The sun protection factor, or SPF, measures the amount of protection a cream offers from ultraviolet B radiation (UVB), the kind of rays that cause burns. The higher the SPF, the higher the protection. Your sunscreen also needs to protect you from ultraviolet A (UVA), rays which are associated with skin ageing. If the sunscreen packaging says “broad spectrum,” that means the cream shields you from both UVA and UVB. You may also see ‘PA’ followed by plus signs on the label — this shows the level of UVA protection a cream has. The more plus signs you see, the higher the product’s UVA protection. The NHS recommends applying SPF 30 or higher 30 minutes before going out so it has time to be absorbed.