Sunless tanning
Sunless tanning, also known as UV-free tanning, self tanning, spray tanning (when applied topically), or fake tanning, refers to the application of chemicals to the skin to produce an effect similar in appearance to a suntan. The popularity of sunless tanning has risen since the 1960s after health authorities confirmed links between UV exposure (from sunlight or tanning beds) and the incidence of skin cancer.
Carotenoids
Artificial sunscreen absorbs ultraviolet light and prevents it from reaching the skin. It has been reported that sunscreen with a sun protection factor (SPF) of 8 based on the UVB spectrum can decrease vitamin D synthetic capacity by 95 percent, whereas sunscreen with an SPF of 15 can reduce synthetic capacity by 98 percent.
A safe and effective method of sunless tanning is consumption of certain carotenoids — antioxidants found in some fruits and vegetables such as carrots and tomatoes — which can result in changes to skin color when ingested chronically and/or in high amounts. Carotenoids are long-lasting. In addition, carotenoids have been linked to more attractive skin tone than suntan. Carotenes also fulfil the function of melanin in absorbing the UV radiation and protecting the skin. For example, they are concentrated in the macula of the eye to protect the retina from damage. They are used in plants both to protect chlorophyll from light damage and harvest light directly.