Beyond SPF: getting the tan back

In Australia, Cancer Councils and other professionals emphasise this through catchphrases such as: ‘There is no such thing as a safe tan’.1 Additionally, tanning beds are soon to be banned2 – probably for both professional and private use. SPF and UVA protection categories have also recently been substantially increased,3 meaning higher efficacy in terms of sun damage protection. Chemical skin tanning is also a recognised treatment for some medical conditions.4,5 Observation of the retail and the online marketplaces for sun products has indicated a lift in the number of shelf facing allocate to self tanning products.6 Simultaneously, professional providers of commercial solariums have moved to spray booths in order to stay in business. Thus, there is a corresponding increase in spray-based formulations. A tanned skin gives, in the least, a more even appearance in skin colour. This has been shown to be associated with attraction based on appearance.7 As it becomes more difficult to achieve this tan by other, unsafe means, it is likely that growth in the use of chemical-based reactant tanning will continue to increase.

What works and why

The most widely used and well established chemical tanners are dihydroxyacetone (DHA) and eryrthrulose (ERY). Both of these are simple sugars. Other actives, not covered in this discussion are synthetic and natural skin dyes. These do not generally chemically react, but simply stain the skin. Most commonly, formulations incorporate more than one active in order to achieve a more natural looking tan. The Maillard reaction is well known and widely occurring in food processing and this is the basis of the brown colour of the chemical tan. The colours produced by each amino acid:sugar combination are highly variable. In order to demonstrate this, we prepared five amino acid: dihydroxyacetone combinations and measured the degree of brownness according to the Hazen colour scale. These are shown in Table 2.