Danish sunbathers’ application of sunscreen

This report describes Danish sunbathers’ application of sunscreen in 2016. We have investigated if the used amount of sunscreen was adequate to gain sufficient sun

The sun protection factor (SPF) labelled on sunscreen bottles is a measure of the protective efficacy of the sunscreen against sunburn. To gain the labelled SPF it requires that the sunscreen is applied in a thickness of 2 mg sunscreen per cm2 skin. A thinner layer of sunscreen lowers the protection significantly. Ninety-nine Danish adults were enrolled at Danish beaches between 10:30 AM and 15:15 PM from June through August 2016. Their sunscreen bottles were weighed before and after sunscreen application. Participants’ skin areas exposed to the sun were estimated from their height, weight and clothing. From the used amount of sunscreen, the label SPF on the bottle and the exposed body surface area the true SPF was calculated for each participant. The participants used sunscreen labelled as SPF 22 in average. They used an amount of sunscreen providing them an average true SPF of 2.7 (range: 1.2-13.1). The mean true SPF we have found in the present project is adequate to protect an average Dane against sunburn while sunbathing 3 hours on a Danish beach at midday. Prolonged exposure or skin lighter than average, requires a true SPF of more than 2.7.