A sunscreen-tanning compromise: 3D visualization of the actions of titanium dioxide particles and dihydroxyacetone on human epiderm

The self-fanning agent dihydroxyacetone (DHA) was applied to human skin sam ples, and its effect on light absorption was followed in time to study the DHA influence inside the different layers of skin. Application of DHA shows increased light absorption in the visible light region, as evidenced by sk in taming, The tanning effect is enhanced by UV irradiation and appears loc alized in the near-stratum corneum layer as revealed by depth analysis of t he time signal. As a reference, application of an emulsion containing titan ium dioxide particles shows clear surface stability and a screening of ligh t penetration beyond the stratum corneum.