People with acne tend to have a different mix of gut bacteria from people with clear skin. Research so far suggests a possible relationship between gut health and acne, not a proven cause. The studies behind that finding are small, they measured people at a single point in time, and none of them can say whether the gut differences help cause acne, result from it, or come from something else, such as diet, that affects both. Acne itself is driven by hormones, excess sebum (the skin's natural oil), blocked pores and a skin bacterium called Cutibacterium acnes, and nothing found in the gut changes that. This guide covers what has been measured in the gut in people with acne, how gut bacteria could plausibly reach the skin, where diet fits, what trials of probiotics have found, and what a gut microbiome test can and cannot tell you. The wider connection between the two organs is covered in our guide to the gut-skin axis.
Is acne linked to changes in gut bacteria?
In a 2018 study, researchers sequenced stool samples from 43 people with acne and 43 people without. The acne group had a less varied mix of gut bacteria overall, and the groups most depleted included Lachnospiraceae and Ruminococcaceae, families of fibre-fermenting bacteria generally regarded as beneficial.
A second study the same year compared 31 people with moderate to severe acne against 31 without. It found lower levels of several familiar groups in the acne patients, including Bifidobacterium and Lactobacillus, the two types most often sold as supplements.
Variety is the measure to watch in those findings. Different gut bacteria do different jobs, so a broad mix covers more of the work of fermenting fibre, making useful compounds and keeping less helpful species in check. Reduced variety keeps appearing as a marker across gut research well beyond skin studies, which makes it the least surprising and best supported part of the acne findings.
The pattern has held in more recent work. A small 2026 pilot study of 17 people with moderate to severe acne and 14 without found the acne group had a markedly less diverse gut microbiome, and the differences in the gut were more pronounced than the differences on the skin itself.
These are small studies. Each one measured people once, so they show a difference, not a direction. People with acne may also eat differently, take different medicines, or differ in other ways a one-off comparison cannot fully separate out.
How might the gut microbiome influence acne?
A 2018 review in Frontiers in Microbiology set out the main routes. A large share of the body's immune cells sit in and around the gut, so the bacteria living there help set the tone of immune responses across the whole body, including in the skin. Gut bacteria also make compounds that travel beyond the gut. Short-chain fatty acids, which gut bacteria produce when they break down fibre, help keep inflammation in balance. And when the gut lining becomes more permeable, bacterial fragments can pass into the bloodstream and add to low-grade inflammation around the body.
Every route in that list is better evidenced in the gut than in the skin. The clearest human version of the connection is in eczema, where gut differences appear in infancy, sometimes before any symptoms do; our guide to gut health and eczema covers that evidence. For acne, the mechanisms are plausible and partly demonstrated, but the chain from a specific gut change to a specific spot has not been traced in people.
Can diet affect both gut health and acne?
Diet is where the trial evidence is strongest. In a 12-week Australian trial, 43 young men with acne were randomly assigned to a low glycaemic load diet, built around foods that release sugar slowly, or to a carbohydrate-heavy control diet. The low glycaemic group finished with significantly fewer acne lesions and better insulin sensitivity. A Korean trial of 32 people found the same pattern over 10 weeks, and skin samples showed smaller sebaceous glands and less inflammation in the low glycaemic group.
The leading explanation runs through insulin. Meals that push blood sugar up quickly raise insulin and a related growth signal called IGF-1, and both push the skin to produce more sebum. The same dietary pattern also changes which gut bacteria thrive, which is why the gut keeps appearing in this research. A 2024 review of diet and acne sets out both strands. One caution applies to the trials. They were small, and in the Australian one the low glycaemic group also lost weight, which could explain part of the improvement.
The dairy evidence is weaker than it often sounds online. A meta-analysis pooling data from more than 78,000 children, teenagers and young adults found that those who consumed dairy were somewhat more likely to have acne, with milk showing the clearest pattern. Every included study was observational, so the result is an association rather than proof of cause, and the authors found signs that studies with positive results were more likely to have been published. No trial has removed dairy and measured what happens to acne.
UK guidance reflects how early this evidence is. The NICE guideline on acne, which shapes how acne is treated in the NHS, does not recommend any particular diet as a treatment, and a GP will reach for proven options first.
None of this is a reason to cut out food groups on your own. Dairy carries calcium, iodine and protein, and unsupervised elimination diets cause real nutritional problems, particularly for teenagers, the group most likely to have acne. If you want to test a dietary change, do it with your GP or a registered dietitian guiding it.
Do probiotics help acne?
Researchers have tested whether supplements containing live bacteria, usually Lactobacillus and Bifidobacterium species, change acne. A 2025 meta-analysis pooled nine randomised trials covering 623 people. After four weeks there was little difference between the supplement and placebo groups. After twelve weeks, the supplement groups showed lower acne severity and fewer lesions, both inflamed spots and blocked pores, with no serious side effects reported. The pooled trials tested particular species and doses, so the result belongs to the products studied rather than to every supplement sold as a probiotic. Twelve weeks is longer than most people give a supplement, which may explain why individual experiences and trial results often disagree.
An earlier Canadian trial points the same way. Forty-five women with mild to moderate acne were assigned to a probiotic, to the antibiotic minocycline, or to both. All three groups improved, and the group taking both improved most. The trial was open label, meaning everyone knew what they were taking, which weakens the result.
A 2025 UK review of microbiome-based approaches to acne concluded that most of the research so far is small, much of it was done in the laboratory or in animals, and the trials used different species, doses and durations, so it is not yet possible to say which bacteria matter or for whom. No supplement is licensed to treat acne in the UK, and nothing in this research replaces standard acne treatment.
