cells respond by giving up their little lives as they are burned for energy. The weight gain around the middle which is so characteristic of HGH deficiency, melts away in a few months.
Muscle cells respond by becoming larger and stronger, especially in the upper body.
The strength and endurance of youth reappears. Many people are able to read without reading glasses again as the ciliary muscle of the eye becomes stronger again. Given the many function of HGH, it, more than any other hormone, determines the physical changes which are an expression of aging. Predictably, levels of HGH fall off progressively with age. The biochemistry of HGH is complex.