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®’has a neutral pH, making it non-acidic and gentle on the stomach. In a daily 1,000mg dose, Ester-C® delivers 24-hour immune support... so once a day is all you need. Added Citrus Bioflavonoids may help your body better absorb and utilize Vitamin C.