An in vivo study to evaluate the influence of oil blotting paper on the efficacy of sunscreen.

Abstract

Ultraviolet radiation (UVR) is a major cause of photoaging and photocarcinogenesis. An appropriate application of sunscreen can effectively protect UV damage but cause unpleasant skin oiliness. Oil blotting paper is commonly used to reduce oiliness in some parts of the world although its influence on the efficacy of sunscreen has not been carefully investigated. To evaluate the efficacy of sunscreen after applying oil blotting paper. Measurement of oiliness and sunscreen efficacy was compared before and after the use of oil blotting paper in 11 healthy volunteers, 10 females, and 1 male. Specifically, 3 zones on each subject's back were exposed to UVR from a solar simulator, that is, 1) no sunscreen, 2) sunscreen (organic sunscreen at 2mg/cm2 SPF 30) left on for 30minutes, and 3) sunscreen left on for 30minutes followed by application of oil blotting paper. Skin oiliness was also compared before and after oil blotting using a sebumeter. All areas were phototested for the comparison of the minimal erythema dose (MED) and sun protection factor (SPF). The averaged MED of our subjects is 4.3 standard erythema doses (SED) in the unprotected area. The averaged MED was decreased after oil blotting from 89.8 SED to 59.8 SED. The SPF was also decreased from 20.70 to 13.99. Application of oil blotting paper significantly reduces the efficacy of organic sunscreen.