Sunscreen: Not As Protective As Was thought?4 years, 8 months ago
Posted on Jul 24, 2018, 9 p.m.
According to researchers from King’s College sunscreen users receive less than half of the sun protection than they think, use of higher SPF is required to block the cancer causing rays, as published in the journal Acta Dermato-Venereology.
It is known that most people don’t receive full ultraviolet radiation blocking benefit from sunscreen as they don’t use enough. Just how much sun protection people receive was assessed in this first of its kind experiment investigating DNA damage in the skin after lowering sunscreen thickness under 2mg/cm2 manufacturers SPF thickness rating.
Findings showed with a SPF50 applied typically at best it provided 40% of expected protection, prompting researchers to suggest that a higher SPF sunscreen should be used than thought necessary to ensure proper protection.
A chort of 16 fair skinned participants were divided into 2 groups of 3 women and 5 men each, with one groups receiving a single UVR exposure to simulate sunlight to area treated with SPF sunscreen of varied thickness ranging from 0.75mg - 2mg/cm2; and the other group receiving exposure of 5 consecutive days to mimic holiday exposure with UVR exposure varying throughout the experiment to replicate various holiday conditions and destinations.
UVR exposed area biopsies showed that the group repeatedly exposed to UVR considerable DNA damage was found on areas with no sun protection even with low UVR dose. Damage was decreased when sunscreen was applied at 0.75mg.cm2 and decreased even more at 2mg/cm2 even with higher URV doses. 5 days of exposure to high UVR with sunscreen at 2mg/cm2 showed much less damage than one day of low UVR dose exposure without sunscreen across all samplings.
Researchers concluded that given most people don’t wear sunscreen in the amount tested by the manufacturers it would be best to use a higher SPF than they think required; and that sunscreen alone should not be relied on, protection should include shade and clothing.
Materials provided by King's College London.
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A Young, J Greenaway, G Harrison, K Lawrence, R Sarkany, T Douki, F Boyer, G Josse, E Questel, C Monteil, A Rossi. Sub-optimal Application of a High SPF Sunscreen Prevents Epidermal DNA Damage in Vivo. Acta Dermato Venereologica, 2018; 0 DOI: 10.2340/00015555-2992