Anyway, it doesn't matter if it reflects or absorbs, Titanium Dioxide is a pretty awesome sunscreen agent for two main reasons: it gives a nice broad spectrum coverage and it's highly stable. Its protection is very good between 290 - 350 nm (UVB and UVA II range), and less good at 350-400 nm (UVA I) range. Regular sized Titanium Dioxide also has a great safety profile, it's non-irritating and is pretty much free from any health concerns (like estrogenic effect worries with some chemical filters).
if you compare the levels—which went as high as 50,000 milligrams/killigrams per day— to what humans are actually exposed to, we're talking orders of magnitude. It was a huge amount, Norbert Kaminski, PhD, a professor of pharmacology & toxicology and director of the Center for Research on Ingredient Safety at Michigan State University told Health.
The main food categories contributing to dietary exposure of E171 are fine bakery wares, soups, broths and sauces (for infants, toddlers and adolescents); and soups, broths, sauces, salads and savoury based sandwich spreads (for children, adults and the elderly). Processed nuts are also a main contributing food category for adults and the elderly.
Titanium dioxide comes in the form of a white powder and is sometimes used in cosmetics to adjust a color to a lighter shade. This is also why it can produce a white cast.