The Gut-Skin Axis: Can Your Gut Microbiome Affect Your Skin?

Your skin is acting up.

Naturally, the investigation begins.

New skincare product?

Stress?

Hormones?

Allergies?

That serum you definitely didn't need but TikTok convinced you to buy at 11:47 p.m.?

All reasonable suspects.

But researchers are increasingly investigating another one:

Your gut.

A growing body of research suggests that the trillions of microorganisms living in your digestive tract may interact with your immune system in ways that are connected to what's happening on your skin.

Scientists call this relationship the gut-skin axis.

And a large systematic review examining 62 human studies looked at gut-microbiome patterns across three inflammatory skin conditions:

• Atopic dermatitis (eczema)

• Psoriasis

• Hidradenitis suppurativa

Researchers found recurring differences in the gut microbiomes of people with these conditions.

Interesting?

Very.

Proof that fixing your gut will fix your skin?

Not so fast.

The science is considerably more complicated.

Let's get into it.

What Is the Gut Microbiome?

Your digestive tract isn't just a food-processing tube.

It's an ecosystem.

Your gut contains a massive community of microorganisms—including bacteria, viruses, fungi, and other microbes—collectively referred to as the gut microbiota.

The gut microbiome generally refers to these microorganisms along with their genetic material and biological activity.

And they're busy.

Gut microbes can help:

• Break down components of food

• Produce certain vitamins and metabolites

• Interact with the immune system

• Maintain the intestinal environment

• Influence inflammation

• Support the gut barrier

Your microbiome begins developing very early in life and continues changing as you grow.

And even in adulthood, it's not set in stone.

Diet, medications, antibiotics, illness, environment, and other factors can all influence its composition.

Basically, your gut has an entire microscopic neighborhood living inside it.

And everyone appears to be talking.

What Is the Gut-Skin Axis?

The gut-skin axis describes the proposed two-way communication between the gut, its microorganisms, the immune system, and the skin.

And no, your intestines aren't texting your forehead.

The communication is chemical.

Researchers believe several interconnected systems may be involved, including:

The immune system.

Microbial metabolites.

Hormonal signaling.

The nervous system.

The intestinal barrier.

Gut microbes produce compounds that can interact with immune cells and potentially influence tissues far beyond the digestive tract.

Which brings us to one particularly interesting group of molecules.

Your Gut Bacteria Are Tiny Chemical Factories

Feed certain gut bacteria fermentable carbohydrates, including dietary fiber, and they can produce short-chain fatty acids, or SCFAs.

The major SCFAs include:

• Acetate

• Propionate

• Butyrate

These molecules don't just sit around waiting for someone to write a wellness blog about them.

They have actual jobs.

SCFAs can help influence:

• Intestinal barrier function

• Immune regulation

• Inflammatory signaling

• Metabolism

Some microbial metabolites can also enter circulation, creating potential pathways for the gut microbiome to influence other organs.

Including the skin.

Think of your microbiome less like a passive collection of bacteria and more like a chemical factory whose products can interact with your body.

And what you feed the factory matters.

What Is Gut Dysbiosis?

You'll see the word dysbiosis everywhere in microbiome research.

It generally refers to an altered microbial community that may be associated with disease or disrupted biological function.

But there's an important catch:

There isn't one universally perfect microbiome.

Having more of bacterium X and less of bacterium Y doesn't automatically mean your gut is “unhealthy.”

Microbiomes vary enormously between people.

So when researchers say a disease is associated with gut dysbiosis, they're generally describing patterns or changes in the microbial ecosystem—not diagnosing your gut as good or bad.

That's especially important when talking about skin disease.

Because researchers are finding associations.

Not a universal microbial fingerprint.

Eczema and Gut Health: Is There a Connection?

Atopic dermatitis, commonly called eczema, is a chronic inflammatory skin condition characterized by itching, dryness, and recurring inflammation.

And among the skin conditions studied through the gut-skin axis, eczema has received considerable attention.

Researchers have reported differences in the gut microbiomes of people with atopic dermatitis compared with people without it.

Some studies have found changes involving:

• Overall microbial diversity

• Bifidobacterium

• Lactobacillus

• Faecalibacterium prausnitzii

• Other bacteria involved in short-chain fatty acid metabolism

But the findings aren't perfectly consistent across every study.

That's important.

