Metal oxide sunscreens protect skin by absorption, not by reflection or scattering

@article{Cole2016MetalOS,
  title={Metal oxide sunscreens protect skin by absorption, not by reflection or scattering},
  author={Curtis Cole and Thomas Shyr and H Ou-Yang},
  journal={Photodermatology},
  year={2016},
  volume={32}
}
The inorganic metal oxide sunscreens titanium dioxide and zinc oxide have been considered to protect against sunburning ultraviolet radiation by physically reflecting/scattering the incident photons and thus protecting the skin. Earlier publications suggested, however, that the primary action of UV protection by these sunscreen agents is through absorption and not by reflection. The purpose of this work was to quantitate the contributions of each of these modes of action to the protection… 
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