M. Brandt, K. Unbereit, G. Springmann, S. Bielfeldt
Quality seals being precisely defined, transparent and validated could help consumers in their decision making. This applies particularly for new categories of cosmetics e.g. those related to the human skin microbiome The knowledge on the human skin’s microbiome grows rapidly and a huge number of cosmetic products with ‘microbiome’ claims are now seen on the global market. Developing a credible and valid quality seal for supporting approved claims on skin microbiome is challenging. Here we propose standards for a quality seal for cosmetic products claiming to be ‘microbiome friendly’. We assume that such a claim can be made if: there is no significant change in microbial diversity as measured by e.g. the Shannon Index and there is also no significant dissimilarity between untreated and treated skin as measured by main component analysis (e.g. Unifrac distances); Also, it should be controlled that there is no strong increase or decrease in the abundance of single microbe genera. Further, evaluation of the skin in terms of clinical safety, skin pH and barrier integrity should also be performed.