Gut-skin axis

The gut-skin axis (gut-skin axis) is a bidirectional communication system between the gastrointestinal tract, gut microbiota, the immune system, and the skin. Modern dermatology and immunology increasingly indicate that the state of the intestines affects not only metabolism and the body's immunity, but also the condition of the skin, its rate of aging, and the development of many dermatoses. Gut microbiota disturbances can intensify chronic inflammation, oxidative stress, and immune hyperreactivity, which translates into the appearance of problems such as acne, atopic dermatitis, psoriasis, erythema, or excessive skin sensitivity. The gut-skin axis is currently one of the most intensively studied areas of functional medicine, dermatology, and anti-aging cosmetology.

Gut-skin axis – what is it?

The gut-skin axis describes the biological connection between the gut microbiome and the skin through a network of immunological, hormonal, metabolic, and neurological dependencies. Microorganisms inhabiting the gut – bacteria, viruses, fungi, and archaea – participate in the regulation of inflammatory processes, vitamin production, fatty acid metabolism, and the functioning of the intestinal barrier.

A properly functioning microbiota supports:

the balance of the immune system,
the synthesis of short-chain fatty acids (SCFAs),
the integrity of the intestinal barrier,
the control of inflammatory processes,
protection against oxidative stress.

The skin also has its own microbiome, which serves a protective function against pathogens and influences the maintenance of proper pH and the integrity of the hydrolipid barrier. Disruptions in the microbiological balance in the intestines can indirectly affect the skin microbiota and intensify inflammatory reactions.

In recent years, the importance of the gut–brain–skin axis has been increasingly emphasized, indicating that chronic psychological stress can simultaneously disrupt gut function and worsen skin condition. This mechanism explains, among other things, exacerbations of acne, atopy, or psoriasis during periods of increased emotional tension.

Gut-skin axis – how do the intestines communicate with the skin?

Communication between the gut and the skin occurs in multiple ways and involves several key biological mechanisms.

1. Immune system

Approximately 70–80% of the body's immune cells are located within the gut. Gut microflora influences the activity of T lymphocytes, pro-inflammatory cytokines, and immune response mediators. Microbiota disturbances can lead to overactivation of the immune system, which promotes chronic inflammatory skin diseases.

2. Bacterial metabolites

Gut bacteria produce numerous bioactive substances, including:

butyrate,
propionate,
serotonin,
B-group vitamins,
vitamin K.

Short-chain fatty acids exhibit anti-inflammatory effects and support the integrity of both the gut and skin barriers.

3. Neuroendocrine axis

The gut and skin remain under the influence of stress hormones, particularly cortisol. Chronic stress can increase gut barrier permeability (“leaky gut”), leading to the translocation of bacterial endotoxins into the bloodstream and exacerbating skin inflammation.

4. Metabolic processes

The microbiota affects insulin management, lipid metabolism, and androgen activity. For this reason, disturbances of the gut-skin axis are often observed in people with:

hormonal acne,
insulin resistance,
obesity,
polycystic ovary syndrome (PCOS).

Gut-skin axis – dysbiosis and skin problems

Dysbiosis means a disruption of the gut microbiota balance, consisting of a reduction in the number of beneficial bacteria and an excessive proliferation of potentially pathogenic microorganisms. This condition can lead to chronic activation of the immune system and increased permeability of the intestinal barrier.

Studies indicate a link between intestinal dysbiosis and many skin diseases.

Acne vulgaris

In patients with acne, the following are more frequently observed:

decreased microbiota diversity,
chronic inflammation,
increased intestinal permeability,
metabolic and insulin disorders.

A high-sugar and highly processed diet can further exacerbate this process.

Atopic dermatitis (AD)

In children and adults with AD, a reduced amount of protective bacteria is often found, especially Lactobacillus and Bifidobacterium. Dysbiosis can influence immune hyperreactivity and damage to the epidermal barrier.

Psoriasis

In psoriasis, chronic inflammation is observed, associated, among others, with the activation of the gut–skin immune axis. More and more studies indicate a significant role of the microbiome in the activity of the disease.

Rosacea

Patients with rosacea more frequently suffer from gastrointestinal disorders, including:

SIBO (small intestinal bacterial overgrowth),
reflux,
Helicobacter pylori infection.

Treatment of intestinal disorders may lead to a reduction in the severity of skin lesions in some patients.

Gut-skin axis – relationship with inflammation and aging

Chronic low-grade inflammation, referred to as inflammaging, is one of the main mechanisms of body aging. Gut microbiota dysfunction can intensify oxidative processes and the degradation of skin structures.

The most important consequences include:

accelerated collagen degradation,
weakening of the hydrolipid barrier,
increased transepidermal water loss,
greater skin reactivity,
intensification of post-inflammatory hyperpigmentation,
slower tissue regeneration.

Abnormal gut microflora also affects the production of free radicals and protein glycation, which leads to stiffness of collagen fibers and loss of skin firmness.

Increasing importance is also attributed to the impact of the microbiota on:

estrogen metabolism,
ceramide production,
mitochondrial functioning,
fibroblast activity.

From the perspective of aesthetic medicine, the gut-skin axis thus becomes an essential element of anti-aging therapies and the treatment of chronically inflamed and reactive skin.

The gut-skin axis – how to take care of it?

Support for the gut-skin axis requires a comprehensive approach including diet, lifestyle, inflammation reduction, and conscious skin care.

Diet supporting the microbiota

The most significant are:

dietary fiber,
fermented dairy products,
fermented foods,
vegetables and fruits rich in polyphenols,
omega-3 fatty acids,
anti-inflammatory diet.

The following require limitation:

excess sugar,
ultra-processed food,
trans fats,
excessive alcohol consumption.

Probiotics and prebiotics

In specific cases, probiotics containing the following strains may show beneficial effects:

Lactobacillus,
Bifidobacterium,
Saccharomyces boulardii.

The selection of probiotic therapy should take into account the individual clinical problem and the patient's condition.

Stress reduction

Chronic stress significantly disrupts the gut microbiota and the functioning of the skin barrier. The following are of importance:

adequate amount of sleep,
physical activity,
relaxation techniques,
regulation of the circadian rhythm.

Dermatological and cosmetological support

In therapies for chronically inflamed and aging skin, a holistic approach is increasingly used, covering both the restoration of the skin barrier and the reduction of systemic inflammation.

At Ambasada Urody, the following are used, among others:

anti-inflammatory and regenerative therapies,
biostimulating treatments,
procedures supporting the restoration of the hydrolipid barrier,
modern anti-aging therapies,
individually selected skincare programs for reactive and problematic skin.

A comprehensive approach to skin health increasingly considers not only the symptoms visible on the surface of the epidermis but also the state of the gut microbiota, metabolism, and chronic systemic inflammation.