Tetrahexyldecyl ascorbate is a lipid-soluble form of vitamin C, known as an ascorbic acid derivative. It's used in skincare products like creams, serums and anti-aging formulas for its antioxidant properties that can reduce the appearance of fine lines and wrinkles, promote collagen production and brighten complexion. Its lipid-soluble nature also allows it to penetrate skin more effectively and potentially provide longer-lasting benefits compared to water-soluble vitamin C derivatives.