It starts life as corn syrup, pure refined corn sugar!!
Which has attracted a lot of bad publicity lately, in my opinion for the right reasons. Then it goes through the seven step process below before being sold as vitamin C.
A Starch Hydrolysis: Corn syrup is broken down into simple sugar by heating it in the presence of enzymes.
B Hydrogenation: The product from step A is converted into D-Sorbitol.
C Fermentation: D-Sorbitol is converted into L-Sorbose.
D Acetonation: Acetone, the product in nail polish remover and paint striper is added to the L-Sorbose.
E Oxidation: The product from step D is then oxidised, acidified, washed and dried forming L-Gluconic Acid.
F Hydrolysis: L-Gluconic Acid is treated with hydrochloric acid (one of the strongest acids) forming crude ascorbic acid.
G Recrystallization: The ascorbic acid then ground into a powder.
This powder can legally be called vitamin C, even though it is made in a factory and is missing 80% of what makes up natural food state Vitamin C. The Nobel Prize winner Dr. Albert Szent-Georgi who discovered Vitamin C is reported to have said that “ascorbic acid simply cannot confer vitamin activity.”
Quite simply the body does not see the chemical construction of ascorbic acid as a foodstuff and thus the benefit on the body is minimal, not to mention the toxic acidic load it brings with it. In comparison, the company that I use personally, extracts the vitamin C from acerola cherries or citrus pulp depending on the product, dries it to retain the goodness; and that's it. This is not one long plug for a particular supplement company, there are many of suppliers of WHOLEFOOD or food state supplements worldwide and the list is growing.