If your skincare routine is designed to keep your skin absolutely sterile, we’ve got some news for you: Bacteria aren’t necessarily bad—and neither are viruses, fungi, or other microorganisms.
With that said, you shouldn’t stop washing your face, either, since many of those microorganisms are pretty bad.
Like many things related to skincare, it’s complicated. That’s because your skin is home to a microbiome of microscopic organisms.
Think back to your seventh-grade biology class, and you’ll remember that biomes are basically large communities in which organisms rely on each other in order to thrive. Our skin has its own microbiome, and like other biomes, it is delicately balanced. If you’re not careful, you can throw off that stability, and problems can arise.
“The skin is colonized by a diverse collection of microorganisms (including bacteria, fungi, and viruses), most of which are harmless or even beneficial to us as humans,” Tanya Kormeili, MD, a board-certified dermatologist in Santa Monica, California, writes in an email to HealthyWay. “Our immune systems can modulate the skin microbiota [the various organisms in the skin microbiome], but the microbiota also functions in educating the immune system.”
It’s can get dense and confusing, so we dove into the latest skin biome research to figure out what you need to know about the skin microbiome and healthy skin—and how to incorporate that knowledge into your skincare routines.
How (We Think) the Skin Microbiome Functions
The skin microbiome is remarkably complex, and researchers are still trying to understand how it works. We do know that the microorganisms play an essential role in helping our immune systems function, and there’s a whole lot of interplay between our bodies and the tiny bacteria and viruses living on its surface.
“[The microbiota] teaches our immune system and helps us regulate what is normal versus what is a true infection,” Kormeili writes. “This symbiotic relationship helps protect against invasion by more harmful organisms.”
In other words, the organisms on our skin help our bodies recognize and eliminate dangerous intruders.
Balance is key. Without a varied, diverse microbiome, we might not be able to mount a reaction to, say, Staphylococcus aureus, a pathogen thought to cause many of the cases of eczema (atopic dermatitis) in children. Likewise, if your skin microbiome is unbalanced, you might suffer from an overgrowth of Propionibacterium acnes, which is strongly associated with acne.
There are a few things to keep in mind about the skin microbiome and how this whole thing works.
- Our skin microbiota changes throughout our lives, so if one product or routine suddenly stops working, that may be the reason. For instance, infants typically have high concentrations of Firmicutes, a phylum of bacteria that can include Staphylococcus and Streptococcus, which can cause staph infections and strep throat, respectively. As we age, the concentrations of those Firmicutes bacteria decline, and gradually, our skin changes in terms of structure and function. As a result, our microbiome becomes more diverse, and our immune systems become more effective at addressing threats. Some research indicates that if infants don’t get a stable, diverse skin microbiome—like those common concentrations of Firmicutes—early in life, they’ll be more likely to have skin immunity problems as adults.
- Go thank your mom: One of the very first things that affects your skin microbiome is your birth. Research indicates that vaginal delivery results in a healthier immune system than cesarean delivery. Scientists believe that a mother’s body is set up to expose infants to the microbiota they’ll need to develop healthy immune responses. An infant’s skin is directly exposed to microorganisms during vaginal birth, and they also inevitably consume some of those bacteria orally. Breast milk is also thought to promote the growth of certain microbial communities, proving that kiddos really can get their glow from mom.
- Our microbiota can play a role in the development of a number of diseases—but those diseases aren’t necessarily infectious. As we’ve mentioned, our microbiome profoundly shapes the way that our immune system responds to threats. Your immune system might handle P. acnes—a common inhabitant in adult skin—fairly well. If you interact with a person who’s having an acne outbreak, your skin will effectively prevent those bacteria from overwhelming your defenses—mostly because you’ve probably got plenty of those P. acnes on your own skin to begin with. (For those same reasons, diseases like rosacea, psoriasis, and eczema aren’t considered contagious.)
- The concept of “good” and “bad” microorganisms is pretty outdated. Many bacteria and viruses don’t cause problems if they’re properly balanced in your skin microbiome. For instance, that P. acnes pathogen that causes acne is often harmless in the absence of other factors (for instance, excessive sebum production caused by our old friend, puberty).
- If you’re thinking about throwing out all of your soaps and cleansers, you may want to think again. Kormeili says that because the microbiome is incredibly complex, few dermatologists recommend a completely hands-off approach. “There are many environmental factors specific to the individual, such as occupation, clothing choice, and antibiotic usage, as well as inflammation or disease,” Kormeili explains. “What makes this even more complicated is that we have also an entire microbiome in our gut, and all these organisms have to live happily among our body’s cells!”
Do cosmetics make our skin microbiome less diverse?
We know that microbial diversity is typically a good thing because diverse microbiomes are often more stable. Microbial diversity seems to be useful when determining how external factors affect our skin, so we looked into whether our cosmetics harm the diversity of the microbiota.
