This was eye opening article:http://drcranton.com/hrt/cautions_generic_HGH.htm
This M.D. said that HGH is fragile and "a large, highly complex protein molecule. Its long chain of more than 190 amino acids must be folded and wrapped into a unique 3-dimensonal configuration."
He then goes onto say that "molecules can become hooked together as dimers and polymers. Such impurities can cause immune responses and allergy to HGH, potentially cross reacting and neutralizing endogenously produced HGH from the pituitary gland. Proper extraction and purification are complex and expensive. Without great care, tiny residues from the cell culture broth can contaminate the end-product."
He then recommends Sandoz' new product as they are a large company that, according to him, has a good reputation for quality control.
I'm just mentioning it, because we had someone recently interested in growth hormone, so I thought I'd post this. I am sure there are others out there as well...