>>5732563Many sunscreens use nanoparticle titanium dioxide which, despite reports of potential health risks, is not actually absorbed through the skin.
Sadrieh N, Wokovich AM, Gopee NV, et al. (May 2010). "Lack of significant dermal penetration of titanium dioxide from sunscreen formulations containing nano- and submicron-size TiO2 particles". Toxicol. Sci. 115 (1): 156–66