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Sunscreen Works Best When Used Everyday, Everywhere

Oct. 13, 2000 -- Do you slather on sunscreen only on the weekend or before outdoor activities and still feel protected? You might be fooling yourself, but you're not fooling your skin, according to research published in the October issue of the Journal of The American Academy of Dermatology.

In the first study to look at the inconsistent use of sunscreens, experts have found that the daily application of a sun protection product is your best defenses against skin aging and cancers.

"Missing sunscreen application for even one day can cause skin damage," lead author Tania J. Phillips, MD, professor of dermatology at Boston University School of Medicine, tells WebMD. "Sunscreens should be used as part of a sun-avoidance strategy including protective clothing, staying in the shade, and avoiding the sun from 10 a.m. to 2 p.m."

"This is an interesting study and it confirms what I've known all along," Rodger B. Haglund, MD, dermatologist at the Haglund Clinic in Abilene, Texas, tells WebMD. "Patients don't do what they're told, and when they don't, they aren't going to get as good results as if they followed directions. I advise sunscreen all the time, but the problem is that those that take me seriously are those that already have problems. Unfortunately, this isn't going to do as much good as if they started earlier in life."

In their study, researchers recruited 24 healthy women for their study who were between 20 and 55 years old. Three sunscreen products were applied to each woman on areas not typically exposed to the sun, using various products in various strengths -- SPF 15 or SPF 29 doses. The products were applied daily or intermittently. In some areas, sunscreen products were used. Study participants were exposed to ultraviolet (UV) light for four consecutive days.

After skin samples were taken and analyzed, investigators found a significant increase in the number of sunburned cells and skin inflammation when sunscreen application was missed, compared with when the product was applied daily. In addition, researchers found that daily application of a product with protection factor of SPF 15 was an even better safeguard than the occasional use of higher SPF products.

"Our study shows that for sunscreens to be maximally effective in preventing skin damage [from the sun], they must be applied properly, regularly, and in appropriate amounts," the authors write.

The amount of sunscreen that should be applied depends on the sun exposure and the amount of time a person will be in the sun, Haglund says. If you're going to be out in the direct sun or if you have very fair skin, "you need to put on a lot. It would not be hard to go through several ounces in a day" he says, "if it's being applied the proper amounts. If you're going to be out in the sun for longer periods of time, be sure to apply more sunscreen and apply it more frequently," he adds.

Also, several products are now available that combine moisturizer or makeup with sunscreen, Haglund says, "which is an excellent idea."

So tomorrow morning, start your day with a protective coat of sunscreen -- whatever your plans. Your skin will thank you.