The Modern Bronze Age: Fake Tan
By Aastha Shreeharsh
“Sun-kissed skin”, “radiant”, “bronze”, and a “healthy glow” – these are just a few of the many descriptors trending on social media and in the beauty industry worldwide, especially in Western countries. While this look could possibly be achieved by a few sun-drenched days at the beach, many people are now opting for sunless alternatives to tanning.
Q: That seems recent – so what’s up with the title?
While it is true that the original Bronze Age lasted for many centuries and fake tanning is a relatively recent phenomenon, the “Modern Bronze Age” is just a term used by popular media to describe the era of the fake-tan – playing on the word “bronze” to describe the generally desired outcome of a fake tan. From celebrities to the former US president Donald Trump (footnote 1) [1], it seems that sunless tanning products, such as tanning beds, lotions, and sprays, are in extensive use. Many people from countries where a sunny day is a rarity turn to fake tanning as a solution, and they have the scientist Eva Wittgenstein to thank for her discovery.
Q: How did one stumble upon a fake tan?
As with many scientific discoveries, one did not set out to find or develop a fake tan. While investigating the oral application of a chemical compound known as DHA (dihydroxyacetone; not to confuse with the omega-3 fatty acid (docosahexaenoic acid) in fish oil) for children with glycogen defects, she observed the noticeable coloration of skin where the DHA spilled. This was not the first time this skin-browning effect was noticed by scientists – German scientists in the 1920s had already done so – but it was the first time for DHA to be considered for cosmetic purposes [2]. Wittgenstein researched this further and published a paper in 1960 to explain how DHA produced an “artificial tan” [3].
Q: Wow! So, you’re telling me, I can just use a lotion at home and get a tan without having to suffer outside during the summer. How does that work? Could it also offer me sun protection?
This may come as a surprise, but this process of skin-browning follows the same reaction responsible for the browning of bread and roast meat, known as the Maillard reaction. Our skin is composed of a few layers, and the outer surface comprises a layer of dead skin cells. The Maillard reaction between the amino acids in this outer layer and the colorless DHA produces the brown pigment melanoidins [2].
Nevertheless, the process is not instantaneous. After two to three hours, the skin begins to acquire a tan and the reaction carries on for another one to three days [2, 4]. Once formed, melanoidins can't be washed off by water, soap, or moisturizer until the skin cells are shed. [2, 4]. The browning effect can last for one week [2, 4].
However, unlike the pigment melanin in natural tanning, melanoidins don’t offer much ultraviolet (UV) protection on their own (Figure 1). It’s estimated that most of these sunless tanners can offer only a meager SPF of 3, which is not nearly enough sun protection [2]. Therefore, it’s extremely important to wear sunscreen with adequate SPF when going outdoors, with or without a sunless tan.
![](/sites/sciencefocus.prod01.ust.hk/files/sciencefocus/article/Issue%20027/Fake%20Tan/Figure%20(Aastha)_Dan_AI_English.png)
Figure 1 Chemical structures of the three major types of melanoidin resulted from the Maillard reaction between DHA and assorted amino acids (top) [5], and the stoichiometric structure of melanin (bottom). The highly conjugated π-bonding (alternating single and double bonds) ring system of melanin enables the molecule to absorb UV effectively.
Q: That story does not fill me with a whole lot of confidence about fake tanning, and the cosmetic industry has a history of being misleading to sell us products. What do scientists have to say about its safety?
Perhaps the idea that the same reaction governing the fake tanning process also takes place during the roasting of meat may have been a bit off-putting. According to scientists, there is no significant cause for concern – with some caveats. One study from 2008 suggested that our skin may become more susceptible to UV radiation after the application of tanning products, as a UV exposure after the application of 20% DHA solution on porcine skin resulted in the formation of 180% more harmful free radicals, which are generally believed to cause premature skin aging and wrinkling [6]. Fortunately, most over-the-counter tanning lotions contain only 3-5% of DHA, and precautions can always be taken by using sunscreen and avoiding the sun after applying a self-tanner [2]. Another point to note is that, the US Food and Drug Administration (FDA) has approved DHA only for external application, meaning that a self-tanning lotion may be a safer choice than a spray because DHA is not likely inhaled or ingested into the body [7]. Overall, self-tanning is considered as a safer alternative to tanning naturally.
