A self -tanning product is a cosmetic capable of simulate tanning, without exposure to sunlight. These are marketed in the form of creams, lotions or sprayand represent a valid alternative for those who do not want to give up the summer tan However, limiting the damage of UV rays, both natural and artificial (such as those of the so -called “lamps”). Typically they are applied to the unbalanced skin and give an effect that lasts for a few days. The most used active ingredient is the dihydroxiacetonewhich reacts with the amino acids of the corneous layer of the skin through a reaction similar to Maillard reaction (the same that scruptes foods such as bread or biscuits during cooking, so to speak), generating brownish pigments called melanoidine. However, it is a coloring temporary And it vanishes with the natural cell turnover. It is important to remember that these products do not stimulate melanin production And therefore they do not offer any protection from sunlight. For this reason, it is essential to use a protection During exposure to the sun and not confuse self -tanning with sunscreen.
What self -tanks contain and how they make us tan
Almost all self -tanning on the market have as their active ingredient the dihydroxiacetone (Dha), a compound particularly reactivebecause it contains a coal group (-c = O) and two obshydrile groups (–OH). This molecule, once applied on the skin, is absorbed by the corneous layer, the outer level of the epidermis, where it comes into contact with some biomolecules, mainly amino acids Free and proteins.
In most cases, the reaction takes place with the amino acids in the keratinthrough a chemical reaction similar to “Maillard reaction“ melanidineable to give the skin a darker coloring.
Although the DHA is the most used compound, there are other active ingredients with similar effects. One of the main is theerythrulosea sugary derivative capable of performing the same reaction at the level of the corneous layer, for this reason many products associate it with the DHA.
The effect of this reaction is visible already after an hour, even if you get the More evident result after 8-24h. When applying the cream, however you could already see a different coloring of the skin: some products in fact contain temporary dyes (which have no reaction with the skin) to make us “see” where we are putting the cream and making theapplication, And therefore the final result, more homogeneous.
How long does the effect last?
The reaction that produces the color occurs a surface: it only affects the cells of the corneous layer, which are physiologically eliminated over the days thanks to the mobile turnover. That’s why the effect of self -tanning tends to disappear quite quickly.
Furthermore, it is important to underline how the “tan” from DHA is only a simulation of the real tan, it has nothing to do with the melanogenesis (the production of melanin) and consequently It does not offer any sun protection. It is therefore recommended to avoid intense exhibitions at least in the early hours, and, above all, of Apply protection: you should absolutely not confuse self -tanning and solar creams, they are two products different.
