What is the science behind significant age reversal?

Studies in the New England Journal of Medicine and other journals show that increased levels of Human Growth Hormone (HGH) may reverse biological aging. HGH is a natural hormone in the body, but after about age 20 our bodies produce less and less, leading to increased body fat, decreased immunity, poor skin tone, decreased libido, and other symptoms usually associated with aging. Some increase in HGH levels can be achieved naturally by exercise, careful attention to diet, and reducing body weight to optimum levels. Injections of pure HGH, which are very expensive and risky, have been used therapeutically in growth hormone deficient individuals, and have been used to raise HGH levels to artificially high levels in otherwise healthy adults. With advanced, proven nutritional supplementation, you can experience the benefits of increased HGH levels safely and inexpensively.