In Vivo Determination of sun protection factor (SPF)

ISO 24444: Cosmetics — Sun protection test methods — In vivo determination of sun protection factor (SPF)

The sun protection factor or SPF test, which uses the skin's erythemal response to ultraviolet (UV) radiation, estimates the level of sun protection provided by sunscreen products. SPF can be defined as a ratio calculated from the energies required to produce a minimal erythema response on the skin of human test subjects with and without sunscreen product.

ISO 24444 covers methods for the in vivo determination of sun protection factor (SPF) applied to products intended to come into contact with human skin, containing any ingredient that can absorb, reflect or scatter ultraviolet (UV) rays.

The product is applied to the human subject skin. The "Sun Simulation" test is performed by applying small gradual doses of light to the area where the product is applied, with a solar simulator. These tests are carried out to test the effectiveness of cosmetic products such as sunscreen.

"In vivo determination of sun protection factor (SPF)" can be performed safely in authorized laboratories.