Our Vitamin C Serum is a combination of the most stable form of ascorbic acid. It contains Sodium Ascorbyl Phosphate (SAP) and Ethyl Ascorbic Acid. Both derivatives are super stable. They have antioxidant properties and enhance collagen production; in addition, they regulate sebum and deliver vitamin C deep into the skin. As compared to ascorbic acid, both derivatives are less likely to irritate the skin. SAP is a stable and water-soluble derivative of vitamin C; that’s why it is more popular in skin care.