Dietary supplement. Crystalline Vitamin C. TwinLab C-500 Caps are easier to swallow and assimilate. Well tolerated by most highly allergic individuals. No tablet binders, coatings or colorings. Free of the most common allergens such as soy, yeast, rice, barley, wheat, lactose (milk sugar) and all milk, citrus, fish and egg products. No added sugars, salt, artificial sweeteners, colorings, preservatives or salicylates. This product is manufactured at our own state of the art facility.