What Emerging Research Is Beginning to Reveal
Why scientists are looking beyond the surface to understand skin health
Skin does not function in isolation. New research is tracing how gut microbes and their metabolites may influence immune activity, barrier function, mitochondrial metabolism and even the way skin cells handle lipids. Here is what the evidence can tell us now, and where the science is still unfolding.
Skin is not working alone
We often think of skin as something we treat only from the outside. We cleanse it, apply a serum and protect its barrier with a moisturiser. These steps matter, but the skin is also a living immune and metabolic organ connected to the rest of the body.
Scientists use the term gut-skin axis to describe communication between the intestinal microbiome, the immune system, microbial metabolites and the skin. It is not a direct pipeline from the stomach to the face, and it does not mean that every breakout, rash or sensitivity begins in the gut. It is a biological network that researchers are only beginning to map in detail.
An important distinction: an association between a microbiome pattern and a skin condition does not prove that one caused the other. The strongest emerging studies are now looking beyond lists of bacteria to the metabolites, immune signals and cellular pathways that may connect them.
What exactly is being communicated?
The gut contains trillions of microorganisms that help transform components of food, interact with bile acids and hormones, and produce bioactive compounds. The skin has its own site-specific microbiome and its own barrier ecosystem. Signals from the gut may reach the skin through the circulation, while immune, hormonal and nervous-system responses can influence both environments.
Among the most studied messengers are short-chain fatty acids, including acetate, propionate and butyrate, which are produced when certain gut microbes ferment dietary fibre. Researchers are also examining tryptophan-derived compounds, bile acids and microbial cell products. The effect depends on the compound, its concentration and the biological setting. A microbial metabolite is not automatically beneficial simply because it is natural.
Mitochondria may be part of the bridge
A 2022 experimental study found that butyrate supported skin-barrier integrity by altering mitochondrial metabolism in keratinocytes, the predominant cells in the epidermis. In a mouse model of allergy-related skin inflammation, fermentable fibre and short-chain fatty acids supported keratinocyte differentiation and the production of structural proteins and lipids needed for the outer barrier [1]. This is a compelling mechanism, but it remains preclinical research. It does not prove that a fibre supplement or butyrate product will treat eczema in people.
Barrier integrity and immune signalling
When the intestinal barrier is disturbed, microbial products and metabolites may enter the circulation more readily and influence systemic immune activity. The popular phrase 'leaky gut' is often used too loosely, so it is more accurate to talk about measured changes in intestinal permeability and specific barrier biomarkers.
In 2025, researchers compared 50 adults with atopic dermatitis with 25 controls. They found that several circulating gut-derived metabolites and intestinal-barrier biomarkers were associated with disease severity [2]. Because the study was observational and relatively small, it cannot show whether those changes caused the dermatitis, resulted from it or reflected another shared factor. Its value lies in identifying measurable signals for larger prospective studies.
The frontier is moving from bacteria to metabolites
One of the most important shifts in microbiome science is the move away from simply asking which bacteria are present. Researchers increasingly want to know what those microbes are producing and how those products change human cells.
A 2025 study in Immunity identified a gut-derived metabolite called indoxyl sulfate as a driver of psoriatic inflammation in experimental models. Gut-resident indole-producing microbes influenced this pathway, while the metabolite altered gene accessibility in skin Th17 immune cells through aryl hydrocarbon receptor signalling. Serum levels also correlated with disease severity in human psoriasis cohorts [3]. The mechanistic work was largely performed in mice, but it provides a more precise biological pathway than the general statement that 'dysbiosis causes inflammation.'
In May 2026, another psoriasis study examined bile acids, compounds produced by the liver and extensively modified by gut microbes. The researchers linked altered bile-acid profiles with signalling through the FXR receptor in keratinocytes, affecting antioxidant defences and lipid metabolism in the skin [4]. The human metabolite sample was very small and the functional experiments were preclinical, so this is hypothesis-generating rather than a treatment roadmap. It is nevertheless a striking example of how the field is connecting gut microbial chemistry to skin-cell metabolism.
Postbiotics and multi-omics
Another emerging direction is the study of postbiotics. These are preparations of inanimate microorganisms and/or their components, rather than live bacteria. In July 2026, researchers used metabolomics and gene-expression analysis to study probiotic-derived metabolite extracts in inflamed keratinocytes and dermal fibroblasts. The extracts reduced inflammatory cytokines and oxidative stress in the cell model and modestly increased expression of barrier-related genes including filaggrin, loricrin and involucrin [5]. This was an in-vitro experiment with three biological replicates, not a human trial. Its importance is in showing where research is heading: from a single bacterial name to a multi-layered view of metabolites, genes and cell behaviour.
