Many people assume that any product sold in a health food store is natural. Actually, most of the vitamins and minerals as well as hormone products and many other items other items are synthesized in a lab. This includes the majority of vitamin C products sold in health food stores.
Natural vitamin C is too costly to extract. Therefore, the majority of vitamin C is synthesized from sugars, most often from corn. This includes products, such as palm C, which sounds natural. Palm C is not an extracted C though, it is synthesized from palm sugar.
Synthetic vitamin C will be listed on the bottle as ascorbic acid. Natural bioflavonoids are frequently added because they aid in the function of vitamin C. Bioflavonoids occur naturally in natural sources of vitamin C such as berries.
Some companies buffer the acidity of the ascorbic acid with minerals. Examples are calcium, sodium and magnesium ascorbates. These are beneficial for people who cannot tolerate the acidity of the ascorbic acid. Although, I generally prefer non buffered forms of vitamin C if not natural. The majority of people have insufficient levels of stomach acid to digest and absorb nutrients. Non buffered vitamin C increases stomach acidity aiding in digestion and absorption when taken with meals.
Synthetic vitamin C is extremely unstable and quickly decomposes when exposed to light, heat or moisture. Therefore, synthetic vitamin C should be kept in a cool, dry, dark place. I do not recommend storing bottles of vitamin C in a refrigerator though. Doing so can cause moist air to condense inside the bottle making a wet mess and destroying the vitamin C. Storing the vitamin C in a pantry would be a better choice.