Sunscreen Vs. Sunblock - What's the Difference?

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

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

I recommend that you look for a sunscreen that protects you from UVA and UVB radiation. UVA rays are longer wavelengths tat penetrate more deeply into the skin are contribute to the development of skin cancer (and wrinkles), whereas UVB rays are shorter, cause burning of the skin, and also lead to skin cancer. Either a physical or chemical sunscreen can be used, the former being best for those with sensitive skin. Look for products that have SPF 30 or higher. Most people do not apply enough... more