How does it work containing mexoryl sx an advanced patented filter this formula hydrates the skin and protects it against uvb rays which cause sun burn and uva rays which can lead to long term skin damage 1apply generously all over the body and face before going in the sun the ears back of the neck and calves are particularly vulnerable to sunburn scars and moles must be given extra protection 2 reapply frequently it is best to reapply every 2 hours dont go in the