Gut Health and Acne: Understanding the Gut–Skin Axis

By Lucy Sugars, Nutritional Therapist

f you have acne, you may have come across the idea that you need to “heal your gut” to clear your skin.

There is growing scientific interest in the relationship between the gut and skin, often referred to as the gut–skin axis. Researchers are exploring how the gut microbiome, immune system, diet and skin may interact, and studies have identified differences in the gut microbiome of people with acne.

But this is an emerging area of research, and the relationship is much more complex than the idea that poor gut health simply causes acne.

So what do we actually know, and should gut health form part of the way we think about acne?

What is the Gut–Skin Axis?

The gut is home to trillions of microorganisms, collectively known as the gut microbiome.

These microorganisms interact with our immune system, help metabolise components of our diet and produce compounds that can influence processes elsewhere in the body.

The skin also has its own microbiome, and researchers are increasingly interested in communication between the gut, immune system and skin. This relationship has become known as the gut–skin axis.

Research has explored the gut microbiome in several inflammatory skin conditions, including acne, eczema, psoriasis and rosacea.

However, identifying a relationship doesn’t necessarily tell us what is causing what.

What Does the Research Say About Gut Health and Acne?

Some studies have found differences in the composition and diversity of the gut microbiome in people with acne compared with people without acne.

This is interesting, but it doesn’t prove that changes in gut bacteria cause acne.

Many factors can influence the gut microbiome, including diet, medications such as antibiotics, age, environment and lifestyle. Some of these factors may also be relevant to acne.

Researchers are therefore still trying to understand whether microbiome differences contribute to acne, occur alongside it, or reflect other differences between people with and without acne.

At present, we don’t have enough evidence to treat manipulation of the gut microbiome as a standard acne treatment.

What About Altered Intestinal Permeability?

The intestinal lining forms an important barrier between the contents of the digestive tract and the rest of the body. When the integrity of this barrier is altered, intestinal permeability can increase, potentially allowing microbial products and other substances to interact more readily with the immune system.

Altered intestinal permeability has been investigated in a range of inflammatory and metabolic conditions, and there is growing interest in whether changes to the gut barrier may also form part of the gut–skin relationship.

Some emerging research has identified changes in intestinal permeability and markers associated with gut barrier function in people with acne. However, this is still a developing area and we cannot yet say that increased intestinal permeability causes acne or that “repairing the gut lining” will clear the skin.

In practice, I think it is reasonable to consider gut health as one potential part of the wider picture, particularly where someone has significant digestive symptoms alongside their skin concerns. This is different from assuming that everyone with acne has a “leaky gut” or needs a gut-healing protocol.

What About Constipation?

Constipation doesn’t directly cause acne, and I wouldn’t describe it as causing “toxins” to build up and escape through the skin. However, bowel function can still be relevant when considering someone’s wider digestive and hormonal health.

Slower intestinal transit can influence the gut microbial environment and has been associated with changes in microbiome composition. Gut bacteria also produce enzymes such as beta-glucuronidase, which can deconjugate compounds that have been processed by the liver, including oestrogens, potentially allowing some to be reabsorbed through the intestine.

This has led to growing interest in the relationship between the gut microbiome, bowel transit and oestrogen metabolism, sometimes referred to as the estrobolome. However, the clinical significance of this in relation to acne is not yet well established.

For someone experiencing both constipation and acne, I would therefore consider bowel function as part of their overall health picture rather than assuming it is the cause of their breakouts.

Supporting regular bowel movements through adequate fibre, fluids, movement and a varied diet is beneficial for digestive health in its own right. Persistent or unexplained constipation should also be appropriately investigated rather than simply treated as a skin issue.

Supporting Gut Health

While we can’t say that improving gut health will clear acne, supporting a healthy gut environment can form part of a broader nutritional approach, particularly where digestive symptoms are also present.

Rather than relying on restrictive diets or complicated “gut healing” protocols, I generally start with the foundations: a varied diet, plenty of fibre and plant foods, adequate fluids and regular bowel movements.

Eat a Variety of Plant Foods

Different plant foods provide different types of fibre and plant compounds that can support a diverse gut microbiome.

Try to include a mixture of:

Vegetables and fruit
Beans, lentils and chickpeas
Wholegrains
Nuts and seeds
Herbs and spices

Variety matters more than chasing a particular number. Regularly rotating the plants you eat is a simple way of providing different fibres and polyphenols for your gut bacteria.

Include Plenty of Fibre

Dietary fibre supports normal bowel function and provides substrates that gut bacteria can ferment to produce compounds such as short-chain fatty acids, including butyrate.

