Consumer Reports puts sunscreens to the test

Sunscreen is essential on hot and sunny days. Sunscreen can protect us from skin cancer, as well as wrinkles and brown spots.

There are a lot of options when buying sunscreen.

A new survey from consumer reports finds that only 50 percent of us use it. And that even people who regularly use sunscreen don't always have a good understanding of what they're buying. Consumer Reports tested dozens to find out what you need to know.

"People look at the SPF, or sun protection factor, and that's very important, but it's only one part of protecting your skin from the sun," explained Trisha Calvo, Consumer Reports Health editor.

RELATED: GMA: Consumer Reports rates sunscreens performance

The SPF is a measure of how well a sunscreen shields your skin from UVB rays, which penetrate the top layer of skin and are the chief cause of sunburns. UVA rays penetrate deeper into the skin and can contribute to wrinkles. Both UVA and UVB rays can increase the risk of skin cancer.

"Consumer Reports recommends using a broad-spectrum sunscreen so you're protected against both kinds of rays," she said.

Consumer Reports tested over 60 sunscreens to see whether they deliver the protection they claim.

In the UVB tests, technicians apply sunscreen to panelists' backs and have them soak in a tub for 40 or 80 minutes, depending on the product's water-resistance claim. Then the area is exposed to UVB light. the next day, the test area is examined for redness.

More than 40 percent didn't have the SPF they promised.

To check UVA, technicians pass UVA light through sunscreen samples. Again, some had problems.

But Consumer Reports found some sunscreens aced the tests and are a good value.

Among the best are Pure Sun Defense SPF 50 for about $6, Equate Ultra Protection SPF 50 for about $8 and