Hot topic: nanoparticles
Remember when lifeguards and beach-goers alike donned bright zinc stripes on their noses and, if they were really brave, beneath their eyes?
Ah, the good old days. Well – non-nano sunscreen like zinc is still possible to find, and can usually be identified by the white pasty look it leaves on the skin. It can’t, however, be identified by looking at the label.
In their larger particle form, the main active ingredients in sunscreen, zinc oxide and titanium dioxide, work by reflecting UV radiation. However, in nanoparticle form, they absorb UV radiation.
This results in a process called photocatalysis which produces free radicals as a by-product and they have the potential to alter DNA – but only if they reach past the outer layer of skin.
It’s this level of penetration that’s at the heart of the debate.
In August, two doctors