Since the discovery of skin cancer in the 1960s, a wide range of ultraviolet(UV)-free tanning options have been manufactured. The sun's UV rays have been determined to be a major cause of skin cancer, but the desire for a pronounced tan has remained strong. As a consequence, many sunless tanning techniques have been explored, including the tanning bed that, in a sense, replicates the sun's UV rays. Sunless tanning products, including tanning lotions, bronzers, and sprays, are alternatives to direct sunlight, with dihydroxyacetone(DHA)-based products topping the list.
A common alternative to direct sunlight and the harmful UV rays of tanning beds, DHA-based products have generally proven the most effective UV-free tanning options. DHA is often applied to the skin in creams, lotions, and sprays, and can be applied at home without professional assistance. Instead of dying the skin or changing the skin's pigmentation, the application of DHA produces a chemical reaction between the amino acids contained within the dead, outer layer of skin cells. Tanning lotions and sprays that contain DHA are generally effective for anywhere from three days to two weeks and will begin to fade as the dead skin is rubbed off and replaced by a new layer.
Professional spray tans are also a conventional method of receiving DHA UV-free tanning. Sunless tanning salons specialize in these types of tans that are often administered while the customer is standing up. As a result, these professional, stand-up tans are more effective at covering the entire body and distributing the tan more evenly than one can accomplish at home. Nonetheless, spray tans are often met with caution by the Food and Drug Administration (FDA) since, if applied without the proper equipment and without the proper space, they can bring the DHA into contact with unadvised parts of the body, such as the eyes and other mucus membranes. The FDA does, however, approve DHA-based products for home and professional use, provided the tanning salon meets specific requirements.
There are several UV-free tanning options that are not DHA-based. Tyrosine-based gels and sprays are also produced, but they have not been scientifically validated. Tanning pills are also manufactured, usually containing tyrosine or canthaxanthin, but lack FDA approval. Many manufacturers and UV-free tanning salons additionally offer temporary bronzers, which are DHA-free and provide a short-term dye of the skin that can easily be washed away. Like DHA-based products, bronzers can be applied either professionally with an airbrush-like spray or at home with lotions, gels, or creams.