Short-chain fatty acids have a number of roles within the gut, including helping to support the intestinal barrier and interacting with the immune system. This is one of the reasons a fibre-rich diet may be relevant when thinking about both microbiome and gut-barrier health.

Useful sources include oats, wholegrain bread, beans, lentils, chickpeas, fruit, vegetables, nuts and seeds.

If your diet is currently relatively low in fibre, increase it gradually and make sure you’re drinking enough alongside it.

Include Fermented Foods if You Enjoy Them

Fermented foods such as live yoghurt, kefir, sauerkraut and kimchi can provide live microorganisms and may help support microbial diversity as part of a varied diet.

They aren’t an acne treatment, and they won’t suit everybody, particularly those with certain digestive symptoms. But where they’re well tolerated, they can be a useful addition rather than something that needs to be taken in supplement form.

Support Regular Bowel Function

Given the relationship between intestinal transit, the microbiome and the metabolism of compounds within the gut, I also pay attention to bowel regularity rather than treating constipation as unrelated to someone’s wider nutritional picture.

Adequate fibre and fluids, regular movement and eating enough food all help support normal bowel function.

If constipation is persistent, new or accompanied by pain, bleeding, unexplained weight loss or other concerning symptoms, it should be medically investigated.

What About Probiotics?

There is growing research into the potential role of probiotics in acne, including their possible effects on the gut microbiome, intestinal barrier and inflammatory signalling.

Some early studies have reported improvements in acne outcomes when particular probiotics have been used, but the evidence is still limited and we don’t yet have enough high-quality research to recommend probiotics as a standard acne treatment.

It’s also important to remember that probiotics are strain-specific. Different species and strains can have very different effects, so choosing a product simply because it contains a high number of bacteria or is marketed for “gut health” isn’t necessarily helpful.

I therefore wouldn’t suggest that everyone with acne needs a probiotic. Where digestive symptoms or other indications are present, it may be something to consider individually alongside diet and wider health.

What About Gut Testing?

Gut and stool testing is an area where I think context matters.

Conventional stool testing has an important role in investigating particular gastrointestinal symptoms, infections and inflammatory conditions. More comprehensive functional or microbiome tests can also provide information about microbial composition, digestive markers and, depending on the test, markers such as beta-glucuronidase.

However, our understanding of the microbiome is still developing. There is no single definition of an “optimal” microbiome, and identifying a particular bacterial pattern or an out-of-range marker doesn’t necessarily establish that it is causing someone’s acne.

I therefore wouldn’t routinely recommend comprehensive stool testing simply because someone has acne.

Where significant or persistent digestive symptoms exist alongside skin concerns, further investigation may sometimes be appropriate, but results need to be interpreted within the context of the person’s symptoms, diet, medical history and wider clinical picture rather than treated as a standalone explanation for their skin.

The Bigger Acne Picture

Acne is multifactorial, and gut health may be one piece of that picture for some people rather than the explanation for everyone.

When considering nutrition alongside acne, I look at the wider pattern. Depending on the individual, this might include:

Overall diet quality and variety
Blood sugar balance and glycaemic load
Individual food triggers
Digestive symptoms and bowel function
Hormonal influences
Stress and sleep
Skincare and topical products
Medications
Wider health and symptom history

Not every factor will be relevant to every person, which is why I prefer an individual approach rather than assuming everyone with acne needs the same restrictive diet, supplement protocol or gut intervention.

Nutrition can also sit alongside appropriate skincare and medical treatment rather than replacing them.

The Bottom Line

The gut–skin axis is a genuine and fascinating area of research, and our understanding of the relationship between the gut microbiome, intestinal barrier, immune system and skin continues to develop.

There is evidence of differences in the gut microbiome in people with acne, while altered intestinal permeability, microbial metabolites and inflammatory signalling are all being explored as possible parts of the relationship.

What we can’t yet say is that gut dysfunction causes acne or that “healing the gut” will clear someone’s skin.

For me, the sensible middle ground is to take digestive health seriously without making it responsible for every breakout.

A varied, fibre-rich diet, adequate fluids, regular bowel function and appropriate attention to persistent digestive symptoms provide a good foundation. Where gut symptoms and acne occur together, it can also be reasonable to consider them as part of the same wider health picture while recognising that the relationship may differ considerably between individuals.

If you would like personalised nutrition support that considers your skin alongside your digestive health, diet and wider health picture, you can find out more about my approach on the Bespoke Nutrition page.