Ester-C Bio by Klaire Labs contains a buffered form of vitamin C with bioflavonoids. Ester-C is a non-acidic form of vitamin C created by a unique process resulting in a patented mixture of calcium ascorbate and vitamin C metabolites. Contains a combination of different bioflavonoids complements the action of the Ester-C calcium ascorbate in this formula. Contains Pycnogenol Pine Bark