Which SPF test method to use?

Over the past two years, I have described the SPF test method and its alternatives several times. In my last column, “Two additions to the SPF toolbox!” in January 2025, two new alternative methods were presented [1-3]. Particularly in Europe, I am seeing some confusion about what exactly this means. The framework for SPF testing is currently uncertain. There is pressure to use the new in vitro/non-invasive methods. Various factors need to be weighed up…