What Your Skin’s Microbiome Says About You

You’ve likely heard about your gut’s microbiome—and how the right ratio of good to bad bacteria is key to digestive health. But your belly isn’t the only body part where bacteria balance matters. Your skin (i.e. your largest organ) also has a microbiome, and new research suggests it plays a crucial role in how your skin looks, feels and functions.

To get up to speed on why taking care of our skin’s microbiome is so important, we’ve asked Dr. Yug Varma, PhD, co-founder and CEO of Phyla Biotics, a microbiome research and development company, to outline the basics.

Why having bacteria on your skin is good 

“Think about the skin’s microbiome as this invisible rain forest, filled with diverse bacteria, that acts as a shield and protects you from disease,” says Dr. Varma.

“We used to think being healthy meant washing your hands all the time, using hand sanitizers making sure to eradicate all bacteria,” says Dr. Varma. “But now we know that if you kill all the bacteria on your skin, you convert the diverse, protective rainforest into a desert.” And a desert-like environment disrupts the healthy microbiome, making skin more vulnerable to issues like acne and eczema.

“There is growing evidence supporting the hypothesis that a loss of microbial diversity is the root cause of acne and possibly other diseases,” says Dr. Varma. “A researcher named Martin J. Blaser traveled to all these remote places in the world, like Africa and the Amazon, and studied the peoples’ skin microbiomes. What he found was incredible diversity and a lower incidence of many diseases.” 

What happens when we undervalue diversity 

“Let’s go back a generation. Peanut butter was once a dietary staple in kids’ school lunches, but today, they can’t have it. This is indicative of a rise in sensitivities, allergies and asthma. And we are seeing the same thing in skin,” says Dr. Varma. “A generation ago, the incidences of eczema were below 10 percent. Now it’s up to 15 percent, even higher in black children, and still rising. It’s imperative we get to the root cause and that means understanding how to protect and restore the diversity of the bacteria that protect us.”

Why diversity is key to healthy skin

“People with acne have a lower skin microbiome diversity than people without acne. There’s also been an analysis of the skin microbiomes of certain tribes, like the Yanomami in the Amazon, where they don’t get acne at all. Their microbiome is very diverse compared to ours in the U.S. It’s thought that microbiome diversity is a great marker for long-term skin health,” says Dr. Varma. “If we can boost microbiome diversity, we can certainly help people with acne. If we can do it in a targeted way for eczema and other inflammatory conditions, we believe we can help those conditions, too. The more diverse the microbiome, the healthier our skin is going to be.

Why the skin’s microbiome differs from head to toe

When it comes to the microbiome on skin, “there are three main types of habitats: wet, dry and oily,” says Dr. Varma. “The wet skin would include your armpits, your groin area, places that can be moist. The dry skin is most of the skin on our arms, legs, torso. Then your face, upper chest and upper back is a unique habitat, because it is oily or sebaceous.” 

How the skin’s microbiome is linked to acne

Acne is only associated with the areas of the body that have sebaceous glands (whereas eczema is primarily on the dry parts). “The face, chest and upper back change during puberty,” says Dr. Varma. “Your skin physiology changes. Your pores get deeper. The sebaceous glands activate and they produce a lot more oil. That’s why a lot of teenagers have oily skin. And when this oil production increases, you have an increase in a bacterium called C. acnes or Cutibacterium acnes, which are acne bacteria. Before puberty, you don’t find C. acnes on the skin at all. But after puberty and into adulthood, the percentage of C. acnes on the skin can range from 40 to 90 percent. It is the dominant bacteria in an adult’s facial microbiome.”

Acne is complex and it’s caused by many factors, such as diet, stress, hormones, and genetics. “But if you look at acne through the microbiome lens, the root cause is the overgrowth of the C. acnes,” says Dr. Varma. “And more young people than ever are suffering from acne—half of women in their twenties and a third in their thirties have acne. It’s certainly increasing.” One theory, says Dr. Varma, is that everything we’ve been using to treat acne, such as retinoids, antibiotics, and benzoyl peroxide, are all antibacterial in nature so they kill both the bad and the good bacteria. The result is a less diverse microbiome, and greater vulnerability to a chronic cycle of acne relapses. 

How to treat acne without killing the good bacteria

One strategy is to use phages, which are harmless viruses. “We’re covered by them, but they don’t interact with the human system at all,” says Dr. Varma. “They go after and kill bacteria,  and there are certain phages that specifically kill C. acnes bacteria,” says Dr. Varma, who suggests that using these phages in topical skin care may successfully treat acneic skin, without disrupting the microbiome balance.

How to encourage a diverse skin microbiome

“Overuse of any skincare is bad,” says Dr. Varma. “You want to find a balance. A simple, streamlined routine is less likely to disrupt the microbiome. I saw a survey that showed the average woman puts 115 ingredients on her skin—before lunch. That’s a lot.” It’s also helpful to use microbiome-friendly formulas, like Solvasa’s microbiome skincare, that’s gentle and nourishing, rather than stripping or aggressive. “The other way to encourage diversity is to simply go outside,” says Dr. Varma. “Play a sport, go for a walk or a run, garden, interact with nature. That’s good for you—and your skin’s microbiome.”

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What exactly is a prebiotic, probiotic…and a postbiotic? 

Most of us are familiar with probiotics; they are the good bacteria found in yogurt and fermented foods like sauerkraut and kefir that help improve the good-to-bad bacteria ratio in a microbiome. Prebiotics are substances probiotics feed on to get healthy and reproduce. “One way of encouraging good bacteria to grow is to add prebiotics to a microbiome,” explains Dr.Varma. And when bacteria are eating a prebiotic, it gives off molecules and proteins that provide a benefit. Those are postbiotics. 

With the growing understanding of this invisible universe that lives on our skin and its symbiotic role in supporting resilience to inflammatory stress, Solvasa is committed to providing formulations that support a healthy and diverse microbiome. This involves avoiding materials that destroy healthy bacteria and including pre- and post- biotic ingredients that support skin’s natural healthy state. 

Want more information from Dr. Varma on the skin’s microbiome? Check out Episode 6: The Invisible Truth on The Beauty Construct podcast, now available for download on Spotify or Apple Podcasts

Dr. Varma is the cofounder and CEO of Phyla and Phi Therapeutics, a microbiome company based in San Francisco. Dr. Varma is a trained microbiologist and synthetic biologist with a background in organic chemistry.