Sun protection factor (SPF)

The sun pro­tec­tion fac­tor (SPF) indi­ca­tes how well a sun­screen pro­tects against UVB radia­ti­on. In theo­ry, it descri­bes how much lon­ger skin can be expo­sed to the sun befo­re red­de­ning, com­pared with unpro­tec­ted skin. UVB rays are the main cau­se of sunburn.

Appli­ca­ti­on

For ever­y­day use, at least SPF 30 is gene­ral­ly recom­men­ded, and SPF 50 in strong sun, at alti­tu­de, for fair skin or after aes­the­tic tre­at­ments. Pro­tec­tion against UVA is equal­ly important, as it pene­tra­tes deeper and con­tri­bu­tes signi­fi­cant­ly to pho­to­ag­e­ing and pig­men­ta­ti­on; in Euro­pe this is shown by the UVA logo in a cir­cle. Con­sis­tent sun pro­tec­tion also lowers the risk of skin cancer.

Good to know

The sta­ted value is mea­su­red in the labo­ra­to­ry with a thick lay­er; in ever­y­day life, most peo­p­le app­ly far less. App­ly gene­rous­ly and reap­p­ly after swea­ting, swim­ming or towel­ling off. Reap­p­ly­ing does not extend the pro­tec­tion time, it only main­ta­ins it. The appro­pria­te fac­tor also depends on the Fitz­pa­trick skin type.

Matching tre­at­ment at Swiss Der­ma Cli­nic: Light dama­ge to the skin