The Gut–Skin Axis Explained: How Gut Health Impacts Acne

By Lucy Sugars, Nutritional Therapist

If you’ve ever experienced breakouts after antibiotics, bloating with acne flares, or noticed that your skin improves when your digestion does — you’re not imagining it. There’s a powerful connection between your gut health and your skin.

In fact, this link is so important, it’s earned a name in the research world: the gut–skin axis.

As a nutritional therapist, I often tell clients that your skin is a window to your internal health — and one of the key areas we explore is the gut. In this post, I’ll break down how gut imbalances can contribute to acne, and what you can do to support both your digestive and skin health naturally.

What is the Gut–Skin Axis?

The gut–skin axis refers to the two-way communication between your digestive system and your skin, involving:

  • The immune system
  • Hormones
  • The microbiome (gut bacteria)
  • Inflammatory messengers (cytokines)
  • Nutrient absorption

If your gut is inflamed, imbalanced, or sluggish, these issues don’t stay confined to your digestive tract — they often show up in the skin, especially in inflammatory conditions like acne, eczema, rosacea, or psoriasis.

5 Key Ways Gut Health Affects Acne

1. Dysbiosis (Imbalance of Gut Bacteria)
A healthy gut is home to trillions of bacteria that play a role in digestion, immune regulation, and inflammation. When these microbes are out of balance (e.g. after antibiotics, poor diet, or stress), it can result in dysbiosis.

Dysbiosis is associated with:

  • Increased inflammation
  • Impaired detoxification
  • Altered Intestinal Permeability (more on that below)
  • Immune reactivity

These issues create the perfect storm for acne flares, especially if you’re also dealing with hormonal imbalances or a high-sugar diet.

2. Intestinal Permeability (‘Leaky Gut’)
Your gut lining is supposed to act like a sieve — letting nutrients in and keeping larger, inflammatory molecules out. But if the gut lining becomes overly permeable (a condition known as leaky gut), it can allow bacterial toxins (like lipopolysaccharides or LPS) into the bloodstream.

This triggers the immune system and drives systemic inflammation, which may appear on the skin as:

  • Acne
  • Redness or flushing
  • Sensitivity or rashes

Leaky gut is often linked to food sensitivities, chronic stress, excess alcohol, NSAID use, and dysbiosis.

3. Poor Digestion = Poor Nutrient Absorption
Healthy skin depends on nutrients like zinc, vitamin A, omega-3s, iron, and protein. If your gut isn’t functioning well — due to low stomach acid, enzyme insufficiency, or SIBO — you may not be absorbing the very nutrients your skin needs to heal and regenerate.

Signs this could be happening include:

  • Bloating after meals
  • Floating or greasy stools
  • Weak nails or hair loss
  • Fatigue or frequent infections

4. Sluggish Bowel Movements = Hormone Recirculation
One of the ways your body eliminates used hormones (like estrogen and testosterone) is through the bowel. If you’re constipated or not eliminating daily, those hormones can be reabsorbed and recirculated — potentially contributing to hormonal acne, especially on the jawline and chin.

Constipation also reduces the clearance of toxins and inflammatory waste products, which can lead to congestion in the skin.

5. Gut–Brain–Skin Stress Loop
Your gut and brain are constantly talking — and both affect the skin.

Chronic stress disrupts the microbiome, reduces digestive secretions, and increases intestinal permeability. It also triggers cortisol, which raises insulin and worsens oil production.

It’s all connected.

If you’re feeling anxious, not sleeping well, or experiencing stress-related bloating, it’s likely playing a role in your skin health too.

Supporting Gut Health for Clearer Skin

Here’s how I work with clients to support the gut–skin connection:

✅ Prioritise Digestive Function

  • Eat slowly, chew thoroughly
  • Use bitter herbs or lemon water before meals
  • Consider a high-quality digestive enzyme (if appropriate)

✅ Restore the Microbiome

  • Add fermented foods: sauerkraut, kefir, kimchi (or dairy-free alternatives)
  • Include prebiotic fibre: onions, garlic, leeks, oats, flaxseed
  • Reduce sugar and ultra-processed foods that feed the wrong microbes

✅ Repair the Gut Lining

  • Use gut-soothing foods like bone broth, aloe vera, slippery elm, and L-glutamine (under guidance)
  • Avoid your specific food triggers (like FODMAPs, dairy, gluten, or alcohol) if they worsen symptoms
  • Increase colourful vegetables for antioxidants and polyphenols

✅ Support Elimination

  • Aim for at least one well-formed bowel movement daily
  • Stay well hydrated
  • Include chia, flax, and cooked vegetables for fibre

✅ Consider Functional Testing
For persistent or unexplained acne, stool testing (like GI-MAP or GI Effects) can identify:

  • Imbalances in gut flora
  • Yeast overgrowth
  • Digestive insufficiencies
  • Inflammatory markers
  • Potential pathogens

This can help personalise treatment and get to the root of your skin symptoms faster.

The Bottom Line

If you’ve tried every serum, cream, and skincare routine but are still breaking out — it’s time to look below the surface. The gut–skin axis is real, and imbalances in the digestive system can show up as acne, inflammation, and congestion on your skin.

The good news? Your gut is one of the most modifiable systems in your body. With the right support, you can heal from the inside out — and see it reflected in your skin. You can read more about the root cause of acne in my blog post here. 

Interested in exploring your gut health to support clear, glowing skin?
I offer personalised consultations to identify imbalances and create a targeted nutrition and supplement plan to support your skin long-term.

Get in touch if you’d like a deep dive into your gut and skin health, work with me here.