Nutralife Ester C 1000Mg+Bioflavonoids Tablets 100 Vitamin C is essential for the proper function of the immune system and may aid in decreasing the duration of colds when taken regularly. Nutra-Life Ester-CÂ¬Ã† 1000mg + Bioflavonoids: - Provides 24 hour immune support, May aid in decreasing the duration of colds when taken regularly. Is a potent antioxidant. *in non-smokers. Ester-CÂ¬Ã† is a researched form of Vitamin C that supports natural immunity. Ester-CÂ¬Ã† may lead to a more sustained retention of Vitamin C in the white blood cells than ascorbic acid*. 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.