Comparison of ultraviolet A light protection standards in the United States and European Union through in vitro measurements of commercially available sunscreens

Background The importance of adequate ultraviolet A light (UVA) protection has become apparent in recent years. The United States and Europe have different standards for assessing UVA protection in sunscreen products. Objective We sought to measure the in vitro critical wavelength (CW) and UVA protection factor (PF) of commercially available US sunscreen products and see if they meet standards set by the United States and the European Union. Methods Twenty sunscreen products with sun protection factors ranging from 15 to 100+ were analyzed. Two in vitro UVA protection tests were conducted in accordance with the 2011 US Food and Drug Administration final rule and the 2012 International Organization for Standardization method for sunscreen effectiveness testing. Results The CW of the tested sunscreens ranged from 367 to 382 nm, and the UVA PF of the products ranged from 6.1 to 32. Nineteen of 20 sunscreens (95%) met the US requirement of CW >370 nm. Eleven of 20 sunscreens (55%) met the EU desired ratio of UVA PF/SPF > 1:3. Limitations The study only evaluated a small number of sunscreen products. Conclusion The majority of tested sunscreens offered adequate UVA protection according to US Food and Drug Administration guidelines for broad-spectrum status, but almost half of the sunscreens tested did not pass standards set in the European Union.