t's long been known that titanium dioxide (TiO2) and zinc oxide (ZnO) block the harmful effects of ultraviolet light - the stronger the sunblock the whiter the lotion, with total sunblocks becoming a thick white paste.
But when you break down these substances to nano-sized particles, they become transparent. So you get the beneficial effect without the 'face pack' look.
So when you see a high-factor sunscreen in a moisturiser or sun cream which is clear, not white, you know that it is nano.
This use of nano-sized TiO2 and ZnO2 in sunscreens and moisturisers is one of the largest uses of nano in the cosmetics and personal care markets