sun protection factor
Last reviewed 01/2018
- the Sun protection factor (SPF) is a method of categorising the protection against ultraviolet B wavelength sunlight (UVB)
- the SPF provides an estimate of the efficiciency in blocking UVB sunlight; the SPF number of a sunscreen indicates the incremental protection offered by the specific preparation; thus a sunscreen with a SPF of 10 theoretically means that person using this preparation may remain in sunlight 10 times longer without burning