The 411 on Sunblock vs. Sunscreen: Which One Should You Use?

It didn’t take long, but now the summer heat is upon us. Whether you are young or young at heart, it’s important to protect your skin from the sun’s rays. It’s a grim statistic, but skin cancer is the most common form of cancer in the United States1, and one in five people will develop skin cancer during the course of a lifetime2.

So as the sun comes out, so should your sunscreen. Or should it be sunblock? What’s the difference, and is one really better than another?

Sun protection comes in two forms: sunscreen and sunblock, and many people do not know the difference. Both work to protect the skin from the sun’s damaging UV rays but in different ways.

“Sunscreen works just as the name implies, as a screen,” said Kendall Roehl, MD, a plastic surgeon on the medical staff at Baylor Scott & White. “It is colorless and absorbed into the skin to reflect and screen the skin from damaging UV rays. Sunblock physically blocks the sun’s UV rays from penetrating the skin, acting as a barrier.”

Many of us remember those years as kids, when our mothers would slather our noses with white (or pink if you were lucky – and female) zinc oxide, the most visible example of a good sunblock. Sunblocks contain either zinc oxide or titanium dioxide and protect the skin against both UV-A and UV-B rays. Sunscreen is white but is absorbed into the skin when applied and becomes transparent. When purchasing a sunscreen, check to see if it covers both UV-A and UV-B rays. Most sunscreens only cover UV-B rays.

Both sunscreen and sunblock are packaged based on SPF or sun protection factor. This is a number to give you some indication of the duration of protection.

“Choosing sun protection with a high SPF is always the smart choice,” Dr. Roehl said. “For example, SPF 15 sunscreen/sunblock will allow you to be in the sun 15 times longer than it would normally take to get a sunburn. So if your skin burns in 10 minutes without protection, then SPF 15 will give you 150 minutes of coverage. For most instances, SPF 15 up to SPF 60 is adequate depending upon the length of expected exposure.”

Remember to reapply every hour when participating in water activities or after excessive sweating.

So, when you get ready to head outside for some fun in the sun, make sure you are prepared and do your homework! Read the labels and make sure you have what you need to protect your skin. And don’t forget the floppy hat and sunglasses. The more protection you can give yourself while you are outside the better. The same thing goes for the kids. Make sure to slather on the sunscreen and sunblock, and help them learn early to keep themselves safe from the sun’s potentially harmful rays.

1 American Cancer Society. Cancer Facts & Figures 2009
2 JK Robinson. “Sun Exposure, Sun Protection, and Vitamin D,” JAMA: The Journal of the American Medical Association (2005): 294, 1541-­‐43.

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The 411 on Sunblock vs. Sunscreen: Which One Should You Use?