How Do Physical and Chemical Sunscreens Differ?
Technically a sunscreen is composed of sun filters. These are agents that either block, deflect or reflect UV rays. And, many sunscreens often use a combination of both physical and chemical blockers to achieve optimal results. Physical filters include zinc oxide and titanium dioxide. They work by sitting on top of skin and either reflecting or scattering UV rays. Zinc oxide can block against both UVA and UVB rays, covering the whole spectrum, while titanium dioxide only delivers protection from UVB rays. Both ingredients work well, but have a tendency to leave a white cast on skin. Newer, micronized versions or those that contain nanoparticles appear much more clear on skin. Chemical filters include a range of ingredients including avobenzone (also known as Parsol 1789), oxybenzone, Tinosorb M, Tinosorb S, Mexoryl SX and Mexoryl XL amongst others. These agents work by interacting with the skin’s top layer to absorb UV rays and convert them into energy before they can harm skin. Chemic
