Most sunscreens are designed to work for about 2 hours. However, this can vary depending on factors such as the SPF, the degree of perspiration, the water resistance of the product, and the amount of sunscreen used. To ensure you're optimally protected, it's important to read the instructions on the product.
Moreover, you mustn't forget that you should apply sunscreen regularly, even if the sun isn't shining. UV radiation can still damage the skin, even when it's cloudy. Using sunscreen is therefore an important way to protect the skin against this damage. It is recommended to reapply sunscreen at least every two hours. Also, reapply the sun protection after swimming, intense sweating or after drying off with a towel.
Looking for a good routine? Read here how to make the most of your sun protection
