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||The examples and perspective in this article deal primarily with the United States and do not represent a worldwide view of the subject. (August 2010)|
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 links were made by health authorities between exposure to the sun and other sun tanning methods, such as sunbeds or tanning beds, and the incidence of skin cancer.
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 natural, and unlike many sunless tanning products, are long-lasting. In addition, carotenoids have been linked to more attractive skin tone than suntan.[unreliable source?]
Carotenaemia (xanthaemia) is the presence in blood of the yellow pigment carotene from excessive intake of carrots or other vegetables containing the pigment resulting in increased serum carotenoids. It can lead to subsequent yellow-orange discoloration (xanthoderma or carotenoderma) and their subsequent deposition in the outermost layer of skin. Carotenemia and carotenoderma is in itself harmless, and does not require treatment. In primary carotenoderma, when the use of high quantities of carotene is discontinued the skin color will return to normal. It may take up to several months, however, for this to happen.
Lycopene is a key intermediate in the biosynthesis of beta-carotene and xanthophylls.
Due to its strong color and non-toxicity, lycopene is a useful food coloring (registered as E160d) and is approved for usage in the USA, Australia and New Zealand (registered as 160d) and the EU.
A sunless-tanning product is tanning pills which contain beta-carotene.
However, chronic, high doses of synthetic β-carotene supplements have been associated with increased rate of lung cancer among those who smoke.
Canthaxanthin is most commonly used as a color additive in certain foods. Although the FDA has approved the use of canthaxanthin in food, it does not approve its use as a tanning agent. When used as a color additive, only very small amounts of canthaxanthin are necessary. As a tanning agent, however, much larger quantities are used. After canthaxanthin is consumed, it is deposited throughout the body, including in the layer of fat below the skin, which turns an orange-brown color. These types of tanning pills have been linked to various side effects, including hepatitis and canthaxanthin retinopathy, a condition in which yellow deposits form in the retina of the eye. Other side effects including damage to the digestive system and skin surface have also been noted. The FDA withdrew approval for use of canthaxanthin as a tanning agent, and has issued warnings concerning its use.
Other products 
DHA-based products 
The most effective sunless tanning involves the use of lotions and sprays that contain dihydroxyacetone (DHA) as the active ingredient. DHA is not a dye, stain or paint, but causes a chemical reaction with the amino acids in the dead layer on the skin surface. This is similar to the Maillard reaction, a process well known to food chemists that causes the browning that occurs during food manufacturing and storage. It does not involve skin pigmentation nor does it require exposure to ultraviolet light to initiate the color change. The effect is temporary and fades gradually over 3 to 10 days.
These products are available as gels, lotions, mousses, sprays and wipes, some of which also use erythrulose which works identically to DHA, but develops more slowly. Both DHA and erythrulose have been known to cause contact dermatitis.
Professional spraytan applications are available from spas, salons and gymnasiums by both hand-held sprayers and in the form of sunless or UV-Free spray booths. The enclosed booth, which resembles an enclosed shower stall, sprays the tanning solution over the entire body. The U.S. Food and Drug Administration (FDA) states when using DHA-containing products as an all-over spray or mist in a commercial spray "tanning" booth, it may be difficult to avoid exposure in a manner for which DHA is not approved, including the area of the eyes, lips, or mucous membrane, or even internally. DHA is not approved by the FDA for inhalation.
September 2012 also saw a surge in debate within the United Kingdom regarding the inhalation of DHA through spray tanning. While the quantities inhaled would have to be considerably higher than an average consumer or even spray tan technician would be exposed to, press coverage on the issue has resulted in increased consumer diligence with regard to the level of DHA and other ingredients in their spray tanning products, and a move toward more naturally-derived spray tan solutions. An EU Directive published by the Scientific Committee of Consumer Safety to eventually limit DHA content of spray tan products to 14% has also been cited within this discussion.
DHA has been approved for cosmetic use by the FDA. The European Commission has issued an extensive 2010 Opinion on DHA in which they concluded spray tanning was safe for consumers, but recommended DHA content be limited to 14%. Because DHA does not use the skin's melanocytes to make the skin a tan color, it is recommended as a cosmetic disguising cover for vitiligo patients.
Tyrosine-based products 
Although gels, lotions or sprays that contain DHA are said to be the most reliable and useful, there are other types of products on the market. Tanning accelerators—lotions or pills that usually contain the amino acid tyrosine—claim that they stimulate and increase melanin formation, thereby accelerating the tanning process. These are used in conjunction with UV exposure. At this time, there is no scientific data available to support these claims.
Melanotan hormone 
Afamelanotide, a synthetic melanocyte-stimulating hormone analog, which induces melanogenesis through activation of the melanocortin 1 receptor, is another alternative on the horizon. A 1991 clinical Investigational new drug trial conducted at the Department of Internal Medicine, University of Arizona Health Sciences Center with afamelanotide (then known by its amino acid formula [Nle4, D-Phe7] (NDP)-alpha-melanocyte-stimulating hormone) with 28, "healthy white men" who used a, "high-potency sunscreen during the trial" and concluded, "Human skin darkens as a response to a synthetic melanotropin given by subcutaneous injection. Skin tanning appears possible without potentially harmful exposure to ultraviolet radiation." 
Afamelanotide in a subcutaneous implant form is currently undergoing clinical trials and being developed by a company in Australia.
Temporary bronzers 
Bronzers are a temporary sunless tanning or bronzing option. These come in powders, sprays, mousse, gels, lotions and moisturizers. Once applied, they create a tan that can easily be removed with soap and water. Like make-up, these products tint or stain a person's skin only until they are washed off.
