Maybe because of findings like this...
http://www.medibolics.com/GHMuscle2.htm
"Several studies of HIV(-) subjects indicate that growth hormone does not increase the portion of the lean body mass (LBM) that is known as muscle, even though growth hormone does increase "lean body mass". Note that LBM describes several compartments of tissue that include muscle, connective tissue, bone, organs, and water, too. These studies found that the increase in LBM with growth hormone in HIV(-) subjects consists of tissue other than muscle. Actually the increase in LBM appears to be mostly water, with perhaps a little connective tissue, and some organ tissue, too. (It should be underlined that organ tissue, like muscle tissue, wastes in HIV, and rebuilding of organ tissue by growth hormone could be an important effect that may improve overall health and survival.)"
Serono studied their serostim to combat the side effects Lipodystrophy in HIV population. A re-distribution of fat around the trunk area and upper back. Since then, HIV cocktails have gotten much better in keeping patients healthier thus eliminating the waisting syndrome that is caused by AIDS. North Shore University Hospital, Manhassett NY. conducted a study in HIV + people, who were NOT advanced in there disease, a 16 week study of Serostim @ 18iu's p/d. They were looking to see if there were any lean muscle mass gained at 16 weeks. They did, a whole 3 lbs were gained on 18iu's p/d. No androgens at all were used. Just serostim. That is why it is so readily available on the street and nothing else is. Serono will never publish there findings because they know the cost of $1700 per kit, per week all for 3 lbs of lean mass will get them pulled of every Medicaid and ADAP formulary across the country for AIDS patients.