What Is the Gut-Skin Axis? A Simple Guide to How Your Gut May Affect Y

You only have to look at your skin after a week of broken sleep, missed meals and back-to-back stress, and you can see that something's out of balance. And you wouldn’t be wrong. Scientists now recognise a genuine biological connection between your digestive system and your skin, known as the gut-skin axis. It describes how the trillions of bacteria and other microbes living in your digestive tract, collectively known as the gut microbiome, may influence how your skin looks and behaves.¹

How Are the Gut and Skin Connected?

Although your gut and skin seem unrelated, they are in constant communication. Signals pass between them through the immune system, hormones and various inflammatory pathways. A balanced gut microbiome appears to help regulate these systems and support a healthy immune response. When that balance is disrupted, a state known as dysbiosis, inflammatory signals may increase and potentially influence skin health.²

This is part of why skin concerns such as acne, eczema and rosacea are increasingly discussed alongside gut health, even though the relationship is still being explored.³

The Role of the Gut Microbiome

Although the gut microbiome is best known for its role in digestion, its influence extends much further. The microbes living in your gut are involved in a range of processes that help support overall health, many of which may also have an indirect impact on your skin. Beyond digestion, your gut microbiome:

Supports nutrient absorption
Helps regulate immune function
Produces short-chain fatty acids. These compounds help nourish the cells lining the gut and may also influence immune function and inflammation throughout the body.

When any of these functions falter, the effects can indirectly affect skin health. Poor nutrient absorption, for example, may limit the availability of nutrients your skin relies on for structure and repair, such as zinc or essential fatty acids.⁴

What Can Influence the Gut-Skin Axis?

Like most aspects of health, the gut-skin axis is influenced by everyday lifestyle habits rather than any single factor. The choices we make each day can affect both the diversity of our gut microbiome and the way our skin functions. Some of the most important influences include:

Diet, particularly fibre intake and the variety of plant foods you eat
Stress levels, which affect both gut function and inflammation
Sleep quality
Antibiotic use and certain other medications

A varied, nutrient-rich diet that includes plenty of fibre and a wide range of plant foods, alongside fermented foods where appropriate, may help support a more diverse gut microbiome. However, individual responses can vary considerably depending on factors such as age, genetics, medication use and overall health.⁵

While the gut-skin axis is now well recognised, researchers are still trying to understand exactly how much it contributes to different skin conditions. Some links are supported by stronger evidence than others.

Current Research: What the Evidence Shows for Specific Skin Conditions

Research linking the gut to particular skin conditions has moved quickly over the past two years. Here is where the evidence currently stands for three of the most studied conditions.

Acne

Several studies published in 2024 and 2025 have used Mendelian randomisation, a method that draws on genetic data to test for cause and effect, to examine gut bacteria and acne risk. This research has linked certain bacterial groups, including Bifidobacterium, to acne development.

These findings suggest the gut microbiome may play an active, modifiable role rather than simply reflecting changes already taking place in the skin.⁶

A 2025 clinical trial also found that an eight-week oral synbiotic supplement shifted gut bacteria and short-chain fatty acid levels alongside a significant reduction in acne lesion counts, offering early clinical support for the connection.⁷

Eczema and Atopic Dermatitis

Atopic dermatitis has some of the strongest gut-skin research behind it so far. A 2025 review of trials conducted between 2018 and 2025 found that multi-strain probiotic formulations, particularly those combining Lactobacillus and Bifidobacterium strains, reported modest but reasonably consistent improvements in eczema severity and itch in children.⁸

Separate reviews of topical probiotic formulations have reported similar reductions in severity scores in adults, although researchers note that study sizes remain small and strains vary widely between trials, which makes direct comparisons difficult.⁹

Rosacea

The rosacea research tells a more cautious story. Several studies have found that people with rosacea are more likely to have small intestinal bacterial overgrowth, known as SIBO, and one widely cited trial found that eradicating the overgrowth led to significant improvement in rosacea lesions.¹⁰

A 2025 systematic review and meta-analysis confirmed a higher prevalence of SIBO among rosacea patients, but noted that testing methods vary between studies and results aren't always consistent.¹¹

Because of this, professional bodies have advised against SIBO screening as standard practice for rosacea until larger, more rigorous trials confirm the benefit, a useful reminder that gut-skin findings often travel faster in headlines than in clinical guidelines.¹²

Condition	Current Evidence
Acne	Growing evidence suggests gut bacteria may influence acne risk. Early trials of synbiotics have shown promising results.
Eczema / atopic dermatitis	The strongest evidence so far. Multi-strain probiotics have shown modest improvements in severity and itching, particularly in children.
Rosacea	An association with SIBO exists, but routine testing isn't currently recommended because evidence remains inconsistent.

Can Supporting Gut Health Improve Skin?

As the research above shows, some connections currently have firmer evidence behind them than others. Eczema and acne have the more established clinical data, while rosacea's gut link, though promising, still needs larger trials before firm conclusions can be drawn.

Although no diet or supplement can guarantee clearer skin, supporting overall gut health is a sensible approach with benefits that extend well beyond the skin. Eating a varied, fibre-rich diet, including fermented foods where appropriate, getting enough sleep and managing stress all help support a diverse and resilient gut microbiome.⁵

The Bigger Picture Behind Your Complexion

The gut-skin axis reminds us that healthy skin isn't just about what we put on it. Our digestive system, immune function, diet and lifestyle all interact in complex ways that researchers are only beginning to fully understand. While gut health won't explain every skin concern, looking after your microbiome may be one more piece of the puzzle that helps support healthier skin from within.

Written by: Jacqueline Newson BSc (Hons) Nutritional Therapy

References

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