They are often used for "one-day" only tans, or to complement a DHA-based sunless tan. Many formulations are available, and some have limited sweat or light water resistance. If applied under clothing, or where fabric and skin edges meet, most will create some light but visible rub-off. Dark clothing prevents the rub-off from being noticeable. While these products are much safer than tanning beds, the color produced can sometimes look orangey and splotchy if applied incorrectly.
A recent trend is that of lotions or moisturizers containing a gradual tanning agent. A slight increase in color is usually observable after the first use, but color will continue to darken the more the product is used.
Air brush tanning is a spray on tan performed by a professional. An air brush tan can last five to ten days and will fade when the skin is washed. It is used for special occasions or to get a quick dark tan. At-home airbrush tanning kits and aerosol mists are also available.
Since the tanning ingredients which color the skin do not provide any protection against ultraviolet rays when the person is outdoors, to offer protection against UV rays products usually contain a sunscreening agent. The ingredients known to offer appropriate protection are titanium dioxide, zinc oxide, or avobenzone. There has also been some research to suggest that DHA can make the skin temporarily more susceptible to sun damage.[medical citation needed]
Risks of inhaling or ingesting DHA are not known. People are advised to close their eyes or protect them with goggles and to hold their breath or wear nose plugs while they have a spray-on tanning applied.
September 2012 saw a surge in debate within the United Kingdom regarding the inhalation of DHA through spray tanning. While the quantities inhaled would have to be considerably higher than an average consumer or even spray tan technician would be exposed to, press coverage on the issue has resulted in increased consumer diligence with regard to the level of DHA and other ingredients in their spray tanning products, and a move toward more naturally-derived spray tan solutions. An EU Directive published by the Scientific Committee of Consumer Safety to eventually limit DHA content of spray tan products to 14% has also been cited within this discussion.
The European Commission Scientific Committee on Consumer Safety has issued a comprehensive 2010 Opinion on DHA in which the committee concluded that DHA and spray tanning did not pose risk to the consumer.
Many self tanners use chemical fragrances which may cause skin allergies or may trigger asthma. Furthermore, some of them contain parabens. Parabens are preservatives that can affect the endocrine system.
Tanners can stain clothes. It is therefore important to look for fast drying formulas and wait around 10 to 15 minutes for the product to dry before dressing.
After self-tanner is applied, the skin may be especially susceptible to free-radical damage from sunlight, according to a 2007 study led by Katinka Jung of the Gematria Test Lab in Berlin. Forty minutes after the researchers treated skin samples with 20% DHA they found that more than 180 percent additional free radicals formed during sun exposure compared with untreated skin.
The FDA released a report that DHA is absorbed into deeper layers of skin and may be less safe than previously thought. However, any absorption into the living areas of the skin could be pose a potential risk, even if none of it made it into the bloodstream, said Dr. Darrell Rigel, an NYU professor of dermatology. The fact that some does potentially get into the bloodstream raised additional red flags for him that he said needed to be further explored. Rigel was especially concerned for repeated users of the product and those in hig "What you showed me certainly leads me to say I have to rethink what I'm doing and what I'm saying because there's ... a real potential problem there," he said. "I feel that I must give my patients the information that you've given to me, because I think it is valid." Before he read all of the papers, Rigel said, he would "tell my patients what every other dermatologist tells them: 'If you want to be tanned, [tanning with DHA] is effective, it's not being absorbed and there's no long-term problems.' After reading these papers, I'm not sure that's true anymore."
See also 
- Ross AC, Taylor CL, Yaktine AL, et al., ed. (2011). "8. Implications and Special Concerns". Dietary Reference Intakes for Calcium and Vitamin D: Institute of Medicine (US) Committee to Review Dietary Reference Intakes for Vitamin D and Calcium. Washington, DC: National Academies Press (US).
- "Carotenoids linked to attractive skin tone". psypost.org. January 11, 2011.
- Di Mascio (1989) pp. 532–538
- 21 CFR 73.585
- Australia New Zealand Food Standards Code"Standard 1.2.4 - Labelling of ingredients". Retrieved 2011-10-27.
- UK Food Standards Agency: "Current EU approved additives and their E Numbers". Retrieved 2011-10-27.
- Tanvetyanon T, Bepler G (July 2008). "Beta-carotene in multivitamins and the possible risk of lung cancer among smokers versus former smokers: a meta-analysis and evaluation of national brands". Cancer 113 (1): 150–7. doi:10.1002/cncr.23527. PMID 18429004.
- US FDA/CFSAN - Tanning Pills
- Lloyd, Roger V; Fong, Anna J; Sayre, Robert M (2001). "In Vivo Formation of Maillard Reaction Free Radicals in Mouse Skin". Journal of Investigative Dermatology 117 (3): 740–2. doi:10.1046/j.0022-202x.2001.01448.x. PMID 11564185.
- FDA Comments on Sunless Tanners and Bronzers
- http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=73.1150 Code of Federal Regulations, Title 21, Volume 1, §73.1150 Listing of color additives exempt from certification
- Levine, Norman (1991). "Induction of Skin Tanning by Subcutaneous Administration of a Potent Synthetic Melanotropin". JAMA: the Journal of the American Medical Association 266 (19): 2730. doi:10.1001/jama.1991.03470190078033.
- "WebMd.com - Choosing the Best Sunscreen". Retrieved 2010-07-05.
- "Choose a Natural Self-tanner". Retrieved 2010-07-05.
- K Jung, M Seifert, Th Herrling, J Fuchs "UV-generated free radicals (FR) in skin: Their prevention by sunscreens and their induction by self-tanning agents." Spectrochim Acta A Mol Biomol Spectrosc. 2008 May;69(5):1423-8. Epub 2007 Oct 10.