Self-tanning products are essential for achieving a natural sun-kissed complexion without exposure to solar radiation. While the texture has been improved to prevent skin dryness and the often-dreaded orange hue is now under control, the "unpleasant" smell that self-tanners are said to emit still deters some consumers. What causes this? What improvements have been made in this regard?
What is the source of the distinctive smell of self-tanning products?
Summary
Published on October 2, 2024, by Stéphanie, PhD, Doctorate in Life and Health Sciences — 3 min of reading
Themes:
Self-tanners: A distinctive smell linked to the formulation.
Many complain about thechemical and acrid smell emitted by self-tanning products. This smell is inherent in the formulation of the self-tanner and comes from the main active ingredient responsible for giving the skin a sun-kissed glow: dihydroxyacetone (DHA). More specifically, it is the Maillard reaction of DHA with the amino acids in the stratum corneum that is responsible for the unpleasant smell so characteristic of self-tanners, releasing volatile and odorous compounds including heterocycles, before chemically creating melanoidins through polymerisation.
Is it possible to mask the development of this unpleasant odour?
These odours associated with DHA are almost non-existent today thanks to the advancements made by brands. Some self-tanners have a fairly neutral smell due to odour sensor systems, or masking agents (ex : zinc ricinoleate, etc...). They have the ability to absorb odorous molecules. Others add fragrances and essential oils to the formula in order to mask the emanation related to dihydroxyacetone. However, in this case, it is not mandatory to mention the detail of the fragrance in the INCI list, excluding allergenic substances listed in Annex III of the Cosmetic Regulation. As a precaution, especially for sensitive skin, it is advisable to avoid them nonetheless.
Our self-tanning formulas do not emit that much-dreaded smell upon application. No masking agents, essential oils, or fragrances have been added to disguise the scent.
But then, why use DHA in self-tanning formulas?
Although there are other self-tanning molecules (erythrulose, troxerutin...), DHA remains the most effective in local application and therefore the most used. Even though it acts like DHA, erythrulose acts more slowly and does not provide the same intensity of colouration. As for troxerutin, when used alone, it does not develop this much-anticipated browning effect. Tyrosine derivatives alone are also not capable of providing a sustained and lasting tint to the skin.
The DHA is a sugar that interacts with the amino acids of the corneocytes in the upper layer of the epidermis, thereby generating brown pigments, known as melanoidins, on the skin, giving a temporary "tanned" appearance, all without the risks of photodamage (melanoma, brown spots, photoaging, sunburn...).
Source
MARTINI M.-C. Self-tanners and artificial tanning products. Annals of Dermatology and Venereology (2017).
