Several brands are competing in the development of creams with everincreasing SPF, and we can see products on the market with SPF 70, 90, and even 100! Many wonder whether such high protection is necessary, and if it could even be detrimental. Properly applied sunscreen with SPF 50 should block 98% of UVB rays, and when doubling the SPF to 100, the protection from UVB rays only raises to 99%.10 UVB radiation is the main cause of sunburn, but UVA penetrates deeper into the dermis and is more difficult to block. Exposure to both UVA and UVB causes the formation of harmful free radicals in the skin and is associated with a greater risk of developing cancer. It is therefore not only important to look for products with a high SPF, but also to look at the degree of UVA protection a product provides. In the EU, products must have a UVA / UVB protection ratio of at least 1/3. Most sun care products emphasise the importance of frequent application, but ‘once-a-day’ products have become very popular and are the source of some controversy. Anti-cancer organisations are concerned that such products can give a false sense of security that puts consumers at greater risk of sunburn. The submission of such declarations on the label is prohibited in Australia, a country with some of the strictest regulations regarding sun protection.15, 16 


source from https://www.personalcaremagazine.com