The sun emits two types of ultraviolet (UV) light rays, which are called UVA and UVB. Indoor tanning equipment uses powerful lamps to reproduce this UV light with a mix of UVA and UVB rays.
UVA are mainly browning rays that turn your skin’s melanin from pink to brown. This is your body’s natural protection from the sun. UVA rays penetrate deeper into the skin than UVB, are less harmful and take a few hours to produce their full results.
UVB rays stimulate your skin’s melanocyte cells, which in turn bring more melanin to the surface. These rays penetrate the skin less deeply, add a natural sheen to your skin and take slightly less time to show their full effect.