Nature's Bounty Immune 24 Hour + with Ester-C Vitamin C provides advanced, long-lasting immune support to help keep you healthy.(1) With 1,000 mg of Ester-C, the clinically studied immune supporting ingredient, is the only Vitamin C that stays in your white blood cells for up to 24 hours, providing immune support around the clock.(1) Highly bioavailable Ester-C can increase Vitamin C levels in the body, which is important for white blood cell function, as white blood cells play a vital role in the immune system and contribute to the health of the upper respiratory tract.(1) For additional wellness benefits, Nature's Bounty Immune 24 Hour + rapid release softgels contain Vitamin D, Vitamin A, plus Zinc for extra immune and antioxidant support.(1) In addition, the immune-supporting formula is Non-GMO, and free of artificial flavors, artificial sweeteners, sugar, starch, milk, lactose, soy, gluten, wheat, yeast, fish, and sodium. The Vitamin C 1000mg supplement also includes herbal ingredients Elderberry and Echinacea, plus 9 essential nutrients for your overall health.(1) (1)These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.