The June issue of the journal Skin Pharmacology and Physiology clarifies the scientific evidence base of the debate on nanoparticles in sunscreens. In an article entitled Nanotechnology, cosmetics and the skin: is there a health risk?, the authors Nohynek (L’Oreal) et al. summarised that ‘Sunscreens contain TiO₂ or ZnO nanoparticles (NP), which are efficient UV filters. A number of studies suggest that insoluble NP do not penetrate into or through human skin. The results of in vivo toxicity tests showed that TiO₂ and ZnO NP are non-toxic. In vitro and in vivo cytotoxicity, genotoxicity, photogenotoxicity, acute toxicity, sensitisation and ecotoxicology studies on TiO₂ NP found no difference in the safety profile of micro- or nano-sized materials, all of which were non-toxic.’

The abstract concludes that ‘the current evidence suggests that nano-sized cosmetic or sunscreen ingredients pose no potential risk to human health, whereas their use in sunscreens has large benefits, such as the protection of human skin against skin cancer.’

The study’s conclusion on the penetration of nanoparticles through the skin reflects the recently published findings of the NANODERM Project.