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.
See, the more we learn about our skin microbiome, the more we come to understand just how important it is, just how badly we've been treating it, what that means for our bodies—and, perhaps most urgently, what we can do to restore it.
What is biotic skin care?
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.
Sometimes it's called biome-friendly skin care, microbiome skin care, microflora skin care, or a number of other phrases—but it's all the same category. Biotic skin care is the broad term in which we categorize products infused with biome-specific ingredients, like pre-, pro-, and postbiotics. The ingredients all work toward barrier support and nurturing a thriving microbial community; though, of course, the ingredients do so to varying degrees of efficacy and mechanisms (don't worry; we'll explain more shortly). What's also cool about these ingredients is that you can really use biotic skin care anywhere: face, body, and scalp, too.
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.
But to understand why and how biotic skin care does all of these good things for the skin, first we must understand the microbiome itself.
The skin microbiome: What it does & why keeping it healthy matters.
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.
As we wait with bated breath for new developments, here's what we know from the current research:
- Helps us deal with skin infections. "From what we can tell, a healthy skin microbiome protects against infection in much the same way a good gut microbiome does: by crowding out the overgrowth of pathogenic organisms," says Fitzgerald.
- Acts as a vital part of our skin barrier function. One of the skin's most important roles is acting as a barrier. The microflora is a vital part of that function and makes sure the skin is less permeable (read: bad stuff can seep through; good stuff can get out).
- Protects us from environmental damage. "The microbiome also aids in wound healing, limits exposure to allergens, minimizes oxidative damage, and keeps the skin plump and moist," she says. Additionally, there's some exciting research about the skin microbiome and photodamage: "There's really exciting research about the skin microbiome helping modulate damaging effects of UV exposure and using pre- and probiotics to protect against UV radiation1 through antioxidative, anti-inflammatory, anti-aging," says Barr.
- Communicates with our immune system. "We once thought that our microbiome only existed on the surface of the skin and that the deeper dermal layers were sterile. We now know that's not true as scientists did a deep dive2 into the dermis looking for microbes, which were found all the way to the subcutaneous fat layer," she says about the 2013 study published in Nature Communications. "While the researchers noted that more studies are needed, it appears that the most intimate communication between the microbiome and our immune system takes place at this layer."
What affects the microbiome?
A not so inconsequential part of this conversation are the things that can negatively affect your microbiome. Why? Because taking care of your skin is just as much about what you do to your skin as you don't do to it.
- pH-disrupting topicals. Your skin is naturally acidic, hovering at around a pH of 5. This is important because the healthy microorganisms on your skin prefer a more acidic environment. Whatever you put on your skin—be it water, DIY tonics, or topicals—does temporarily affect that base level. And while your skin has an impressive ability to bounce back, when your pH is disrupted too dramatically or too frequently, it can create an environment for the "bad" bacteria to thrive.
- Sulfates and harsh surfactants. Sulfates and harsh surfactants do a few things to the skin: First, they disrupt the stratum corneum, which in turn, affects the environment in which good bacteria thrive. They are also very alkaline, which will affect the pH (see above). Finally, they strip the skin of the natural oils, which can also influence the balance, as it's a vital part of the skin barrier.
- Age and lifestyle. There are also normal, natural reasons your microbiome shifts. The most notable is age: The microflora changes over time, as we go through hormonal shifts, and so on. (For example, some strains of bacteria are heavily present in puberty but then lessen as we reach our 20s and beyond.) Lifestyle can also play a role in the density of our microbiome: Those who spend more time in nature tend to have a more diverse set, for example.
What are probiotics?
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.
As this is the area of biotic skin care that's been around the longest, there are more studies to back up the claims. Several studies indicate that topical probiotics may help ease the symptoms of skin conditions3 like acne, eczema, rosacea, and other inflammatory issues. Other studies show that probiotics can help your skin's immune response4, as well as dealing with outside stressors such as UV exposure. Finally, emerging studies think that they can help the skin as it ages5—likely due to tempering inflammation.
