Human Growth Hormone is an injectable hormone that can be administered subcutaneously or intramuscularly. When injected subcutaneously, HGH carries a bioavailability of approximately seventy-five percent. When injected intramuscularly, HGH carries a bioavailability of approximately sixty-three percent. The mode of administration will also affect the half-life of the Somatropin hormone. When injected subcutaneously, it will carry a half-life of approximately hours. When injected intramuscularly, it will carry a half-life of approximately hours. While this is a rather short half-life regardless of the mode of administration, keep in mind the total effects far outlast these numbers due to the pronounced and significant increases in IGF-1 production that stretch far past the twenty-four hour mark.
Claims for GH as an anti-aging treatment date back to 1990 when the New England Journal of Medicine published a study wherein GH was used to treat 12 men over 60.  At the conclusion of the study, all the men showed statistically significant increases in lean body mass and bone mineral density, while the control group did not. The authors of the study noted that these improvements were the opposite of the changes that would normally occur over a 10- to 20-year aging period. Despite the fact the authors at no time claimed that GH had reversed the aging process itself, their results were misinterpreted as indicating that GH is an effective anti-aging agent.    This has led to organizations such as the controversial American Academy of Anti-Aging Medicine promoting the use of this hormone as an "anti-aging agent". 
I’m a adult male, age 61 living in Ca. In 2006 I had a extensive brain injury which dialed me & affected my hgh levels severely. The rehabilitation center who re-trained me had my hgh levels tested with the result of 61 & W/C didn’t want to address the problem. It would be too expensive & lengthy for me to take injections now but do you feel your information above could help my cause? I just saw your article & questioned the possibility of improved health. I’ll check my e-mail in the next few days to see your response if any. Thank you for your time,SRG.