The last few years have engendered a panicked crash course in viruses and how they function, and thus an inescapable awareness of the tiny particles living on our hands and faces. The coronavirus notwithstanding, though, the vast ecosystem of bacteria, fungi and viruses found on the body’s largest organ are not always adversarial. “Among their contributions to our health and survival, our skin microbes serve as the first line of defence — protecting us from infection and modulating our immune system,” says Dr Larry Weiss, the founder of the San Francisco-based skin-care brand Symbiome.
Manipulating these microbes is an increasingly popular aim for beauty brands, as evidenced by a wave of new products that tout probiotics, prebiotics or postbiotics as ingredients. While scientists still argue about the exact benefits of these particles, which are more commonly ingested via health drinks or supplements in attempts to aid digestion or boost immunity, some skin-care lines claim that, when applied topically, they help the body’s exterior layer stay in a state of bacterial harmony, therefore “offsetting the factors that lead to redness, dryness and a weakened surface” — or so says Dr Shereene Idriss, the founder of the New York-based practice Idriss Dermatology. “Then there’s less inflammation overall and that, in the long run, can slow down the signs of aging.”
Before you revamp the contents of your medicine cabinet, it’s worth reacquainting yourself with the basic definitions: probiotics are live microorganisms thought to provide health benefits. Prebiotics are the nutritional materials consumed by those microorganisms, and postbiotics are what they produce. “It’s like ‘Star Wars’ happening on the surface of skin,” says Dahlia Devkota, the founder of the Los Angeles-based skin-care brand Editrix, which makes products with both pre- and postbiotics. “‘Good’ and ‘bad’ bacteria both excrete postbiotics, which are their weapons of war. The goal is a balance of both with no one species taking over.”
Certain products or treatments can, at least in theory, help maintain that balance and provide specific benefits. After all, that old beauty trick — a simple yoghurt mask — was used by the Greeks millenniums ago and has been adopted
by many other cultures since. The lactic acid produced by the probiotics in the food can break down dead skin cells, gently exfoliating the skin and brightening its tone.
While a yoghurt treatment remains affordable and accessible — just stop by the dairy aisle of your local grocery store — new products promise exfoliation and more. Earlier this year, the New York-based skin-care brand Holifrog launched its Utopia Microflora Toner, a watery formula meant to be applied after cleansing that, unlike traditional toners, doesn’t strip the skin. It contains isolates of Lactobacillus bulgarius, a probiotic, and oligosaccharides prebiotics, which the brand says will improve skin tone and elasticity by promoting cellular renewal, speeding up skin repair and increasing collagen synthesis. The Swiss brand Valmont uses similar ingredients in its Primary line, devised specifically to protect and encourage balance in the skin’s microbiome. Its Primary Cream, a light formula that soothes and strengthens, is particularly well suited for acne-prone skin because of its inclusion of panthenol (also known as vitamin B5) and lactic acid.
The products of the Los Angeles-based skin-care brand Venn, many of which contain pre- and postbiotics, are the result of decades of microbiome research conducted in South Korea by the label’s scientific advisory board. Its Synbiotic Defense Mist improves upon typical water-based face mists, which quickly evaporate and leave the skin dry again. “We replaced water with probiotic ferments,” says Venn’s founder, Brian Oh. “The probiotics get broken down into postbiotics, including hyaluronic acid, vitamins and peptides, which nourish and hydrate.”
Oh’s isn’t the only company experimenting with fermentation, or the process by which microbes like probiotics break down organic molecules. “Because fermentation makes the molecules smaller, the product can penetrate the skin surface more deeply,” says Jeff Rosevear, the head of skin-care research and development for new brands at Unilever; the company recently launched a line called Ferver in the United States, which has a serum made with fermented collagen. Symbiome also uses some fermented ingredients, as with its new body oil The Premise. It contains only six ingredients, five of them postbiotic oils that, before they’re fermented, are sourced sustainably from the Amazon.
The New York-based aesthetician Crystal Greene is partial to Devkota’s line, especially its Bakterium Delirium serum. She admires its ability to “nourish and build up the skin’s defences,” she says, by creating a balance of bacteria that supports the protective quality of the microbiome. In general, Greene recommends pro-, pre- and postbiotic-laden products to her clients because she finds them gentler than some of the other popular ones on the market. “Harsh stripping, cleansing, exfoliating and sterilising deplete and weaken the skin barrier, and I often see this in my private practice,” she says.
Indeed, while some commonly utilised active ingredients, such as retinol and benzoyl peroxide, do sensitise skin, there seems to be no downsides to using high concentrations of prebiotics and the like. “The beauty of skin care with pre- or postbiotics is that there are no known harmful side effects,” says the dermatologist Dr Lindsey Zubritsky. “With any new product, I recommend spot testing on the inside of your arm to ensure no allergic reaction, but these ingredients, specifically, are safe to use and beneficial for all skin types.”