The secret microverse of the skin
I am sure we have all heard about probiotics – in our yogurts, cheese…and skin care, but before I get to that. The microbiome is defined as “The collection of all the microorganisms (bacteria, archaea, fungi, protozoa and viruses) that live in a particular environment or biome, their genomes and the surrounding environmental conditions including microbial metabolites (RNA, proteins, short-chain fatty acids)”. The microbiome is sensitive to harsh cleansers or extreme shifts in pH and so it is important to understand what it is, so we can protect it as it keeps our skin healthy.
What is Probiotic Skincare?
Probiotic skincare is just as it sounds, all our products that we love but with added beneficial microbes. By adding in extracts of l. acidophilus and other probiotics to a formulation, beneficial bacteria are delivered directly to the skin. Research has shown probiotics to help strengthen the skin’s surface, enhance moisture retention, fight sensitivity, improves dryness and redness, and helps to balance the acid mantle .
Probiotic cosmetic formulations contain 4 different kinds of probiotic preparations; fermentation products, cell lysates, tyndallization or living extractions. Fermentation products are without any bacteria, just their peptides etc. Cell lysates is when a chemist intentionally breaks open the probiotic bacteria cells and bottles it unfiltered. Tyndallization is heat killing the cells so they can no longer proliferate, but still remain active. Lastly, living is as it sounds.
How Probiotics Benefit Skin
The skin’s surface is akin to a multifaceted environment – the microcosmos – and probiotics are responsible for keeping the skin’s biology in balance. Resident probiotics work to prevent colonization of other pathogenic bacteria or opportunistic infections by competing for essential nutrients, producing fatty acids, lowering pH within microenvironments on the skin and producing bacteriocins. Probiotics also stimulate the skin’s immune system and specifically stimulate the epithelial cells to secrete small antimicrobial peptides called defensins, cathelicidins and other smaller peptides. The skin microflora includes propionibacteria, Malassezia spp., micrococci and corynebacteria and together with prebiotics (fermentable carbohydrates like chicory) they produce beneficial metabolites that stimulate different metabolic pathways in the human body. 
What Does the Science Say?
In one study, Nodake and coworkers noted a facial gel preparation of S. epidermidis applied topically for 4 weeks significantly increased moisture retention.  Other studies have shown topical application of lactobacillus to protect from UV radiation  as well as reducing the time it takes for acne scars to heal!  Bottom line, you need to incorporate probiotics into your skincare so you can have a chance against the daily onslaught of environmental toxins (ozone, car pollution). I recommend Étymologie’s Probiotic Vitamin C Serum for a 1-2 punch of beneficial probiotics, high linoleic-acid omegas and Vitamin C. This formulation uses tetrahexyldecyl ascorbate for a more stable analogue of ascorbic acid, so you get every last molecule of what you paid for!
Written by Jamie Stanton B.Sc, @jamie_the_chemist
References R. Sfriso et al. “Revealing the secret life of skin – with the microbiome you never walk alone.” I nternational Journal of Cosmetic Science, 2020, 42, 117 & 121  microbiome844. (2018). [SEM Image]. Autism Mutation Alters Balance of Gut Bacteria in Mice. https://s3.amazonaws.com/spectrumnews-web-assets/wp-content/uploads/2018/06/2713241 8/microbiome844.jpg  What Is Probiotic Skin Care? | Paula’s Choice. (n.d.). Paula’s Choice Skincare. Retrieved August 11, 2020, fromhttps://www.paulaschoice.com/expert-advice/skincare-advice/anti-aging-wrinkles/everything-y ou-need-know-about-probiotics-skin.html  Donald S. Orth, Orth Consulting LLC. (2013, October 21). The Probiotic Nature of Normal Microflora. Cosmetics & Toiletries. https://www.cosmeticsandtoiletries.com/research/biology/premium-the-probiotic-nature-of-nor mal-microflora-227716701.html  Schaefer, K. C. T. M. (2013, July 24). Balancing Skins Microflora with Probiotics. Cosmetics & Toiletries.https://www.cosmeticsandtoiletries.com/formulating/category/skincare/premium-balancing-sk ins-microflora-with-probiotics-216806631.html?page=2  Muizzuddin N, Maher W, Sullivan M, Schnittger S, Mammone T. Physiological effect of a probiotic on skin. J Cosmet Sci. 2012;63(6):385-395.