Q: Awesome! Can I give my pet a spray tan?
Okay, it’s unlikely many readers were thinking about this, but apparently, someone was. In 2008, one study found that using 5% DHA on Mexican hairless dogs can result in severe contact dermatitis, causing blisters and epidermal necrosis [8]. So, if you love your pet, it’s possibly best to forego the spray tan! (An obvious but necessary disclaimer on animal cruelty: It’s not a good idea to use this on animals you do not love either.)
Q: Well, that’s a bit scary. Can it hurt us humans?
Apart from the caveats above, with any cosmetic product, there is a chance it does not react well to your skin – which is why you should always test a product on a small patch of skin.
In another way, the whole concept of fake tanning may have hurt us. Historically, “sun-kissed” skin was associated with labor in the scorching heat – not considered very attractive. The idea that a tan is undesirable is one that is still bandied about in many Asian households, but amongst countries with colder climes, tans came to be associated with luxury as it meant you could afford to enjoy more tropical vacation spots [9]. The invention of the fake tan has perhaps made unattainable, short-lived beauty standards and trends more attainable for some; or, perhaps, it helps instead of hurts in some regions – making darker, tanner skin more the norm as we see those with fairer complexions seek tanner complexions that were once frowned upon.
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1 Trump has been the star of frenzied media coverage for many reasons aside from his distinct appearance and mannerisms; in this context, it is referring to his vibrant, orange complexion. He claims that accusations of him using fake tanning products are fake news, yet there is much debate surrounding the validity of such claims [1].
References
[1] Rogers, K. (2019, February 2). In the Pale of Winter, Trump’s Tan Remains a State Secret. The New York Times. https://www.nytimes.com/2019/02/02/us/politics/trump-tan.html
[2] Brunning, A. (2014, August 7). How Do Tanning Lotions Work? – The Chemistry of Fake Tan. Compound Interest. https://www.compoundchem.com/2014/08/07/faketan/
[3] Wittgenstein, E., & Berry, H. K. (1960). Staining of skin with dihydroxyacetone. Science, 132(3431), 894–895. https://doi.org/10.1126/science.132.3431.894
[4] Wong, M. (2015, November 3). The Science of How Fake Tan Works. Lab Muffin Beauty Science. https://labmuffin.com/the-science-of-how-fake-tan-works/
[5] Sun, Y., Zhang, P., Wang, X., Al-Zahrani, F. A. M., de Leeuw, N. H., & Lin, L. (2022). Deciphering key coloured compounds from sunless tanning reactions. Dyes and Pigments, 204, 110448. https://doi.org/10.1016/j.dyepig.2022.110448
[6] Jung, K., Seifert, M., Herrling, Th., & Fuchs, J. (2008). UV-generated free radicals (FR) in skin: Their prevention by sunscreens and their induction by self-tanning agents. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 69(5), 1423–1428. https://doi.org/10.1016/j.saa.2007.09.029
[7] U.S. Food and Drug Administration. (2022, March 15). Sunless Tanners & Bronzers. https://www.fda.gov/cosmetics/cosmetic-products/sunless-tanners-bronzers
[8] Kimura, T. (2008). Contact dermatitis caused by sunless tanning treatment with dihydroxyacetone in hairless descendants of Mexican hairless dogs. Environmental Toxicology, 24(5), 506–512. https://doi.org/10.1002/tox.20456
[9] Edwards, A. (2017, March 23). The Bronze Age: Shedding light (and throwing shade) on our tanning infatuation. Vox Magazine. https://www.voxmagazine.com/news/features/the-bronze-age-shedding-light-and-throwing-shade-on-our-tanning-infatuation/article_db0b63f0-04b2-53a1-8878-5d85c62402ca.html