The skin is the biggest organ of the human body. It is colonized by beneficial microorganisms that are responsible for protection against invading pathogens, the education of our immune system, and the breakdown of natural products. In circumstances where the skin barrier is broken or when the balance between commensals and pathogenic bacteria is disturbed, skin diseases or even systemic diseases can develop.

So, how can we improve our skin microbiome? One method that has gained attention is the use of topical skin probiotics – which means applying live microorganisms to the skin to improve its health. The first report of ‘topical bacteriotherapy’ for acne and seborrhea was published in 1912. Since then, dozens of skincare companies are selling what they describe as probiotic products, from serums to cleansers and moisturizers.

One of the problems of using live microorganisms in skincare products is the difficulty in keeping bacteria alive during manufacturing and distribution processes. Therefore, many companies replace them with prebiotics or postbiotics in their compositions. Prebiotics represent nutrients that feed and stimulate the growth of beneficial bacteria; postbiotics, on the other hand, are compounds made by these beneficial bacteria.

In addition to these topical skincare products, there is a new class of cosmetics called nutricosmetics. They are dietary supplements, food, or beverage products with additives that are marketed as having medical benefits that improve appearance. They are designed to enhance beauty from within, normally targeting skin, hair or nail health. Several compounds can be classified as nutricosmetic ingredients, for example, collagen, vitamin C, and omega-3 fatty acids, and also probiotics, prebiotics and postbiotics.

However, the use of these compounds to improve the skin microbiome has been difficult to prove. Few clinical studies have been able to prove beneficial effects on the skin microbiome after the use of prebiotics, probiotics, postbiotics or nutricosmetics. For the most part, studies fail to show any beneficial effects or to correlate observed effects found with the use of these products.

On the other hand, normal skin care such as hydration, cleansing, and protection of the skin from UV damage helps to create an environment that is more hospitable for these beneficial organisms, thereby assisting our skin’s natural microbiome to flourish.

For more information:

https://www.bbc.com/future/article/20250401-your-skin-has-a-microbiome-of-its-own-does-taking-probiotics-help

Byrd AL, Belkaid Y, Segre JA. The human skin microbiome. Nat Rev Microbiol. 2018 Mar;16(3):143-155. doi: 10.1038/nrmicro.2017.157. Epub 2018 Jan 15. PMID: 29332945.