Quantity of sunscreen used by European students

Background The ability of sunscreen products to delay sun-induced skin eryt hema is indicated by the sun protection factor (SPF), which is measured usi ng an internationally agreed sunscreen thickness of 2 mg cm(-2). Objectives To determine the thickness of sunscreen used under practical con ditions. Methods In two double-blind randomized trials performed in five different p laces in Europe in 1997 and 1998, 148 18-24-year-old students received eith er an SPF 10 or an SPF 30 sunscreen to be used during their summer holidays , Results Complete. detailed data on quantities of sunscreen used and skin ar eas on to which sunscreen was applied were available for 124 students. The median thickness of sunscreen applied was 0.39 mg cm(-2). We found no varia tion in sunscreen thickness according to sex, skin phototype, study place o r SPF. Conclusions Our results indicate that most consumers do not benefit from th e SPF indicated on sunscreen bottles, and do not support the idea that thic kness of sunscreen applied would be greater if these products were cheaper. We suggest that information on ability of a sunscreen product to prevent s unburn should be adapted in order to reflect actual usage patterns.