In vitro assessments of UVA protection by popular sunscreens available in the United States

Abstract

Background The importance of adequate ultraviolet A (UVA) protection has become apparent with improved understanding of the mechanism of UVA-induced damage to tissues. Currently in the United States, there is no regulation on testing and labeling of sunscreens for UVA protection. In August 2007, the Food and Drug Administration (FDA) addressed this issue in a proposed rule. Objectives We sought to assess in vitro the degree of UVA protection provided by 13 popular sunscreen products that are commercially available in the United States. Method Thirteen sunscreen products were purchased. UVA protection of each product was measured and assessed with 3 in vitro UVA labeling indices: (1) the FDA Proposed Amendment of Final Monograph, August 27, 2007; (2) European Commission Recommendation--the Colipa and critical wavelength methods; (3) and United Kingdom's Boots star rating system. Results Based on the new FDA-proposed guidelines, 8 products achieved the medium protection category, and 5 products achieved high protection. The latter 5 products also fulfilled the UVA protection based on the Colipa guideline desired by the European Commission Recommendation. Nine products achieved the desired critical wavelength value of 370 or higher. Based on the United Kingdom's Boots star rating system, 6 products achieved a rating of 3 stars, and the remaining 7 products achieved no star rating. Limitations The study only evaluated a small number of sunscreen products, and only in vitro methods were used to assess the degree of UVA protection. Conclusions The majority of the tested sunscreens in this study offered a medium degree of UVA protection. Compared with the sunscreens in the past, this study shows that UVA protection of sunscreens has improved. Sunscreens with avobenzone and octocrylene provided a higher degree of UVA protection. Globally, there is no uniform standard on testing and labeling sunscreens for UVA protection. In the United States, the FDA has just started to create a much-needed standard. This effort is necessary to educate the public better on how to choose products with adequate UVA protection.