Some people have digestive problems when supplementing with vitamin C.
Vitamin C, (ascorbic acid), is available in many forms. Mineral salts of ascorbic acid are buffered and, therefore, less acidic than pure ascorbic acid. Some people find them less irritating to the gastrointestinal tract than ascorbic acid. Sodium ascorbate and calcium ascorbate are the most common forms and are regularly compounded, although a number of other mineral ascorbates are available.