Ester-C is the patented immune health formula that stays in your system for 24 hours - so you have the kind of support you can count on 24/7.*^ Ester-C is carefully formulated to contain naturally occurring metabolites. Metabolites are substance derived from other compounds (such as nutrients) during the process of metabolism. The metabolites in Ester-C help enhance the retention of Vitamin C by your white blood cells, which are a vital component of your immune system.* So once you take your daily dose of Ester-C, it gets into your white blood cells, and stays there for up to 24 hours, clinically studied to last longer than regular vitamin C.^ Plus, Ester-C is manufactured without chemicals to neutralize pH, which means it's non-acidic and gentle on your stomach. Patented Ester-C delivers 24-hour immune and antioxidant support so one serving a day is all you need.* Non-GMO No gluten, wheat, milk, lactose, artificial color, flavor or sweetener, preservatives, sugar, starch, soy, yeast, fish. Sodium free. Suitable for vegetarians. *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. ^Ester-C has been clinically studied to stay in the white blood cells for up to 24 hours, which is longer than regular vitamin C. White blood cells are an important component of the immune system.