It’s no secret that skincare companies make a fortune through our desire to take care of our skin, and in recent years there has been an uptick in marketing efforts around ‘probiotic’ skincare or microbiome-friendly skincare (and concurrently a number of articles looking at whether probiotic skincare is a lie or not). This Pretty Light Science article takes a closer look at what researchers are saying about probiotics in skincare.
Probiotics defined
Probiotics are defined as “live microorganisms that, when administered in adequate amounts, confer a health benefit on the host” [1]. Probiotics are used to supplement a person’s existing microbiome. You may have been encouraged by your doctor to take probiotics after completing a round of antibiotics—with the idea being that the probiotics could help restore your intestinal microbiota after being disrupted by antibiotics [2]. There’s a fair amount of marketing around probiotics in yogurt, kombucha, kimchi, and other products that claim to help with digestion.
In recent years, probiotics have even been added to cosmetics, with the idea that the ‘good’ microbes present in the product can improve your skin’s appearance and health.
Other examples of products claiming to contain probiotics include deodorants and toothpastes that aim to ‘balance’ your oral and armpit microbiome to prevent tooth decay and odor, respectively. While the idea of nurturing the complex ecosystem that lives on our skin in order to look, feel, and even smell our best is alluring…it almost sounds too good to be true. But is it?
How are probiotics used in skincare?
Skin is the largest organ on the human body, so it stands to reason that what we apply to it (or don’t) can have an impact in our day to day lives [3]. The microbes that live on our skin are considered mutualistic, meaning that they benefit by living on our skin and that we receive benefits of having them around. These mutualistic microorganisms prevent the colonization of pathogenic microbes on our skin. However, this community of microbes has to work to maintain a delicate ecosystem and if that gets upset, dysbiosis occurs which can then result in undesirable skin conditions including acne or atopic dermatitis.
Probiotics that are put on to skin fall into the category of topical probiotics, which aren’t regulated by the US FDA. This lack of regulation means that when you see probiotic-infused creams or other probiotic beauty products, it’s worth checking the ingredient list. One reason for this is that topical probiotics are usually not true probiotics as they don’t contain living microbes but instead contain components or derivatives of probiotic microbes—e.g., lysed or broken up cells, fermented by-products, or filtrates. Postbiotics is a term that has been proposed for these probiotic-like products [4]. The reason that topical probiotic skincare likely won’t contain true probiotics can be linked to rules around the acceptable concentration of live microbes in a skincare product (for obvious safety concerns). Additionally, many probiotic microbes are sensitive to oxygen which makes keeping a viable microbial culture in something like a tube of skin cream technically challenging. After covering what probiotics actually are, let’s tackle the question of what they can do for a human body?
Are probiotics in skincare effective?
Studies have found that both postbiotics and true probiotics can be beneficial to the skin [4,5]. Many studies have identified a skin-related benefit when probiotics were taken orally to help treat a specific skin condition. Examples of skin conditions that have been studied in relation to orally administered probiotics include acne, dermatitis, and psoriasis. Likewise, researchers have suggested that the use of probiotics can slow aging by improving physical qualities of the skin itself such as balancing pH and minimizing oxidative stress [5].
Moving one step closer to true probiotic-based cosmetics, some researchers have found that the application of specific strains of bacteria results in positive changes to the skin. When Nitrosomonas eutropha was applied to skin, researchers found that the depth of wrinkles was significantly reduced, suggesting that if applied at a high enough concentration, this microbe might be a promising anti-aging treatment [6]. Another study found that a cream containing Streptococcus thermophilus (commonly found in yogurt) resulted in a significant increase in ceramide concentrations which helps to moisturize and strengthen the protective skin moisture barrier. These results were also found when a postbiotic version of the cream (containing an enzyme called sphingomyelinase) was used instead [7].
It is important to note that studies with larger cohorts and over longer time scales are still needed, especially for topical probiotics, therefore it’s difficult to make a generalized statement around whether probiotics in skincare ‘work’ or not. Further, topical probiotics are not regulated by the FDA, meaning that there’s no sure-fire way to know if the product you’re putting on your skin has actually been shown to do what it claims to [8].
In conclusion
Oral probiotics have been shown in several studies to provide some benefits to skin health (especially when there is some level of skin dysbiosis occurring).
Fewer, promising studies exist on topical probiotics but skepticism is warranted due to the lack of FDA regulation.
The human microbiome is a complex ecosystem that researchers are still working to understand, so it’s recommended to always approach any product that claims to ‘balance’ it with a healthy dose of skepticism.
This article was written by Courtney Thomas and edited by Alexey Vorobev.
References:
Hill, C, Guarner, F, Reid, G. et al. 2014. The International Scientific Association for Probiotics and Prebiotics consensus statement on the scope and appropriate use of the term probiotic. Nat Rev Gastroenterol Hepatol 11, 506–514.
Liao W, Chen C, Wen T, Zhao Q. 2021 Probiotics for the Prevention of Antibiotic-associated Diarrhea in Adults: A Meta-Analysis of Randomized Placebo-Controlled Trials. J Clin Gastroenterol.
How does the skin work. Accessed August 2023. https://www.ncbi.nlm.nih.gov/books/NBK279255/
Salminen, S, Collado, MC, Endo, A. et al. 2021. The International Scientific Association of Probiotics and Prebiotics (ISAPP) consensus statement on the definition and scope of postbiotics. Nat Rev Gastroenterol Hepatol 18, 649–667.
França K. 2021. Topical Probiotics in Dermatological Therapy and Skincare: A Concise Review. Dermatol Ther (Heidelb).
Notay M, Saric-Bosanac S, Vaughn AR, et al. 2020. The use of topical Nitrosomonas eutropha for cosmetic improvement of facial wrinkles. J Cosmet Dermatol.
Di Marzio L, Cinque B, De Simone C, Cifone MG. 1999. Effect of the lactic acid bacterium Streptococcus thermophilus on ceramide levels in human keratinocytes in vitro and stratum corneum in vivo. J Invest Dermatol.
Lee, GR, Maarouf, M, Hendricks, AJ, et al. 2019. Topical probiotics: the unknowns behind their rising popularity. Dermatology Online Journal, 25(5).
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