Re: why supplements aren't working.

The european plant sources its materials from genetically engineered sources and that manufacturer could not guaranty gmo free raw materials.

The european gmo free standard allows <.9 gmo.

The only other sources are from china which are all gmo.

I believe they are making it at DSM which is probably using Scottish Crop Research which is a pro gmo company.

Methods of manufacture (chemical synthesis)

Vitamin C is produced from glucose by two main routes. The Reichstein process developed in the 1930s uses a single pre-fermentation followed by a purely chemical route. The more modern two-step fermentation process was originally developed in China in the 1960s, uses additional fermentation to replace part of the later chemical stages. Both processes yield approximately 60% vitamin C from the glucose feed.^[8]

Research is underway at the Scottish Crop Research Institute to create yeast micro organisms to synthesise ascorbic acid in a single fermentation step, a technology which is expected to reduce manufacturing costs considerably.^[9]

World production of synthesised vitamin C is currently estimated at approximately 110,000 tonnes annually. Main producers today are BASF/Takeda, DSM, Merck and the China Pharmaceutical Group Ltd. of the People's Republic of China. China is slowly becoming the major world supplier as its prices undercut those of the US and European manufacturers.^[10]

http://en.citizendium.org/wiki/Ascorbic_acid