What is suntanning?

Suntanning is the body's natural protection against the harmful effects of UVB - namely sunburn and related disorders - and is brought about by exposure of the skin to the longer wavelength ultraviolet light (UVA) which causes the Melanin or pigmentation in the skin to migrate to the surface layers where it oxidises to form a brown coloured protective layer. This layer acts as a barrier which reduces the penetration of UVB.

A very small amount of UVB must be present before UVA can produce the tanning reaction in the skin.