Researchers from the University of Toronto and University of Torino (Italy) have found potential health risks associated with titanium dioxide, a common skincare and sunscreen ingredient. Generally it is considered to be safe, because it doesn’t penetrate healthy skin, though, when titanium dioxide is exposed to ultraviolet light, it can exhibit toxic effects. In the Chemical Research in Toxicology study, a variety of forms of titanium dioxide, including anatase and rutile, were tested on pig skin to help design a safer ingredient for use in skincare. Rutile, a crystalline form, washed off easily and had little effect on the skin. On the other hand, anatase was difficult to wash off and damaged the outermost layer of skin even in low ultraviolet light. Damage was linked to free radicals and resulted in premature signs of aging. Researchers say, “The present findings strongly encourage the use of the less reactive, negatively charged rutile to produce safer TiO2-based cosmetic and pharmaceutical products.”