Nourish your immune system with our unique Ester-C, a gentle, non-acidic form of Vitamin C that provides all-day support.** Vitamin C is an antioxidant vitamin that is important for the functioning of white blood cells, which are vital components of the immune system.** Clinically studied Ester-C stays in your white blood cells for up to 24 hours, lasting longer than traditional Vitamin C.** Vitamin C supports healthy immune function and promotes our overall well-being.** While many animals naturally produce this essential vitamin, humans cannot. Thats why its important to get our Vitamin C from citrus fruits, certain vegetables, and supplements. Beyond potent antioxidant support and advanced active immune support, Ester-C also supports upper respiratory and heart health.** Whats more, this formulation includes eight essential vitamins, minerals, and herbs. Vitamin D, Zinc and Vitamin A further help maintain a healthy immune system.**