Description Ester-C brand of Vitamin C is a unique form of Vitamin C containing naturally occurring Metabolites. Ester-C's manufacturing process neutralizes the pH, making Ester-C gentle and easier on the digestive system unlike other Vitamin C products which are highly acidic. Ester-C is a unique ascorbate complex bound with Calcium Carbonate. It is naturally processed in purified water, without the use of alcohol or acetone solvents.