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]
What are the risks?
The issue of risk comes down to two questions:
- Can nanoscale titanium dioxide as used in sunscreen products penetrate human skin and enter our bodies?
- If penetration is possible, how much exposure to this kind of sunscreen might produce health effects?
Some background would help. Nanoscale particles are very, very small, less than 100 nanometer (nm) in size.… Continue reading →