Some creams, lotions and sunscreens now contain tiny nanoparticles that can "penetrate the skin, swarm through the body and overwhelm organs like the liver."

This relatively new cosmetic component is beginning to create 'nanophobia' according to an article in the NYT yesterday. Nanophobia is "the fear that tiny components engineered on the nanoscale — that is, 100 nanometers or less — could run amok inside the body. A human hair, for example, is 50,000 to 100,000 nanometers in diameter. A nanoparticle of titanium dioxide in a sunscreen could be as small as 15 nanometers."

See their discussion about the unregulated use of nanoparticles in the cosmetics industry here.