How do acne antibiotics affect gut health?
Oral antibiotics are a standard treatment for moderate inflammatory acne, and courses typically run for weeks to months rather than days. Antibiotics do not distinguish between the bacteria they are prescribed against and the bacteria living in your gut, so a long course changes the gut microbiome while it works on the skin. Our guide to what antibiotics do to the gut microbiome covers what changes and how the gut recovers afterwards.
None of that is a reason to avoid them. Antibiotics for acne are prescribed because they work, untreated inflammatory acne can scar permanently, and stopping a course early creates problems of its own, including antibiotic resistance. If you are partway through a course and have questions about your gut, ask the prescriber or a pharmacist rather than stopping.
What can a gut microbiome test tell you about acne?
A stool-based gut microbiome test measures which bacteria are living in your gut, how varied the mix is, and whether groups that research has linked with skin conditions are present at low levels. Set against the studies above, that means you can see whether your own gut shows the kind of pattern, reduced variety or low levels of fibre-fermenting bacteria, that studies have reported in people with acne.
Our test does that by sequencing the bacterial DNA in a stool sample and comparing your profile against published research involving people with and without skin conditions, so the report can show whether your results share features with the patterns those studies describe. It reports similarity to a research pattern, never a diagnosis.
The limits matter as much as the information. A gut test cannot diagnose acne, it cannot tell you that your gut is causing your skin problems, and it cannot promise that changing your gut will change your skin, because the research itself cannot yet show any of those things. What it gives you is a measurement of the gut side of the picture, which is otherwise invisible. If acne is the reason you are looking at your gut, gut microbiome testing for acne explains what our test measures and reports for skin.
Can improving gut health help with acne?
No study has shown that changing your gut bacteria clears acne. The evidence comes in three kinds, and they carry different weight. Comparisons of gut bacteria in people with and without acne show differences, not causes. Mechanism research shows how the gut could influence the skin, much of it from the laboratory. And the small number of human trials, of diet and of supplements, improved acne without establishing that the gut carried the effect.
The direction of the link is unresolved. The gut differences found in people with acne could contribute to the condition, result from it, or reflect diet and lifestyle acting on both at once. The existing studies are snapshots and cannot separate those possibilities.
The field is young. The core human evidence amounts to a few hundred people across a handful of small studies, and findings at this scale sometimes do not repeat when larger studies are run. Anyone selling a gut-based cure for acne is ahead of what the research can support.
When should you see a GP about acne?
A GP can do more for acne than many people expect, from prescription creams to referral to a dermatologist. See your GP if your acne is severe, with large painful lumps or cysts under the skin, if it is leaving scars or dark marks, if pharmacy treatments have not helped after a couple of months, or if it is affecting your mood or how you feel about yourself, which NHS treatment takes seriously. See a GP promptly if acne appears alongside irregular periods or excess facial or body hair, which can point to polycystic ovary syndrome, or if severe acne starts suddenly with fever or joint pain, which needs urgent assessment. No gut test and no dietary change replaces that assessment, and nobody should stop a prescribed acne treatment on the strength of gut research.
This guide is for information only and does not replace medical advice. Speak to your GP or pharmacist about your own symptoms.
Sources
- Deng Y, Wang H, Zhou J, et al. (2018). Patients with Acne Vulgaris Have a Distinct Gut Microbiota in Comparison with Healthy Controls. Acta Dermato-Venereologica. PubMed | DOI
- Yan HM, Zhao HJ, Guo DY, et al. (2018). Gut microbiota alterations in moderate to severe acne vulgaris patients. The Journal of Dermatology. PubMed | DOI
- Lesiak A, Krawczyk A, Piasta J, et al. (2026). Gut and skin dysbiosis in acne vulgaris: a comparative microbiome analysis. Frontiers in Cellular and Infection Microbiology. PubMed | DOI
- Salem I, Ramser A, Isham N, Ghannoum MA (2018). The Gut Microbiome as a Major Regulator of the Gut-Skin Axis. Frontiers in Microbiology. PubMed | DOI
- Smith RN, Mann NJ, Braue A, et al. (2007). A low-glycemic-load diet improves symptoms in acne vulgaris patients: a randomized controlled trial. The American Journal of Clinical Nutrition. PubMed | DOI
- Kwon HH, Yoon JY, Hong JS, et al. (2012). Clinical and histological effect of a low glycaemic load diet in treatment of acne vulgaris in Korean patients: a randomized, controlled trial. Acta Dermato-Venereologica. PubMed | DOI
- Ryguła I, Pikiewicz W, Kaminiów K (2024). Impact of Diet and Nutrition in Patients with Acne Vulgaris. Nutrients. PubMed | DOI
- Juhl CR, Bergholdt HKM, Miller IM, et al. (2018). Dairy Intake and Acne Vulgaris: A Systematic Review and Meta-Analysis of 78,529 Children, Adolescents, and Young Adults. Nutrients. PubMed | DOI
- Lin HW, Tam KW, Huang YC (2025). Efficacy of oral probiotics in patients with acne: a systematic review and meta-analysis of randomized trials. Clinical and Experimental Dermatology. PubMed | DOI
- Jung GW, Tse JE, Guiha I, Rao J (2013). Prospective, randomized, open-label trial comparing the safety, efficacy, and tolerability of an acne treatment regimen with and without a probiotic supplement and minocycline in subjects with mild to moderate acne. Journal of Cutaneous Medicine and Surgery. PubMed | DOI
- Searle T, Al-Niaimi F, Ali FR (2025). Modulation of the microbiome: a paradigm shift in the treatment of acne. Clinical and Experimental Dermatology. PubMed | DOI
