Dietary Supplement. Non-Acidic. The better vitamin C. Gentle and non-acidic. Patented vitamin C formula. 100% vegetarian. With citrus bioflavonoids. 24-hour immune support. Ester-C is a breakthrough patented Vitamin C formula supported with naturally occurring metabolites. Metabolites help enhance the absorption of Vitamin C by your white blood cells an important part of your immune system. Ester-C s unique chemical-free manufacturing process neutralizes pH making it non-acidic and gentle on the stomach.