Nutra Life Ester-C 1,000mg with Echinacea and Vitamin D3 chewables provide 24 hour immune support and may aid in decreasing the duration of winters ills and chills.  Ester-C® is a researched form of Vitamin C that supports natural immunity and leads 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, and to whom Vitamin C may upset the stomach. Vitamin C is essential for the proper function of the immune system and may aid in decreasing the duration of colds when taken regularly.