Why Your Acne Won't Go Away (Hint: It Might Be Your Gut)

The gut-skin axis refers to the bidirectional communication between your gastrointestinal system and your skin. Just as the gut-brain axis describes how gut bacteria influence mood and neurological function, the gut-skin axis describes how conditions in the gut — particularly the state of the gut microbiome and gut barrier — can influence the health, appearance, and inflammatory status of the skin.

This connection operates through several pathways: the immune system (which is largely housed in and around the gut), the bloodstream, and the nervous system. When the gut is in a state of imbalance — whether through dysbiosis, increased intestinal permeability, or chronic low-grade inflammation — those conditions can manifest systemically, including in the skin. [1]

The reverse is also studied: the skin has its own microbiome, and there appears to be cross-talk between gut and skin microbial communities that researchers are only beginning to map. While this field is still evolving, the volume of research examining the gut-skin connection has grown significantly in recent years.

Your gut microbiome — the community of trillions of bacteria, fungi, and other microorganisms living in your digestive tract — plays a central role in regulating immune function, producing metabolites, and maintaining a healthy gut barrier. When this community becomes disrupted, a state known as gut dysbiosis, the downstream effects may extend well beyond the gut itself.

Some research suggests that people with acne show differences in gut microbial composition compared to those with clear skin — including lower levels of beneficial bacteria like Lactobacillus and Bifidobacterium, which are associated with immune regulation and anti-inflammatory activity. [2] When beneficial strains are depleted, and opportunistic bacteria overgrow, the gut's immune-modulating functions may be compromised, potentially contributing to the kind of systemic inflammation that drives acne.

It's worth noting that the direct causal relationship between gut dysbiosis and acne in humans is still being investigated. What the research does support clearly is that a balanced, diverse gut microbiome plays an important role in regulating immune and inflammatory activity — both of which are central to acne pathology.[3]

One mechanism researchers point to in the gut-skin connection is increased intestinal permeability, commonly called "leaky gut." Under normal conditions, the gut lining acts as a selective barrier — allowing nutrients into the bloodstream while blocking bacteria, toxins, and other particles from passing through. When tight junction proteins that hold intestinal cells together are disrupted, the gut barrier becomes more permeable. [4]

When bacteria-derived compounds like lipopolysaccharides (LPS) — fragments of bacterial cell walls — pass from the gut into the bloodstream through a compromised gut lining, they can activate immune responses and contribute to systemic inflammation. [5] Acne is fundamentally an inflammatory condition: while Cutibacterium acnes (formerly Propionibacterium acnes) plays a role in its development, it's the inflammatory response to that bacteria that causes the red, swollen, painful breakouts most people are trying to treat.

Research has shown that systemic inflammation can worsen acne and make it more resistant to treatment. If gut barrier dysfunction is contributing to a low-grade inflammatory state in the body, that background inflammation may make acne harder to manage with topical treatments alone. [4]

Small intestinal bacterial overgrowth (SIBO) — a condition in which bacteria proliferate in excessive numbers in the small intestine — has been associated in some studies with skin conditions including acne and rosacea. The proposed mechanism involves bacterial metabolites produced during SIBO traveling via the bloodstream and contributing to inflammatory processes that affect skin. [6]

This connection is still being actively studied, and not all people with acne have SIBO. But if you're experiencing both significant digestive symptoms (bloating, gas, irregular bowel habits) and persistent skin issues, it may be worth discussing with a healthcare provider whether SIBO could be a factor worth investigating.

The foods you eat don't just affect your gut — they affect your skin too, largely through the gut microbiome as an intermediary.

High-glycemic foods — refined carbohydrates, sugary drinks, white bread, processed snacks — cause rapid spikes in blood sugar and insulin levels, which in turn may increase sebum production and promote the inflammatory pathways involved in acne. These same foods also tend to negatively affect gut microbiome diversity.

Dietary fiber and fermented foods work in the opposite direction. A randomized trial published in Cell by researchers at Stanford found that a diet high in fermented foods significantly increased gut microbiome diversity and reduced markers of systemic inflammation — including inflammatory proteins that have been associated with conditions like acne. [7] A diet that supports a diverse, balanced microbiome may therefore support clearer skin through reduced systemic inflammation, even if the effect isn't immediate.

Dairy remains a debated topic in acne research. Some evidence suggests that whey-containing dairy products may influence acne through hormonal pathways — particularly IGF-1, or insulin-like growth factor 1 — though individual responses vary considerably.

For people interested in learning more about their own microbiome, the Jona Gut Microbiome Test offers at-home insight into gut bacteria and related health associations.

This is the question most people want answered directly — and the honest answer is: potentially, yes, for some people. But it's unlikely to be an instant or universal fix.

Probiotics are the most studied gut-targeted intervention in the context of acne. A completed clinical trial (NCT05919810) investigated the effects of oral probiotics alongside herbal supplementation on gut microbiome composition and sebum excretion rates in people with non-cystic acne. While clinical trials like this one are building the evidence base, the research on probiotics for acne is still developing, and no probiotic formulation has been established as a standard acne treatment. [8]

What the evidence does support more broadly is that supporting gut health — through diet, fiber, fermented foods, stress management, and potentially targeted probiotics — can reduce systemic inflammatory markers. For people whose acne is driven or worsened by systemic inflammation, this may make a meaningful difference over time.

Here's a practical starting point if you want to explore the gut-skin connection for yourself:

Keep a Food, Gut, and Skin Diary

Tracking what you eat, how your digestion feels, and how your skin responds over 2–4 weeks can reveal patterns. Many people notice connections between high-FODMAP foods, dairy, or high-sugar days and skin flares.

Address Gut Health Foundations First

Increasing fiber, eating more fermented foods, reducing processed foods and alcohol, and managing stress are well-supported strategies for improving gut health — and none of them come with downsides.

Talk to Your Healthcare Provider

If you have significant digestive symptoms alongside persistent acne, mentioning both to your provider opens the door to evaluating whether SIBO, food intolerances, or gut dysbiosis may be worth investigating. A dermatologist and a gastroenterologist working together can offer a more complete picture than either specialty alone.

Consider a Gut Microbiome Test

If you want to understand the actual state of your gut bacterial communities — diversity levels, beneficial bacteria presence, and signs of imbalance — at-home microbiome testing can give you data to work with rather than guesswork.

If you've been wondering whether your gut health may be connected to your skin, the Jona Gut Microbiome Test can give you a clearer picture of what's happening below the surface. It analyzes the full bacterial landscape of your gut from home — so you can see whether dysbiosis might be part of your skin story.

For people whose acne hasn't responded to conventional topical treatments, looking deeper — at the gut — may be a meaningful next step. The Jona Gut Microbiome Test, available through Everlywell, gives you a detailed, sequencing-based look at your gut's bacterial communities from home, with results processed by CLIA-certified laboratories. Understanding your gut microbiome is a foundational step toward addressing not just digestive symptoms, but the systemic conditions that may be affecting your skin.