The FDA first approved the use of titanium dioxide in food in 1966, following its 1960 removal (along with the removal of other color additives) from the agency's original Generally Recognized as Safe list. In 1977, titanium dioxide joined the list of color additives that are exempt from certification, which means titanium dioxide doesn't have to be listed on the packaging of every product it's used in, Faber noted.

There are two primary forms of titanium dioxide commercially available: anatase and rutile. The rutile form is typically used in sunscreens due to its superior ability to handle UV rays and stability in the presence of UV light. The anatase form is typically used in other types of products, such as paint. Another plus of the rutile form is that its UVA protection extends past 400 nanometers, which is the upper limit of UVA.