Per- and polyfluoroalkyls used as cosmetic ingredients - Qualitative study of 765 cosmetic products.

Per- and polyfluoroalkyl substances (PFAS) form a vast family comprising more than 4700 synthetic compounds. Their molecules contain a terminal functional group and a hydrophobic carbon tail (alkyl group) at which the hydrogen atoms are totally (in the case of perfluorinated compounds) or partially (in the case of polyfluorinated compounds) replaced by fluorine atoms. Due to the very specific properties of their structure, they have been used in a vast range of applications over the last 70 years. These substances are considered to be of concern for the environment. Their effects on human health are still poorly understood because studies are still too rare, but the cutaneous route could be a significant pathway of penetration. In this context, we made a qualitative study to assess the presence of PFAS in various cosmetics such as hygiene products, skin care products, make-up and perfumes. Among the 765 products studied, we found 11 different PFAS. Polytetrafluoroethylene (PTFE) and perfluorodecalin, present in 25.9% and 22.2% of products containing it, respectively, were the most frequent. Although the presence of this type of ingredient seems to be limited in Europe, make-up appears to be the type of product most likely to contain PFAS.

A review of homemade cosmetics based on a study of 150 blogs and their authors.

Do-it-yourself methods have been used in many fields (cooking, home improvement, decoration, gardening, etc.) for a long time, but their application to the cosmetics sector is relatively recent and seems to be linked to a number of health scandals. The objective of this work is to analyse homemade cosmetics based on a study of blogs and their authors. We made a study of 150 blogs advocating homemade cosmetics. With only one exception, the blog authors were women, mostly in their thirties, with no specific qualifications or knowledge in the fields of cosmetic formulation or chemistry. The most highly qualified of them (with at least a Master's degree) had studied marketing and management. So, the situation is an illustration of the Dunning-Kruger effect, with authors believing themselves to be qualified in a field wholly outside their own. This leads to scientific falsehoods about, for example, preservatives like parabens and phenoxyethanol. On the contrary, the relevance of the ecological motivation frequently mentioned in these blogs is undeniable.

L'étude de 150 blogs prônant le DIY cosmétique nous a permis de mettre en évidence, qu'à une exception près, les auteurs étaient des femmes, des trentenaires pour la plupart, sans qualification particulière ni connaissance dans le domaine de la formulation cosmétique, ni dans celui de la chimie. Les plus diplômées (niveau Master minimum) ont suivi des formations orientées vers le marketing et le management. Nous avons donc ici une illustration de l'effet Dunning-Kruger, les auteurs s'estimant qualifiées dans un domaine qui n'est pas du tout le leur. Cela se traduit par des contre-vérités scientifiques sur les conservateurs, les parabens et le phénoxyéthanol, par exemple. Il ne faut, en revanche, pas nier la pertinence des motivations écologiques qui sont fréquemment évoquées dans ces blogs.