Sunscreen Vs. Sunblock - What's the Difference?

When people talk about physical sunblock and chemical sunscreens, I don't understand how they are different.  Which one works better? 

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+5

Sunscreen and sunblock - it depends whether you want a tan or not

Kenneth A. Arndt, MD, clinical professor of Dermatology at Harvard Medical School, Boston, wrote in the current "Bottom Line Personal" that sunscreen and sunblock are not the same. Sunblock is opaque and blocks almost all of the sun's UVA and UVB rays. It consists largely of zinc oxide and titanium dioxide. Sunblock does not have to be reapplied every few hours. Sunscreens are less visible on the skin and are designed to protect against UVA, UVB, or both. They do allow some... more
Michael A. Persky, MD
Los Angeles Facial Plastic Surgeon
+5

Sunblock v. Sunscreen

The term "sunblock" has been misleading and will soon be done away with. The question of chemical versus physical block is important. Chemical sunscreens are often unstable after exposure to UV light and degrade over time. Some of the better spectrum coverage ingredients include Avobenzone (Parsol 1789) and mexoryl / helioplex / ecamsule. The better physical blocks are zinc oxide and titanium dioxide with zinc being superior in broad spectrum protection. These physical blocks... more
Shawn Allen, MD
Boulder Dermatologist
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