Sunblock and sunscreen are not the same

BOSTON, Aug. 6 (UPI) -- Many people don’t realize there’s a difference between sunblock and sunscreen, a U.S. report advises.

Sunblock reflects the sun’s rays, thereby blocking the rays from reaching the skin, while sunscreen absorbs rather than reflects ultraviolet radiation, explains Skin Care and Repair, a Harvard Medical School report.

Sunblocks, such as zinc oxide and titanium dioxide, are highly effective in protecting against both UVA and UVB rays -- the types of ultraviolet radiation that cause sunburn and skin cancer.

Sunblocks often appear white on the skin, while sunscreens tend to be less visible. A major drawback of some sunscreen ingredients is they often break down after several hours of exposure to sunlight, which means they need to be reapplied.

The American Academy of Dermatology recommends using sunscreen with an SPF rating of at least 15, but those with fair skin or at high risk for skin cancer may want to go higher. The higher a sunscreen’s SPF rating, the longer it protects against sun exposure.

Products labeled “broad spectrum” often contain several different sun protection ingredients in order to cover a broad range of ultraviolet radiation, the report said.