How does Zinc Oxide work in terms of UV protection?
Zinc Oxide is an excellent sunscreen because it has the broadest UV protective spectrum and cannot be absorbed into your blood, unlike all the petroleum-based sunscreen chemicals. It sits on the top of your skin where it needs to be, effectively providing a layer of armor against damaging UV rays.
Zinc Oxide is, however, an extremely misunderstood active ingredient in the suncare industry. Most manufacturers, dermatologists and media report that zinc oxide reflects and scatters UV radiation, an assumption they make because it looks white. This is completely wrong. It looks white because it does indeed reflect and scatter visible light, however it behaves entirely differently in the UV spectrum. It would look black in the UV spectrum because it absorbs UV radiation via a process of electron excitation called band-gap absorption. Since energy always has to go somewhere, and UV is quite strong, zinc oxide absorbs UV and turns it into comparably harmless infrared, which it disposes of as heat.
Comparably, one of the issues with titanium dioxide is that although it absorbs UV, it cannot convert it as easily into heat, instead dumping the absorbed energy on nearby electrons and creating free radicals that cause oxidative damage to your DNA and other critical cellular structures.
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