Ester-C is a unique breakthrough Vitamin C formula supported with naturally occurring metabolites. Metabolites help enhance the absorption of Vitamin C by your white blood cells, an important part of your immune system. Ester-C's unique, chemical-free manufacturing process neutralizes pH, making it non-acidic and gentle on the stomach. This product is gentle and non-acidic, providing 24-hour immune support. It contains no gluten, wheat, lactose, eggs, preservatives, yeast, milk or milk derivatives, soy, grapefruit, sodium or artificial color.