http://www.fox13news.com/health/144531122-story 

TAMPA (FOX 13) – When it comes to sunscreens, we all know the drill. Use a broad spectrum SPF 30 or greater, and slather on a shot glass full.  New research is helping prove its benefits and show sun bathers what dangers they might face.

“It’s the first solid data that we have that is not only prevents sunburns, but prevents that bad cancer melanoma,” said USF Health Dermatology chairman, Dr. Neil Fenske, who was not involved in the study, but reviewed it with FOX 13 News.  A different study in Consumer Reports, may change how we get that protection.

Sunscreens can be divided into two groups: physical and chemical.

Physical sunscreens coat the skin, blocking harmful rays before they reach your skin. On the label, you’ll see minerals zinc and titanium.

Chemical sunscreens contain ingredients like avo- or oxy-benzone, mexoryl, and salates – a chemical cousin of aspirin. They penetrate your skin, filtering and absorbing harmful rays.

In the Consumer Reports testing, sunscreens were evaluated on small patches of skin after immersing it in water.

“It surprised me to hear that the physical screens did more poorly than the chemical screens, that probably absorb into the epidermis and stay there, whereas the physical ones tend to kind of wash off and dilute,” Dr. Fenske explained.

That dilution dropped a Banana Boat SPF 50 down to an SPF of 8. While that example was extreme, Dr. Fenske said there is no reason to toss your favorite brand.

“It doesn’t mean that they’re bad. It means that, when in water, it’s not as effective as they thought,” he explained.

He suggested bumping up the SPF when swimming – to compensate for the loss and boost effect by letting the sunscreen dry.

“I recommend, if you’re going to the beach, you put your sunscreen on at home. That helps prevent the running down in the eyes and the irritation, because you can pat the excess off,” he demonstrated.

While sprays are convenient, Dr. Fenske said the FDA isn’t sold. It begins with concerns you could miss spots and inhaling the product might cause problems for some.

Dr. Fenske said there’s another problem, “they’re flammable. If you’re putting a spray sunscreen on and you’re having a barbeque, and you’re near a barbeque fire, there have been serious burns.”

While he emphasized UV-protective clothing for kids, in and out of the water, parents can use physical sunscreens on children over six months. Babies under that age are best kept indoors.

“Their skin isn’t fully developed yet, their melanocytes aren’t fully producing pigment. They can’t even let you know if they’re getting too much sun,” he said.

A sunburn on a small child can increase their lifetime risk of melanoma and cause heat stroke.

As for chemical sunscreens, The Environmental Working Group has concerns about certain ingredients, like oxybenzone, that may affect hormones. Generally speaking, sunscreens made for children are physical ones.