Ascorbyl stearate

Ascorbyl stearate (CAS 10605-09-1), also designated E304ii, is a fat-soluble ester of vitamin C used as an antioxidant in oil-based systems where water-soluble ascorbic acid cannot function effectively. It protects lipid-containing formulations from oxidative degradation, extending shelf life across food, cosmetic, and pharmaceutical products. In food manufacturing, it is incorporated into fats and oils.

It is used in fat-rich products such as margarine and baked goods to prevent rancidity and color deterioration. Cosmetic formulators use it in emollients, creams, and serums where it stabilizes the oil phase. The compound contributes antioxidant activity to the finished product. Pharmaceutical manufacturers apply it to lipid-based drug delivery systems and soft gel capsules to protect active ingredients sensitive to oxidation.

It also functions as a co-antioxidant alongside tocopherols in nutraceutical oil blends, improving overall oxidative stability. Ascorbyl stearate is supplied as a white to off-white powder for industrial use. It is available in food-grade quality meeting E304ii specifications under EU food additive regulations, as well as in pharmaceutical-grade quality conforming to USP or Ph. Eur. standards.

Bulk quantities are typically offered in fiber drums or multi-layer bags suited for temperature-controlled storage. This ensures the material remains stable and effective for various manufacturing applications.