At the end of 2024 two alternative SPF methods have been published, ISO 23675:2024 an in vitro method and ISO 23698:2024 a non-invasive in vivo/in vitro hybrid method [1,2]. Over the years, I have often written about these methods. Just last year the two columns appeared “Two additions to the SPF toolbox!” and “Which SPF-Testing Method to use?” [3-6].
Just recently, in September 2025, the scientific and statistical basis was published in a supplement to the International Journal of Cosmetic Science (IJCS) entitled “Are there alternatives to the traditional in-vivo SPF test (ISO 24444)? Comparison and statistical analysis of 5 proposed methods” [7-13]…