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Posted: June 6, 2007
Consumer Report's first nanotechnology test
(Nanowerk News) Consumer Report, an independent nonprofit organization that tests consumer products, has been testing sunscreens for its July issue. Of the eight products tested for nanoparticles, all contained them, but the tests found no correlation between their presence and sun protection. This is the first time Consumer Report has been testing products containing nanotechnology.
Nanoparticles of zinc oxide or titanium dioxide are used in sunscreens because the normally white substances, which absorb ultraviolet radiation, become more transparent when the particles are nano-sized. Lab studies indicate that both of those nano-ingredients create free radicals that damage the DNA of cells and possibly cause other harm as well. And even low exposure to nanoparticles of titanium dioxide can damage the lungs of animals if inhaled.
But whether those particles in sunscreens pose direct health risks to humans depends mainly on whether they penetrate the protective outer layers of dead skin. Studies suggest they don’t reach live tissue under normal circumstances. But it’s not known whether skin damaged by acne, eczema, sunburn, or nicks from shaving is more vulnerable to penetration.
Consumer Report concludes that until there is adequate safety assessment, people who wish to avoid exposure to those nanoingredients could choose sunscreens that don’t list titanium dioxide or zinc oxide on their label. That wouldn’t require settling for less sun protection: The tests found no correlation between effectiveness and the presence of those ingredients. Moreover, the top-scoring U.S. product, Neutrogena Ultra Sheer Dry-Touch SPF 45, did not contain either zinc oxide or titanium dioxide.