Ester-C® is a breakthrough patented 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. In a daily 1,000 dose, Ester-C® delivers the active immune system support and powerful antixoidant protection you can depend on. Added Citrus Bioflavonoids may help your body better absorb and utilize Vitamin C.