Not nearly impossible... just have to know which pharmacy will sell them to you in Hong Kong.
There are 2 version for China. One for Hong Kong and 1 for mainland China. Every mainland version I have come across was counterfeit. Labelled generic... That is why the Hong Kong version can only be trusted if you get it from the pharmacy. There are 4 pharmacies I know that will provide to "foreigners" if you are a local Chinese, they will not provide to you in the case they get in the shits. Many underground HGH is from Global Anabolic (GLOTROPIN). Euro Hormones is an example.