The ingredient retinol, which is widely added to anti-ageing skincare products, may improve skin health through its effect on the skin microbiome.
When applied topically, retinol gets converted into a nutrient called retinoic acid. Lab studies suggest that and degradation of the protein collagen, which may reduce the physical signs of ageing.
Applying different types of , but it is unclear how these microbes interact with retinol specifically.
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To learn more, at Tsinghua University in China and his colleagues 鈥� including people at the skincare company HBN 鈥� recruited nine Chinese women aged between 22 and 38 years old. They were asked to use a lotion developed by HBN containing 0.15 per cent retinol each evening for 28 days, while avoiding other leave-on skincare.
The researchers collected skin swabs on the first day and every week later. They then extracted DNA from the swabs, which they sequenced to map the women鈥檚 skin microbiomes.
After the first week, the women had reduced levels of the bacteria Stenotrophomonas maltophilia and Pseudomonas species, which can cause skin and soft tissue infections. Testing the moisture content of the women鈥檚 skin throughout the trial also suggests that the lotion improves skin hydration, .
The team thinks two types of microbes 鈥� Corynebacterium kefirresidentii and Sericytochromatia species 鈥� are involved in the first step of the reaction that converts retinol into retinoic acid. This is based on the high rate at which these bacteria produced metabolites, products of reactions within cells, that are involved in the conversion.
In another part of the experiment, the researchers analysed the swabs for metabolites of a low molecular weight involved in skin cell reactions, . The lotion was linked to an increase in metabolites associated with the production of vitamin B1, which has been linked to skin cell repair and maintaining a healthy barrier to retain moisture.
鈥淭here is a significant need in the research community to understand what skin microbiota are doing, which this study has addressed by assessing skin metabolites,鈥� says at the University of Hull in the UK. She says that the study should be extended to include older people and those of different ethnicities to assess retinol鈥檚 effects more broadly.
bioRxiv
