Performance Metrics of Sunscreen Formulations: In Vitro and In Vivo Techniques.

Effective skin protection of consumers by sunscreens can only be achieved when meaningful and reliable test methods are available to objectively measure the protection of sunscreen products. Quantitative, scientifically sound, and valid methods to detect UVB and UVA light protection as well as methods to assess sunscreen substantivity to water are required. Continuous improvement and, if necessary, extension of the test methods are important to provide optimum protection from harmful sun rays to the consumer. This work documents the historical background of the development of sunscreen test methods and provides the actual worldwide status of applied methods. Future developments and trends are discussed as far as they actually become apparent.