July 22, 2013
By Kenneth Portier, PhD
Recently, manufacturers have introduced new sunscreen products that use titanium dioxide, a typical ultraviolet (UV) radiation blocker found in many sunscreens, formed into tiny nanoscale particles. Why use nanoscale titanium dioxide? Because at this small size the particles do not block visible light, and therefore the sunscreen is invisible when applied to the skin and at the same time provides protection from cancer-causing UV radiation.
Titanium dioxide is an excellent UV-blocker, but there has been some concern about its safety because in dry powder form, titanium dioxide is highly toxic when inhaled. The International Agency for Research on Cancer (IARC) classifies the dry powder form of titanium dioxide as possibly carcinogenic to humans.
It's not yet clear, though, whether other forms of titanium dioxide, such as the nanoparticles used in sunscreen, also pose a risk. More...