Biome-Friendly Skin Care: What To Know About Pre, Pro & Postbiotics

If there is a recent movement in skin care that has caught our attention, it has to be biotic and biome-friendly skin care. As beauty editors, experts, and insiders started digging into the various skin care breakthroughs, it became clear: This was one of the biggest developments in beauty in some time. But with newness comes the need for education—as well as some fact-checking.

In short: It's skin care designed and formulated to nurture your skin microbiome, or the collection of bacteria, fungus, and microorganisms that live on your skin. The emergence of this skin care subgenre has not happened overnight, either. It unfolded alongside the plethora of research developing about the role of the skin microbiome in our overall health, immunity, and skin barrier function. 

This is a vital step in skin care and the beauty industry because when your biome thrives—ideally the end result of these products—your skin is better able to stay hydrated, deal with inflammation, protect itself from environmental stressors, deal with skin conditions (like acne or rosacea), help your immune response, and age healthier. Sounds good, no? 

"No new skin care product that comes to market can claim to benefit the skin without keeping the microbiome in mind, using ingredients that support a healthy microbiome and avoiding ingredients that disrupt or damage the microbiome," says board-certified dermatologist Whitney Bowe, M.D.

You cannot have a conversation around these topicals without first understanding the many, many ways the microbiome influences the skin.

"As the largest and most visible organ, the skin not only gives clues into what's happening beneath the surface in terms of immune function, nutrition, oxidative stress, and metabolic issues, to name a few, but it's the body's first line of defense against infection, environmental stressors, and loss of nutrients and water, so addressing the skin is a gateway to overall health and well-being," says board-certified dermatologist Keira Barr, M.D. "The skin microbiome is constantly interacting with our environment and works to support our health by protecting against infection, influencing the immune response, protecting against UV radiation, and helping provide nourishment to the skin cells."

And what's even more exciting is that while we know the microbiome does a pretty significant amount of work already, it seems that there's also much to learn: "Research has just begun to piece together the important role they play in our health, and more exciting research is on the horizon," physician and naturopathic doctor Kara Fitzgerald, N.D., tells us. 

You've probably heard a thing or two about probiotics for your gut, and honestly, at this point, it's become fairly mainstream to talk about using probiotics topically. For example, have you ever slathered on a DIY yogurt mask? Well, you've used a probiotic product. 

The idea here is that much like we have the "good" bacteria that helps your gut thrive, we've also been able to identify many of the beneficial bacteria strains that live on your skin and support your barrier function. In an ideal world, we wouldn't need to do much to help these bacteria, as they strive for a balance naturally. But thanks to modern lifestyle changes, some skin care products, and oversanitization, we've disrupted that delicate balance—reducing the good flora and allowing the problematic inhabitants to more easily take hold. When you reintroduce the better-for-you items, you'll start to see a shift in your skin's makeup and behavior. 

However, recent evidence does cast doubt on the probiotic conversation. See the point of probiotics is that they are living organisms—but most living organisms aren't able to survive topical formulations, as topicals have to have preservative systems (of which the point is to kill bacteria, and they target both good and bad) and tend to have longer shelf lives (than, say, supplements).

"Live bacteria in skin care is overrated. More so, it's not even practical to have them because anytime you're looking at a cleanser, a moisturizer, or a cream, there are preservatives in there. And there is no way to have a living bacteria in that same product," says Bowe in this podcast episode. 

If you know anything about probiotics in general, you'll know that specific strains can perform specific functions. In the context of the gut, there are strains that reduce bloat, inflammation, and so on. With skin, there are two widely used strains you'll see often.

Prebiotics are a newer theme in skin care and are born of the idea that the living, dynamic shield that is your microbiome needs a certain amount of nutrients to help it keep on doing its job. You can think of prebiotics as food for probiotics. 

And while under the biotic umbrella, these are a bit less defined than probiotics. That's because, well, lots of good things can be considered food for healthy bacteria! Some derms and skin care experts go as far as saying that most barrier-supporting creams have some sort of prebiotic effect, as they are essentially enriching the bacteria on your skin.

Examples of postbiotics are peptides, like oligopeptides (peptides that range in chains of two to 20 amino acids), fatty acids (like medium-chain fatty acids, long-chain fatty acids, unsaturated fatty acids, polyunsaturated fatty acids), and biosurfactants. 

However, since these specific peptides and fatty acids are formed from fermented bacteria byproducts, they won't appear as the above on the ingredient label—instead, you'll see things like "lactobacillus ferment." 

As an organ, your skin has certain responsibilities: Your heart pumps blood, your lungs take in oxygen, and your skin acts as a barrier. Barrier function is its most vital task, and when that barrier is more permeable—or it's not functioning properly—things go wrong. It's sometimes referred to as a "leaky" skin barrier (sort of like a leaky gut), and it can act as an underlying cause of inflammatory skin conditions ranging from acne and eczema to even allergic reactions like hives.

"It protects us from mechanical injury, low humidity, cold, heat, sun, wind, chemical exposure, bacteria, viruses, fungi, and other pathogens," explains board-certified dermatologist Hadley King, M.D., stating that, "a healthy barrier is critical to normal skin function."