Sunscreen Clothes: Do They Work?

July 19, 2012 -- It's America's hottest of summers, but do you really need more than sunscreen and a hat to protect yourself from the rays?

A whole new category of products are now available that include clothes, makeup and shampoo -- all promising to offer extra protection from the sun. There are even bikinis.

"For the life of me, I don't know what good that will do," Dr. David Leffell, a professor of dermatology at Yale University, told ABC News. "By definition, most of the body is uncovered, so the rationale of sun-protective clothing in the bikini escapes me."

While the shampoo doesn't protect the scalp at all, the good news is that chemically treated clothes work and Dr. Melda Isaac, a Washington, D.C., dermatologist, routinely recommends them to her patients.

"Let's face it, none of us really apply the right amount of sunscreen," she said. "Good sun protective clothing assures you of getting the proper protection."

ABC News tested a polo shirt rated UPF 50 and a child's hoodie rated UPF 20 in a certified lab. The results were that the garments worked as advertised when they were brand new.

However, the clothing did lose some effectiveness after three or four washes, which made our experts believe they are unlikely to last more than one season.

"A year or two would be a very good standard for the longevity of a fabric," said Leffell. "The protection doesn't last forever, and you don't want to take things out of storage every summer and assume that you're being protected."

Detergent that adds chemical sunscreen to your regular clothes also proved to be effective. What does not work is a plain, white untreated t-shirt. It offers only SPF 8 protection -- a sunburn waiting to happen. But when treated with a detergent that includes a sunscreen additive, the SPF increases to 15.

A cheaper alternative to all this remains sunscreen and dark clothes that deflect UV rays.

"If someone would actually want to wear denim on the beach, that would offer the best sun protection, but obviously that's going to be warm," said Isaac.

If not, there's always the sunscreen-treated bikini, it passed the test with an SPF of 50 but, of course, you'll need an awful lot of sunscreen for the rest of you.