Should we throw away our makeup brushes? (Not that we’re going to do that regardless, but should we?)
According to one recent study, cosmetics might actually make the facial skin microbiome more diverse. If you think about it, that makes sense; bacteria are everywhere, including in your makeup brush, and if microorganisms can survive the harsh environment of the human skin, they can certainly handle a little touch of foundation.
What about other products? We asked Kormeili whether cosmetics, cleansers, or other products could be upsetting the balance of our microbiota.
“The truth is that we are just starting to understand this,” she says. “We know over-cleaning and wiping out all the organisms is certainly bad. We also know that harmful organisms on the skin can cause true infections. The balance is yet to be fully understood. It is unclear what factors really drive variation in these organisms, and how fluctuation is associated with skin disease.”
She continues, “Cosmetics, soaps, hygienic products and moisturizers, and treatments are certainly capable of altering the skin microbiome. External factors such as humidity and temperature as well as UV light exposure also play a role. This relationship is so complex that we hardly truly understand it yet.”
In other words: Yes, your products are affecting your microbiome, but if you’re not having problems, you probably don’t need to change anything. If you are having issues, talk to your dermatologist.
How can we find a balance between cleanliness and a healthy microbiome?
“This is the multi-billion dollar question—still unanswered for the most part!” Kormeili tells us. “For example, molecular approaches examining bacterial diversity have found that the skin microbiota is dependent on the body site, so trying to balance a healthy microbiome is really body-site specific.”
A treatment that works extremely well for preventing bacterial overgrowths on your face might not work so well on a different part of your body, just as viruses that are harmless on the skin of your arm might pose more of a threat to the skin somewhere else. Of course, your immune system is there to fill in the gaps, which is why we don’t keel over every time we rub our faces with our often less-than-sanitary hands.
In one 2016 study, researchers looked at microbiome diversity among men from six different ethnic groups. The scientists took samples from three skin sites—forearm, below the shoulder, and scalp—and found that the men’s ethnicity didn’t affect microbiome diversity as much as the location of the sample did.
Interestingly, the researchers also found that microbiome diversity increased when the test subjects stopped using their regular shampoos and deodorants.
“Obviously, we cannot spend all day trying to ‘create a balance,’ and have to trust that the microbiome, if not altered, should do this on its own,” explains Kormeili. She recommends avoiding things that she says can “drastically ruin” the microbiome, including “harsh chemicals, antibiotics, antiseptics, or overuse of cleaning products or medications.”
Antibiotics seem to be a problem for the skin and gut microbiomes.
In 2017, researchers at the University of Pennsylvania showed that topical antibiotics were even more damaging to microbial communities on the skin than antiseptics, like hand sanitizers. That’s a good enough reason to avoid antibiotics unless you absolutely need them.
That did make us wonder: How do dermatologists avoid spreading bacteria and viruses from one person to the next, knowing that some of these methods could wreak havoc with patients’ microbiomes?
“We use very harsh chemicals in the office to clean every single aspect of the patient’s experience,” Kormeili writes. “We are worried sick about spreading the bad infections from one human to another.”
That said, she continues, “I always try to use a ‘global’ approach in each patient’s treatment regimen to avoid altering other aspects of their health when trying to improve their skin conditions.”
What that global approach will look like for you, though, is likely as unique as your microbiome is.
Keeping Your Skin Microbiome Healthy and Balanced
You may have seen probiotic products on store shelves that claim to improve skin health by introducing certain types of bacteria to the skin microbiome. Those claims are, at best, exaggerated, simply because the skin microbiome is so incredibly complex. What works for the skin microbiome seems to be extremely specific to the individual.
“In my experience, many of the commercially available probiotics are not standardized and often it is difficult to determine their activity,” says Amesh Adalja, MD, a board-certified infectious disease physician at the Johns Hopkins Center for Health Security.
“Microbiome-related therapies are in their infancy,” Adalja explains, “which makes it difficult for consumers to assess claims about various products, though in the future, I have no doubt such therapeutic products will be developed for conditions such as eczema.”
For the time being, you can assume that those products aren’t based in completely solid science, so Kormeili advises using common sense and practicing that holistic approach to health that she tries to use with her patients.
“It is so complicated. No one has the full answer,” she tells us. “Try to eat healthy to keep the right nutrients in the body for the right organisms to grow. Avoid foods that have pesticides, as they can potentially harm the gut microbiome. Avoid application of products that have hard alcohols and anti-bacterial effects, unless instructed [to] by a dermatologist.”
Finally, if you’re one of those people who won’t leave home without a tube of hand sanitizer, change your approach. Remember, there are plenty of helpful microbial organisms out there—you just can’t see them.
As Kormeili advises, “Do not become a germaphobe!”