Ester-C is a researched form of Vitamin C that supports immune system health. Ester-C may lead to a more sustained retention of Vitamin C in the white blood cells than ascorbic acid in non-smokers. It is a non-acidic form of Vitamin C and may be better tolerated than standard Vitamin C in people who are sensitive to acidic foods.Nutra-Life Ester-C + Bioflavonoids provides 24 hour immune support and decreases the duration and severity of common cold symptoms. The 24 Hour Vitamin C 806mg of Vitamin C per tablet Non-acidic, Researched form of Vitamin C Bioflavonoids AUST L 284792 Nutralife ESTER-C + Bioflavonoids Tab X 100.