The takeaway isn't:

Low Bifidobacterium = eczema.

It's that atopic dermatitis appears to be associated with alterations in the broader gut microbial ecosystem in at least some populations.

Why Does Butyrate Keep Showing Up?

One particularly interesting area involves butyrate-producing bacteria.

Butyrate is a short-chain fatty acid produced when certain gut microbes ferment dietary substrates.

It's an important energy source for cells lining the colon and plays roles in intestinal barrier function and immune regulation.

Some studies of inflammatory skin disease have reported lower abundance of bacteria associated with butyrate production, including Faecalibacterium prausnitzii.

That creates an intriguing hypothesis:

Changes in gut bacteria could alter microbial metabolites, which could then influence immune signaling elsewhere in the body.

Potentially including the skin.

But—and this is a big but—

Finding fewer butyrate-associated bacteria doesn't automatically prove someone has less butyrate.

And it definitely doesn't prove that taking a butyrate supplement would treat eczema.

Microbiome association ≠ treatment recommendation.

We'll be using that sentence a lot.

Psoriasis and the Gut Microbiome

Psoriasis is another chronic inflammatory skin disease, driven in part by dysregulated immune pathways.

Research has also identified differences between the gut microbiomes of people with psoriasis and those of healthy comparison groups.

Some studies have reported changes involving microbes such as:

• Akkermansia muciniphila

• Faecalibacterium prausnitzii

• Other bacterial groups involved in immune and metabolic signaling

Changes in overall microbial diversity have also been reported.

But here's another place where I'd pump the brakes on a popular microbiome shortcut:

What About the Firmicutes-to-Bacteroidetes Ratio?

You've probably seen this ratio presented online like it's your microbiome's credit score.

High = bad.

Low = good.

Fix the ratio and everything is wonderful.

Unfortunately, biology did not make things that convenient.

Although changes in the relative abundance of major bacterial groups have been reported in microbiome studies, the Firmicutes-to-Bacteroidetes ratio is not a validated universal marker of gut health or psoriasis.

Different studies can produce different findings depending on the population, diet, medications, sequencing methods, geography, and dozens of other variables.

So we're not grading your gut microbiome with a calculator.

Not yet.

Hidradenitis Suppurativa and Gut Health

Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease that can cause painful nodules, abscesses, tunnels beneath the skin, and scarring—often in areas where skin rubs together.

Compared with eczema and psoriasis, research examining the gut microbiome in HS is still relatively limited.

But investigators have reported microbial differences in some studies, including changes in diversity and specific bacterial groups.

One organism of interest is Ruminococcus gnavus, which has also been studied in other inflammatory conditions.

Again:

Association.

Not proof that the bacterium causes HS.

And definitely not a reason to wage war against one species based on a consumer microbiome test.

The ecosystem matters more than a single microbial villain.

Is There One “Inflammatory Skin Microbiome”?

Probably not.

This is where the research gets more interesting—and more frustrating.

Across eczema, psoriasis, and hidradenitis suppurativa, researchers have reported recurring themes such as:

• Altered microbial diversity

• Changes in SCFA-associated bacteria

• Differences in potentially beneficial microbes

• Changes in organisms associated with inflammatory states

That suggests there may be shared biological pathways connecting the gut microbiome, immune regulation, and inflammatory skin disease.

But researchers haven't identified one universal:

“This is what the gut microbiome of someone with inflammatory skin disease looks like.”

And that's probably because there isn't one.

Your microbiome is influenced by your:

diet,

age,

genetics,

medications,

geography,

environment,

disease state,

and probably whatever microbial chaos happened during last week's antibiotic prescription.

Microbiome science is messy.

That's also why it's interesting.

Can Skin Inflammation Affect Your Gut Too?

Here's the plot twist.

We've been talking about:

Gut → skin

But the gut-skin axis may be bidirectional.

Inflammatory disease itself—and potentially the treatments used for it—could influence the microbiome.

Some research has found microbiome changes after treatment for inflammatory skin disease.

That raises an important chicken-or-egg question:

Did gut dysbiosis contribute to the skin disease?

Did the skin disease and systemic inflammation alter the gut microbiome?

Did medication change both?

Or are all of these processes interacting?

The current answer is basically:

Yes, potentially.

Welcome back to biology.

Can Probiotics Improve Your Skin?

Naturally, this is where everyone's mind goes.

