The credibility of cosmetic claims: even big boys such as L'Occitane and L'Oreal were penalized for misleading claims: http://www.acs.org/content/acs/en/pressroom/presspacs/2016/acs-presspac-may-11-2016/how-cosmetic-companies-use-science-to-back-up-product-advertising.html
American Chemical Society
How cosmetic companies use science to back up product advertising - American Chemical Society
American Chemical Society: Chemistry for Life.
another reason to avoid nano-sized TiO2: http://www.cosmeticsdesign-europe.com/Formulation-Science/Research-points-to-nano-sized-titanium-oxide-contributing-to-oxidative-stress
cosmeticsdesign-europe.com
Research points to nano-sized titanium oxide contributing to oxidative stress
Nano-sized titanium oxide (TiO2) is commonly used in a range of sunscreens, but new research is investigating its subtle effect on the oxidative stress process at a cellular level.