Elta ® Tan Sunless Tanning Lotions reacts with the keratin (protein) in the upper layers of the skin to quickly produce a natural, healthy-looking tan for most skin tones. Not all Tanning Lotions are created equal. Elta Tan Sunless Tanning lotions works indoors in about 4 hours, without sun. Tans faster and with more natural color than other products, with no artificial dyes.