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.