If you're reading this, I owe you an apology. About six years ago, there was a sudden rise in the number of products that claimed to optimize the skin's microbiome, the collection of microorganisms living on its surface. The formulas contained probiotics, or live microorganisms derived from fermented foods or dirt, for example.
But no matter the source, the storyline was the same: These probiotics were said to rebalance your skin's microbiome by adding "good" bacteria that then (by a somewhat acrobatic leap of logic) could edge out the alleged "bad" bacteria and, in turn, among other things, reduce inflammation — thus bestowing you with happier, healthier skin.
Parts of that story hold true, but if you string them together with a daisy chain of Boolean logic (if this, then that), probiotic-laced skin care ends up wearing a halo of scientific truth. But like all halos, it's not real. That's the mistake I (and many other editors) made when reporting on this phenomena in the mid-teens.
What We Know About the Skin's Microbiome
What we knew then: There was — and is — plenty of research linking microbiome imbalances in the skin and gut to inflammatory skin conditions such as acne, rosacea, and eczema (there have been ample papers published in journals such as Clinics in Dermatology, the Journal of Investigative Dermatology, and the Journal of the American Academy of Dermatology). There are also plenty of people who have taken probiotic-infused skin-care products for a test drive and swear up and down that they work.
What I know now: On a video call with scientist Larry Weiss, the now-unaffiliated founding chief medical officer of one of those mid-teens, probiotic-based brands, something caught my attention. He said we can't claim to "recolonize" the facial microbiome with skin care, even if it contains promising probiotics. Skin care with certain probiotics can potentially affect (and possibly benefit) our skin until it is washed away or those live microorganisms die, but it's not fundamentally changing the microbiotic landscape on our skin, as I had reported.
Do Probiotics Have Any Benefits for Skin?
So now, as a new wave of probiotic skin-care crests, I come from the past to set the record straight. There's a laundry list of issues with putting faith in probiotic skin care (and "issues" is a nice word for it). Even the world's foremost microbiome researchers can't say for certain which specific strains of probiotics will have a lasting — or even short-term — effect on the skin, or how much of them we need to see a difference. "The science right now has revealed promising leads, but nothing particularly solid," says Tami Lieberman, an assistant professor at MIT's Institute for Medical Engineering and Science, who researches the principles governing colonization and personalization in the human microbiome.
For instance, today a type of bacteria called lactobacillus is used in probiotic creams and serums for all the wrong reasons, says Teo Soleymani, M.D., a dermatologist at UCLA Health. He says it's popular because it's one of the few bugs that will play nicely and stay alive in an unrefrigerated cosmetic formulation, not because it's a predominant strain on healthy human facial skin (it's not), nor because we have firm data suggesting that smoothing it on does your skin any favors (we don't).
Another issue: The bulk of research on helpful probiotic therapies focuses on the microbiome or pathways in the gut, not the skin. (The main probiotic commonly prescribed, called VSL#3, is used to treat gastroenterological issues, like ulcerative colitis, says Robert Urban, a pharmacist in San Diego.)
Unfortunately, the benefits are not interchangeable. In fact, microbiologists including Kristin Neumann, who runs an independent lab in Erlangen, Germany, say there are more similarities between the facial microbiomes of two complete strangers than the gut microbiome and facial microbiome of the same person. And that can be a good thing. "In many ways, the skin microbiome offers more potential for universal solutions than the gut microbiome," Lieberman says. "There are microbial species that live on nearly everybody's skin, where that is not true in the gut. The microbial community is less complex on the face."
The bummer is that after scientists zero in on those miracle microbes, there will be a few more hurdles to jump. The highest hurdle, according to the experts I spoke with, is dosage. "We have no idea about the dosage [skin needs], whether the active ingredient is active, and how long it will survive on your skin," Dr. Soleymani says. Most probiotics used in skin care today aren't still-living microorganisms in the first place, which means they aren't likely to produce any of the promising benefits in studies, even if a formula is packed with them. Once an effective dosage is determined, scientists and chemists will need to figure out how to deliver that effective dose of (probably live) microbes in a stable formula at room temperature, or with the aid of refrigeration (making it very, very expensive), and make sure they survive on the skin long enough to do any good.
The Future of Probiotic Skin Care
So is probiotic skin care a bunch of bunk? No, quite the opposite. Probiotic skin care has the potential to change the entire skin-care game — just not in the way we thought. "In the future, I could have a probiotic [microorganism] that lives on my face that secretes sun [protection] when I go out into the sun. You could imagine doing such things for any desired effect," Lieberman says. Weiss concurs, adding that probiotics also have the potential to deliver ceramides, acids, and other nutrients at beneficial levels without the need for constant reapplication.
For now, though, we'll have to care for our biomes the old-fashioned way: "Improving and diversifying your biome takes time and work," says Heather D. Rogers, M.D., a board-certified dermatologist and dermatologic surgeon in Seattle. Dr. Rogers suggests introducing healthy bacterias into your body through fermented foods, like yogurt and kimchi, but as we said, it remains to be seen how doing so might impact your skin.
The future is coming, it's just not here quite yet.
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