Sun Protection Factor, commonly referred to as SPF, is a measure of how well a sunscreen can protect the skin from harmful ultraviolet (UV) rays. Specifically, it indicates how long it would take for the sun's UVB rays to redden the skin when using the product compared to the time without it. For instance, an SPF 30 sunscreen theoretically allows you to stay in the sun 30 times longer than without protection. However, SPF does not cover UVA rays, which also contribute to skin damage and aging.
