Ascorbic acid is one form ( vitamer ) of vitamin C.It was originally called. -hexuronic acid, but, when it was found to have vitamin C activity in animals (vitamin C being defined as a vitamin activity, not then a specific substance), the suggestion was made to rename it. Heroin users are known to use ascorbic acid as a means to convert heroin base to a water-soluble salt so that it can be injected. 2  As justified by its reaction with iodine, it is used to negate the effects of iodine tablets in water purification.