Perhaps no other hormone in the body is subject to more misconceptions than is human growth hormone (GH). If you are to believe the many claims repeatedly made on numerous websites and blogs, as well as that often voiced by various "anti-aging clinics," GH is a miracle hormone that can set back the aging clock. Growth hormone is also attractive to bodybuilders and athletes because of its reputed anabolic properties. Again, some self-styled web "experts" often proclaim that GH is the most anabolic of all hormones. Most such people are often associated with illicit steroid sites that just happen to sell GH and insulin-like growth factor-1 (IGF-1), which is a product of GH produced both in the liver and in other organs and tissues, including muscle. Since IGF-1 is a very expensive hormone when it's the real stuff, the likelihood that you're purchasing actual IGF-1 from some Internet site that works out of a post office box in the Netherlands is remote at best. But that's another story. The primary attractions to GH usage are to either help build muscle and lose body fat, or to forestall the aging process and hopefully recapture some of the features of youth, such as thicker skin, fewer skin wrinkles, lower body fat levels, and more muscle mass. Bodybuilders are convinced that GH not only is a potent anabolic hormone but also helps to dramatically lower body fat levels. I recall a story passed around in various Internet bodybuilding forums in the 90s about how you can consume as much as 10,000 calories a day and not gain any fat if you are also injecting GH.
The actual truth about GH for bodybuilding and athletic purposes is considerably less dramatic than the many rumors that abound about this hormone. In fact, using the word "hormone" in reference to GH is itself a mistake, since GH is actually a "family" of about 100 hormones varying slightly in size, referred to as isoforms. The main form that circulates in the blood, however, is one particular form that weighs in at 22 kilodaltons. The primary importance of knowing this is that scientists have tried to come up with a drug test for GH for the last 25 years or so, and thus far have come up empty. Much of this is related to the ephemeral nature of GH. GH is produced in the pituitary gland in the brain, which is 8% GH by weight. But the primary impetus for GH production in the pituitary is the release of growth hormone-releasing hormone (GHRH) from the hypothalamus structure in the brain. Another protein produced in the brain and gut, somatostatin, works to oppose the release of GH. The primary reason . . .