Titanium dioxide (TiO or CI 77891) is widely used; it's a whitening, pearling agent, making anything from cosmetics to toothpaste to paper to even organic nut milks sometimes appear white and luminescent. Titanium dioxide is a staple of most sunscreens on the market. But, alas, there are caveats. In sunscreen, it’s almost always in nanoparticle form. 'Nanos' can purportedly enter your bloodstream and alter DNA. In cosmetics, it can be in nanoparticle format, too. You may wish to avoid titanium dioxide just because you don’t like the risk of it being nano-sized atop mixed research findings. If you have sensitive skin that has reacted adversely to sunscreen and/or cosmetics in the past, then you may suffer a true allergy or sensitivity to titanium dioxide. Read more about titanium dioxide here and shop titanium dioxide-free in this collection: