Synergistic immixtures of ascorbic acid with at least one monosaccharide ester of ascorbic acid and/or at least one metal salt of phosphorylated ascorbic acid more effectively increase the synthesis of epidermal ceramides in human skin, especially types IV to VII ceramides, as well as improve the barrier function, moisture content and/or suppleness/surface appearance of the skin and which otherwise combat/prevent intrinsic aging thereof and are useful for the treatment of dermatitis.