Sunscreen may not be giving as much UV protection as commonly believed, according to recent research. In their experiment published in Acta Dermato-Venereology, researchers from King’s College London analyzed DNA damage after decreasing sunscreen application below the 2mg/cm2 thickness recommended. They did so to mimic common application of sunscreen, being that most do not achieve the thickness recommended to achieve full SPF protection. They found that SPF 50 sunscreen applied in this manner yields at most 40% of the protection expected.
The study incorporated 16 fair-skinned patients with their exposed a small segment of their skin to UV radiation to simulate sunlight. Sunscreen was applied to their skin at several thicknesses, varying from 0.75 mg/cm2 to replicate typical thickness to the recommended 2mg/cm2 thickness. Some participants were exposed to five days of varying UV intensities to model vacation conditions.
Performing skin biopsies after exposure, researchers found that there was a considerable amount of DNA damage in the unprotected skin, despite the low, non-sunburn inducing UV intensity used. The team noted that unprotected skin displayed more DNA damage done in one day from low dose UV radiation than the skin protected with recommended thickness showed after five days of intense radiation.
From these findings, the King’s College team suggests that people use a higher SPF than they believe is appropriate to achieve desired protection. Nina Goad of the British Association of Dermatologists notes that sunscreen alone should not be our only line of defense from skin damage, stressing the importance of clothing and shade in UV protection. Acknowledging the lack of public education on UV protection, the researchers claim that their findings “demonstrate that public health messages must stress better sunscreen application to get maximal benefit.”
— Newsweek (@Newsweek) July 26, 2018