What is a physical sunscreen? Plus, how it compares to other forms
No, it’s not a new SPF mechanism—physical sunscreen is just another way of saying mineral sunscreen.
This descriptor makes sense because mineral sunscreens manually block UV rays by creating a barrier on the skin (like a physical shield). Think of them as reflective glass: some of the rays hit the SPF filters and are reflected, protecting the skin below from damage.
Chemical sunscreens, on the other hand, absorb UV rays and cause a chemical reaction that then converts the UV rays into heat.
But as chemist George Zeidan wrote and previously told mbg , mineral sunscreens also absorb to some extent, just like their chemical counterparts. Basically, they work in two ways: first, by blocking some rays, and second, by absorbing the rays and channeling their damage into heat.
Currently, zinc oxide and titanium dioxide (mineral or physical sunscreens) are the only two ingredients that the Environmental Protection Working Group has determined are safe to use and effective in protecting skin from UV damage.
As long as the minerals aren’t nano-nano (read: not broken down into smaller pieces), they’re considered safe for the oceans because studies show they don’t cause coral bleaching or affect marine life—another worthy benefit.
However, mineral sunscreens are known to leave a strong white cast. That being said, there are plenty of sunscreen formulas on the market today with mineral ingredients, as well as tints and oils that minimize the chalky look—here’s a list of our current favorites if you’re ready to stock up.