I've been lived in China for 15 years. Although most Chinese do not have a tendency to develop hypomuscular physique/ or even hate big guys (LOL), there are still dedicated bodybuilders there.
You can find Optimum, Champion, Muscletech etc in China as well. The price varies greatly due to price discrimination. Some are overpriced for those rich ppl, some are ok.
There are many professional BB website in Chinese as well; they offer online sale of supplements.
The most convenient way to get supplements in China is to ask a trainer in some big gyms (powerhouse, Golden Time, Gold's, etc) But they are generally overpriced.
If your friend wants some supplements, he can go to this site:
www.dabin69.com
IF AND ONLY IF HE CAN UNDERSTAND CHINESE, LOL
That site is owned by one of my friends, who is one the leaders in BB industry in China.
Anyone else wants more info for modern China?