The human skin provides a protective barrier and contains various microbial communities. Environmental factors such as poor nutrition and harsh surroundings can damage the skin, leading to dryness, acidic skin and infections. Probiotics and their derivatives have been studied for their ability to protect the skin, and there is a growing trend in developing cosmetic products that contain probiotics.

This study investigated the moisturizing effect of a moisturizer incorporating paraprobiotics (moist heat-inactivated Bifidobacterium lactis [B. Lactis], Lactobacillus plantarum [L. Plantarum])-containing moisturizer (APM) on the skin and its influence on the skin microbiome in healthy individuals. A group of 50 healthy individuals was randomized to treatment or control groups, and a paraprobiotic-containing moisturizer or a placebo was applied to the skin of their right forehand.

The study monitored changes in skin moisture levels and transepidermal water loss (TEWL) over 4 hours and after 4 weeks of treatment. It collected skin swab samples before and after the 4 weeks of treatment for microbiome analysis using next-generation sequencing technology.

The results showed that:

•  APM treatment significantly reduced the TEWL and increased the stratum corneum moisture values than the respective baseline values and controls. 
• The sequencing study revealed significant changes in Cutibacterium, Corynebacterium and Acinetobacter in the treatment group. 
• Nonsignificant changes in the phylum. However, considering the relative frequency, there was decreased abundance of the phylum Proteobacteria and Firmicutes and Cyanobacterial, while increased abundance of Planctomycetes, Chloroflexi, Verrucomicrobia and Gemmatimonadetes after treatment. 
• Additionally, the APM treatment suppressed Corynebacterium tuberculostearicum in healthy subjects. 

This study points out that APM could improve skin hydration and skin-beneficial microbial composition. Further studies must evaluate and henceforth promote the development of the para probiotics-based skin care formulations.

Source: Chaiyasut C, Sivamaruthi BS, Tansrisook C, Peerajan S, Chaiyasut K, Bharathi M. Influence of paraprobiotics-containing moisturizer on skin hydration and microbiome: a preliminary study. Appl Sci. 2022;12(23):12483.