In vitro Very Water Resistance

The in vitro Very Water Resistance (VWR) of sunscreens was tested by applying the same principle as in vivo, which determines the percentage of retention of sunscreen products by assessing the Sun Protection Factor (SPF) before and after double water immersions. Based on a publication, this in vitro method for Very Water Resistance percentage assessment is a practical, convenient and relevant tool in terms of reproduciblity and correlation with in vivo values.