What's the problem with probiotic skin care?
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.
What does this mean in practice? Once you slather said probiotic product on your face, the chance that those organisms are still living isn't high. Some cosmetic chemists use innovative technologies to ensure they stay active—so be sure to use brands that are able to provide evidence that their probiotics are still beneficial.
What probiotic strains should you look for in skin care?
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.
What's more important is that you should look for brands that are able to show that their technology ensures the stability of the living organisms (a few brands, like LaForce or Mother Dirt) make these claims. If a brand is hyping "probiotic" technology, but can't show proof of living organisms it's likely that the formula actually contains lysates or para-probitoics. Lysates are fragments of fermented bacteria and para-probiotics are dead probiotics. Currently, there's conflicting evidence if these are helpful for the skin, or if they can actually increase inflammation on the skin.
- Lactobacillus: This strain is particularly effective at dealing with inflammation and skin barrier function6 as it's able to help your skin produce antimicrobial peptides, studies show.
- Bifidobacterium: According to research, this strain can help ease water loss and improve the symptoms of reactive skin7, thanks to its ability to help your skin produce ceramides.
What are prebiotics?
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.
However, there are some ingredients that have a bit more of a prebiotic effect than others: namely plant sugars, algae, and minerals. (These are what we typically think of when we think of prebiotic ingredients.) While prebiotics haven't been studied to the same extent, studies show that they can support skin barrier function8—especially when paired with probiotics.
What prebiotics should you look for in skin care?
Since prebiotics are much more varied, there are several ingredients that could be considered to have a prebiotic effect:
- Minerals, like magnesium and calcium
What are postbiotics?
Postbiotics are the latest, most advanced iteration on biotic skin care. Researchers have been able to identify very important outputs from the bacteria living on our skin9. These are things such as peptides and short-chain fatty acids. The idea here is that rather than replanting the bacterial strains (as in probiotics) or feeding the strains we have naturally (prebiotics), postbiotics do the work and supply skin with these natural byproducts from the start.
What postbiotics should you look for in skin care?
Postbiotics are a relatively new discovery in health, so the short answer is that brands haven't started using postbiotic language or used it in their formulas (although experts note to keep an eye out for some to hit the market—they're poised to be the next big thing).
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."
For context, live lactobacillus is a strain of bacteria found on the skin—in fact, it's the main bacteria that lives on the skin when we're younger, and it performs a host of duties that help our skin thrive, regenerate, and grow. However, we lose it as we age10—as we do many bacteria strains. But by feeding your skin the fermented version, you’re essentially giving your skin all the benefits of the bacteria without having to reintroduce the live version onto the skin. As you can imagine, this process tends to be more effective.
Skin barrier function: How this all plays a role in your skin's most important responsibility.
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."
Supporting your skin barrier isn't about superficial aesthetics—there are internal repercussions to disregarding the health of your skin and microbiome. In one 2019 study, researchers found a major link between skin dysfunction and various health conditions caused by chronic inflammation. In the study, researchers connected the use of barrier repair moisturizers with reduced pro-inflammatory cytokines in the blood, highlighting the importance of the skin's protective role in our overall health: Namely, that poor barrier function is linked to inflammation that can trigger internal health conditions.
As we learn more about the skin and its own microbiome, we learn just how important it is that we tend to it as best we can. This means treating it gently in the first place, but it also means using topicals that can help it thrive with the help of advanced skin care technology.
Alexandra Engler is the beauty director at mindbodygreen and host of the beauty podcast Clean Beauty School. Previously, she's held beauty roles at Harper's Bazaar, Marie Claire, SELF, and Cosmopolitan; her byline has appeared in Esquire, Sports Illustrated, and Allure.com. In her current role, she covers all the latest trends in the clean and natural beauty space, as well as lifestyle topics, such as travel. She received her journalism degree from Marquette University, graduating first in the department. She lives in Brooklyn, New York.