Choosing the appropriate Sunscreen SPF for your skin

A new study from the Northwestern Medicine found that consumers find the terminologies and labels on sunscreen bottles, such as “UV-A,” “UV-B,” and “water-resistant” as well as their various numbers, to be confusing.

In a study conducted, published in JAMA Dermatology, it was found that only 43 % of the participants surveyed were able to understand the meaning of sun protection factor (SPF) and only 7 % knew how to find products with good protection against early skin aging.

The same group of people were further surveyed by showing to them the front and back portions of a common sunscreen with SPF 30 to evaluate their individual take on its labelling and usage. The study found that 38 and 23 % were able to recognize certain terminologies related to skin protection and the importance of sunscreen in protecting the skin against sunburn or any other type of skin cancer caused by UV radiation, respectively.

“We need to do a better job of educating people about sun protection and make it easier for them to understand labels,” lead author Dr. Roopal Kundu, an associate professor in dermatology at the Northwestern University Feinberg School of Medicine and a board-certified general medical dermatologist at the Northwestern Memorial Hospital, said in a news release.

When the skin is extremely exposed to ultraviolet blue (UV-B) rays, it burns. This skin response is termed as a “sunburn”. UV-B rays or exposure to it over a long period of time is the leading cause of sunburns and can largely contribute to premature aging and skin cancer as well as ultraviolet A (UV-A) rays.

As a form of support in highlighting the importance of protection against both UV-A and UV-B rays, the Food and Drug Administration (FDA) established new guidelines for sunscreen labeling in the year 2011, and these products are now called as “broad-spectrum protection” sunscreen.

“We recommend you buy a sunscreen lotion labeled ‘broad spectrum protection’—which helps to protect against both types of UV rays—with an SPF of 30 or higher that is also water resistant,” Dr. Kundu further stated in the release. “SPF 30 blocks 97 percent of the UVB radiation. But, you need to reapply it every two hours, using about a shot glass full of lotion over your exposed skin, for the best results.”

In the summer of 2014, the Northwestern researchers conducted a survey on 114 patients from their dermatology clinic. In this study, they found the top three factors that highly influenced consumers’ sunscreen buying practice, and these include (a) highest SPF value, (b) sensitive skin formulation, (c) and water and sweat resistance. Moreover, it was also found that preventing sunburn is the primary reason of the 75 % of participants in wearing sunscreen under the sun, while preventing skin cancer is what impels the almost 66 % of participants in using sunscreen. Also, 80 % of these patients stated they bought sunscreen in the previous year.

Since nearly half of this group of individuals was found to buy products with the highest SPF available, it is one major concern of the researchers to emphasize the huge importance of deciding and choosing the right SPF value.

“Just because you buy SPF 100 doesn’t mean you are 100 percent protected,” Kundu said. “Staying out of the sun is the only way to guarantee 100 percent protection.”

“If an individual applies SPF 30 sunscreen to the skin 15 minutes before going outdoors, he can then stay outside 30 minutes longer without getting a sunburn,” Kundu added.

In this study, researchers found that giving a label of “UV-A” rated with a star (out of four stars) and “UV-B” rated as an SPF value may contribute a solution for consumers to better understand the labelling of these products.


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