The Gut-Skin Axis: How Microbes Influence Your Skin From Within

5 Jun

As a naturopath, I’m often asked about the connection between gut health and the skin — and the science behind it is becoming increasingly clear. The gut-skin axis describes a fascinating two-way communication system between the gut microbiota and the skin, mediated by microbial metabolites, immune signaling, and even hormones.

Let’s take a look at how metabolites and neurotransmitters produced by our gut bacteria can influence systemic inflammation, barrier function, and ultimately skin health.

Microbial Metabolites: Messengers from the Microbiota

Our gut is home to trillions of microbes that ferment dietary fibres into short-chain fatty acids (SCFAs) like butyrate, acetate, and propionate. These metabolites don’t just benefit our digestive system — they also have:

✿ Anti-inflammatory effects, reducing systemic inflammation that can trigger acne, eczema, and psoriasis.

✿ Skin barrier support, by enhancing tight junctions and improving skin hydration.

✿ Immune modulation, which is crucial for preventing autoimmune-related skin conditions.

📖 One study showed that individuals with acne often have reduced microbial diversity and lower SCFA production, suggesting an impaired gut barrier and heightened systemic inflammation (Ding et al., 2020).

Neurotransmitters: Microbial Influence on Mood and Skin

Gut bacteria like Lactobacillus and Bifidobacterium species can produce neurotransmitters such as serotonin, GABA, and dopamine — many of which interact with the gut-brain-skin axis.

Stress is a known aggravator of skin conditions, and these microbiota-derived neurotransmitters help:

✿ Regulate mood and stress resilience

✿ Influence the hypothalamic-pituitary-adrenal (HPA) axis, reducing cortisol spikes that damage skin integrity

✿ Improve sleep, which is vital for skin repair

Fun fact: over 90% of the body’s serotonin is produced in the gut!

Hormonal Interactions: The Endocrine Link

Microbial enzymes can impact oestrogen metabolism, thyroid conversion, and even androgen activity — all of which play roles in skin conditions like:

✿ Hormonal acne (linked to excess androgens)

✿ Melasma and hyperpigmentation (affected by oestrogen)

✿ Dry or thinning skin (linked to low thyroid function)

The microbiome plays a role through the estrobolome — a collection of bacteria that metabolise oestrogens. Dysbiosis here can lead to oestrogen excess or deficiency, influencing sebum production, pigmentation, and collagen synthesis.

Practical Support for the Gut-Skin Axis

Support your microbiome for glowing skin by focusing on:

✿ A high-fibre, plant-rich diet (to fuel beneficial bacteria)

✿ Fermented foods (such as sauerkraut, miso, and kefir)

✿ Stress reduction (consider vagus nerve support, meditation, or adaptogens)

✿ Targeted probiotics: Certain strains (like L. rhamnosus GG and B. longum) have been shown to improve skin clarity and reduce inflammation.

Understanding the gut-skin axis changes how we approach skin conditions in naturopathic practice. By supporting gut microbial health, we can reduce inflammation, modulate hormones, and create conditions for the skin to thrive from the inside out.

This growing field is a reminder that beautiful skin truly begins within.