In a recent article in the Huffington Post it is stated that 80% of the vitamin C sold in the United States comes from China. This claim is hard to verify because most bottles of vitamin C merely state the company they are "distributed by" and often do not list a country of origin.
I have, however found some sources of vitamin C that I note did not come from China.
A quick chat with the customer representative from Swanson revealed that all their products are made in the USA, Europe or Japan.
In particular that means there are vitamin C is not from China.
I also happen to know that Shaklee does not manufacture and of its products in China.
Interestingly, Shaklee sells a form of vitamin C that is blended with iron to reduce the acidity and make its stomach-friendly.
Another stomach-friendly source of vitamin C is Esther-C, which is made in the United States.
Another option for vitamin C that is not from China is the Vitamin C Foundation, which sells vitamin C and powder form for easy consumption of large amounts, and which is manufactured in Europe.