Determination of SPF in vivo

Determination of SPF in vivo

In Europe sunscreens are classified and regulated as cosmetics and their efficacy is evaluated under standardized condition in accordance with the International Standard ISO 24444:2019 Cosmetics –Sun protection test methods –In vivo determination of the sun protection factor (SPF) test method.

SPF is determined by the ratio of UV energy required to produce a minimal erythemal dose (MED) in protected skin (standardized application thickness of 2 mg/cm2) to unprotected skin and is a measure for the UVB-protection effectiveness of a sunscreen.