If gut bacteria are associated with skin health…

Should we just take probiotics?

Maybe someday we'll have much better answers.

Right now, it's complicated.

Probiotics are not one intervention.

Different products contain different:

• Species

• Strains

• Doses

• Combinations

And different strains can have very different biological effects.

Research into probiotics and inflammatory skin conditions is ongoing, with some promising findings in particular populations and formulations.

But the evidence isn't strong enough to say:

“Take a probiotic and your eczema or psoriasis will improve.”

That's especially true because microbiome patterns vary considerably between individuals.

The future may be more targeted than grabbing the bottle with the largest number of CFUs at the grocery store.

Can Diet Affect the Gut-Skin Axis?

This is another area researchers are actively exploring.

Diet is one of the major factors capable of influencing the gut microbiome.

Foods rich in fermentable fibers and plant compounds can provide substrates that certain microbes metabolize into compounds such as SCFAs.

That means researchers are interested in whether dietary patterns could potentially influence inflammatory pathways through the microbiome.

But again, don't turn this into:

Eat more fiber → cure psoriasis.

That's not what the evidence says.

A varied diet containing fruits, vegetables, legumes, whole grains, nuts, seeds, and other fiber-rich foods can support overall health and provide substrates for gut microbes.

Whether specific dietary interventions can meaningfully treat particular inflammatory skin diseases through the gut microbiome requires much more research.

Your salad is doing chemistry.

It's just not a prescription.

Could We Eventually Test the Gut to Understand the Skin?

Possibly.

This may be one of the most exciting areas of microbiome research.

Researchers are investigating whether combinations of:

• Microbial species

• Microbial genes

• Metabolites

• Immune markers

• Clinical information

could eventually help identify disease patterns or predict treatment responses.

Artificial intelligence and machine learning may help because microbiome datasets are enormous and complicated.

The long-term vision is something closer to:

Your microbiome profile + your immune markers + your clinical history → more personalized treatment.

Very cool.

Also very much a work in progress.

Consumer microbiome testing is not currently a replacement for established diagnostic testing or evaluation by a healthcare professional.

Your poop sample isn't your dermatologist.

Yet.

So Does Gut Health Affect Your Skin?

Probably in some ways.

But we need to be precise about what that means.

The gut microbiome communicates extensively with the immune system and produces metabolites capable of influencing biology throughout the body.

Human studies have also found differences in gut microbial communities among people with several inflammatory skin diseases.

Together, that provides a biologically plausible gut-skin connection.

What we don't yet know is exactly how much those microbial changes contribute to causing disease, which changes matter most, or whether intentionally modifying them will reliably improve skin conditions.

That's the gap researchers are now trying to close.

What Can You Actually Do for a Healthy Gut and Skin?

This is where we'd love to give you a secret microbiome protocol.

We don't have one.

But we do have some decidedly unsexy health advice.

Eat a varied, nutrient-dense diet.

Get enough dietary fiber.

Regularly eat a variety of plant foods.

Exercise.

Get adequate sleep.

Avoid unnecessary antibiotic use.

Don't smoke.

Manage chronic health conditions.

And if you have eczema, psoriasis, hidradenitis suppurativa, or another persistent inflammatory skin condition, don't replace evidence-based treatment with a DIY “gut healing” protocol.

Your microbiome may be part of the picture.

It isn't necessarily the entire painting.

The Bottom Line

Your gut and skin aren't two completely separate worlds.

They're part of the same biological system.

Gut microbes interact with the immune system, produce metabolites such as short-chain fatty acids, influence intestinal barrier function, and may send biological signals far beyond the digestive tract.

Meanwhile, studies of people with eczema, psoriasis, and hidradenitis suppurativa have identified differences in gut microbial communities compared with people without these conditions.

That's why the gut-skin axis has become such an interesting area of research.

But we're not at:

“Fix your gut, fix your skin.”

Not even close.

Researchers still need to figure out whether particular microbiome changes help drive inflammatory skin disease, result from the disease, or both—and whether

_References:

_{Malgesini A, Marsiglia MD, Borghi E, Marzano AV, Nazzaro G. The Emerging Role of Gut Microbiota in Inflammatory Skin Diseases: A Systematic Review. Exp Dermatol. 2026 Mar;35(3):e70234. doi: 10.1111/exd.70234. PMID: 41795861; PMCID: PMC12967704.}