It's quite common for expats to China to have hair loss. I met quite a few who were experiencing it in Guangzhou.
I really don't think shampoo will help. Eat healthy foods and try to relax...it grows back in eventually.
Try a hair tonic from the UK called Slivikrin. It worked for me when I was going through a lot of stress and had big bald patches (alopicia or something like that)
hey! try some vitamins Selenium plus Zinc. 2 pills a day for a month...after that, suplement 1 pill Iron for the next 10 days. You should get balanced like this.