Changing skin, hormones and the microbiome
The relationship between menopause, the gut microbiome and changing skin is an especially interesting frontier. A large 2022 study of 2,300 adults found modest differences between the gut microbiomes of premenopausal and postmenopausal women, including lower estimated potential for a microbial hormone-processing function often called the estrobolome [6]. The study was cross-sectional and did not measure skin outcomes, so it cannot tell us that altering the gut microbiome will change menopausal skin.
Separately, a 2025 study of the facial and forearm microbiomes of 59 younger and older adults found that microbial communities changed with age and differed by body site. Some facial changes were more apparent among female participants, with the authors noting that hormone-related changes in sebum may be one possible influence [7]. These two areas of research are beginning to converge, but the direct menopause-gut-skin pathway has not yet been established in human intervention studies.
Can a probiotic improve the skin?
Possibly in specific circumstances, but the word probiotic is not a complete description of a treatment. Effects are strain-specific and depend on dose, formulation, duration and the condition being studied.
A 12-week randomised, double-blind trial published in 2024 studied a defined oral formulation in people aged 12 to 30 with acne. Among the 74 participants included in the final comparison, 50% of the active group improved on the Acne Global Severity Scale, compared with 29.4% of the placebo group. Improvement on another acne grading measure was 42.5% versus 20.6% [8]. Encouraging as this is, it was one relatively small trial of one specific formulation. It does not mean that any probiotic will improve acne, or that a probiotic should replace established dermatological care.
What can we reasonably take from the research today?
Support the skin barrier directly
A gentle cleansing routine and thoughtfully formulated skincare can support the outer barrier where it is. Topical care and whole-body health are not competing ideas. They act at different parts of the same biological landscape.
Nourish microbial function, not a perfect microbiome
A varied diet that includes fibre-rich plant foods supports microbial fermentation and the production of short-chain fatty acids. Any increase in fibre should be gradual and appropriate for the individual, particularly when digestive symptoms or a diagnosed gastrointestinal condition are present. No single food can guarantee clear or calm skin.
Be cautious with one-size-fits-all supplements
A generic 'gut health' label tells us very little about whether a product matches a person, a condition or the evidence. Probiotics and other microbiome-targeted supplements should be considered by strain, dose, safety and purpose, ideally with qualified guidance when there is an active health condition or concurrent medication.
Do not make the gut responsible for every skin symptom
Acne, eczema, psoriasis, rosacea and persistent irritation are complex conditions with genetic, immune, hormonal, environmental and lifestyle influences. Ongoing or severe symptoms deserve an appropriate medical or dermatological assessment. The gut-skin axis adds another layer of understanding. It does not replace diagnosis.
The Elevanna view
Support the skin directly with thoughtfully formulated skincare while continuing to explore nutrition, microbiomes, hormones, mitochondria and whole-body wellbeing.
Skin is skin, but every person's biology, environment and life stage help shape the conditions in which it functions. At Elevanna, we formulate to support the skin directly while continuing to follow the wider research into microbiomes, nutrition, hormones, mitochondria and whole-body wellbeing.
Evidence-informed care means remaining curious enough to explore emerging science and disciplined enough to say when the evidence is still evolving.
References
-
Trompette A, Pernot J, Perdijk O, et al. Gut-derived short-chain fatty acids modulate skin barrier integrity by promoting keratinocyte metabolism and differentiation. Mucosal Immunol. 2022;15:908-926. View study
-
Blicharz L, Samborowska E, Zagozdzon R, et al. Severity of atopic dermatitis is associated with gut-derived metabolites and leaky gut-related biomarkers. Sci Rep. 2025;15:26146. View study
-
Wang C, Dai S, Zhang S, et al. Gut microbe-derived metabolites drive psoriatic inflammation via modulation of skin Th17 cells. Immunity. 2025;58(9):2241-2255.e7. View study
-
Lian P, Lu R, Gu C, et al. Gut microbiota-induced perturbation in bile acids alter keratinocyte lipid metabolism via FXR-NQO1 signaling in psoriasis. Nat Commun. 2026;17:6590. View study
-
Zhang Y, Zhang Q, Wang M, et al. Multi-omics integration of gut-skin axis in probiotic-treated dermatological conditions. Front Cell Infect Microbiol. 2026;16:1834120. View study
-
Peters BA, Lin J, Qi Q, et al. Menopause is associated with an altered gut microbiome and estrobolome, with implications for adverse cardiometabolic risk in the Hispanic Community Health Study/Study of Latinos. mSystems. 2022;7:e00273-22. View study
-
Swaney MH, et al. Aging-dependent skin microbiome alterations across body sites in a United Kingdom cohort. Front Aging. 2025;6:1644012. View study
-
Eguren C, Navarro-Blasco A, Corral-Forteza M, et al. A randomized clinical trial to evaluate the efficacy of an oral probiotic in acne vulgaris. Acta Derm Venereol. 2024;104:adv33206. View study