The Silent Tenant: What Mould Is Really Doing to Your Health

March 24, 2026

It’s invisible, it’s sneaky, and it could be the reason you feel like you’re running on empty — every single day.

Let me paint you a picture.

You’re tired — but not the kind of tired that a good sleep fixes. Your head feels foggy. You’re getting random skin flares, maybe a persistent sniffle that never quite turns into a full-blown cold but never fully goes away either.

You’ve been to the GP, your bloods have come back “fine,” and yet… something just isn’t right.

Sound familiar? I hear this story almost every single week in clinic. And one of the first things I start asking about — that most people never think to mention — is their living environment. Specifically, whether there’s any mould in the home.

Mould is one of those health disruptors that flies completely under the radar. It’s not dramatic. It doesn’t announce itself. It just quietly sets up camp in your home and starts interfering with your biochemistry — and most people have absolutely no idea it’s happening.

So today, let’s talk about it — because once you know what to look for, you can do something about it.

What Exactly Is Mould?

Mould is a type of fungus — and before you glaze over at the word “fungus,” stay with me, because this is important.

Unlike bacteria or viruses, mould reproduces by releasing tiny, microscopic spores into the air. These spores are invisible to the naked eye and light enough to float freely. Every time you walk through a room with mould, you’re breathing them in.

Here’s where it gets interesting from a biochemistry perspective. Certain species of mould – particularly Stachybotrys chartarum (commonly known as black mould), Aspergillus, and Cladosporium — produce what are called mycotoxins.

These are naturally occurring toxic compounds that the mould releases as part of its normal metabolic process.

They’re not just mildly irritating — they’re genuinely biologically disruptive, particularly when exposure is prolonged and ongoing.

Mould thrives in moisture, warmth, and poor ventilation. Which, unfortunately, describes a surprising number of spots in the average Australian home.

Where Is It Hiding? (Probably Somewhere You Haven’t Looked)

This is the part I really want you to pay attention to, because mould doesn’t always look like the obvious black spotting on your shower grout.

More often than not, it’s hidden — growing out of sight, quietly colonising spaces you’d never think to check.

Here are the spots I see come up time and again with clients:

Behind bathroom walls and under the floor — especially around baths, showers and toilets. Tiles can look perfect on the surface while the wall cavity behind them is completely saturated with mould.

Inside your air conditioner — the drip tray and internal coils are prime real estate for mould. Every time your aircon kicks on, it can push mould spores directly into the air you’re breathing.
Outdoor sheds and enclosed garages — especially in Queensland’s humid climate. Poor airflow plus heat plus any moisture is a mould paradise.

Under carpet and flooring — particularly in slab-on-ground homes where there’s no subfloor ventilation, or anywhere a slow leak has gone undetected.

Inside walls near plumbing — a slow drip inside a wall cavity can feed mould for years before any damage becomes visible.

Around window frames and sills — particularly in older homes or rooms with condensation buildup during cooler months.

In the ceiling, particularly after any roof leak — even one that seemed minor or was repaired quickly. The moisture can linger long after the leak is fixed.

Inside wardrobes and cupboards that back onto external walls — especially if they’re in a part of the home that doesn’t get much airflow or sunlight

The thing about these hidden spots is that they can be harbouring significant mould growth for months — sometimes years — before anything is obvious.

You might not see it. You might not even smell it. But your body? Your body notices.

What Mould Exposure Does to Your Body

Here’s the bit where I want to be really clear with you. This isn’t about scaremongering.

This is about understanding what’s actually going on biochemically — because when you understand the mechanism, the symptoms start making complete sense.

When you repeatedly inhale mould spores and mycotoxins, a few things happen:

1. Your immune system responds.

It mounts an inflammatory reaction, trying to neutralise what it perceives as a threat.

In the short term, this is actually your immune system doing exactly what it’s meant to do. The problem is chronic, ongoing exposure.

When your immune system is in a constant low-grade state of activation, it starts to affect every system in the body.

2. Mycotoxins can interfere directly with cellular function

Certain mycotoxins have been shown to disrupt mitochondrial energy production — which is your cells’ ability to make energy.

And if your mitochondria aren’t working efficiently, you will be exhausted…… Not tired…… Exhausted.

3. The gut microbiome can be significantly impacted by mycotoxin exposure.

Mould toxins can disrupt the integrity of the gut lining, contributing to what we commonly call increased intestinal permeability (or “leaky gut” in layman’s terms).

When the gut lining is compromised, larger particles can pass into the bloodstream — triggering further immune activation and a cascade of systemic symptoms.

Not everyone reacts to mould in the same way, and this is key.

Genetics play a significant role — particularly variations in genes involved in detoxification, like the HLA-DR gene complex.

Some people can be exposed to significant amounts of mould and feel relatively fine. Others — and these are often the clients who end up sitting across from me feeling completely lost — are genetically predisposed to struggle with mould toxin clearance. Their bodies simply aren’t well-equipped to detoxify and eliminate mycotoxins efficiently.

The Symptom Picture: Does Any of This Sound Like You?

Mould-related illness is often referred to as Chronic Inflammatory Response Syndrome (CIRS) — a systemic, multi-symptom condition that can genuinely mimic a whole host of other diagnoses. Which is part of why it so often gets missed.

The symptoms can span across nearly every body system:

What makes this particularly tricky is that many of these symptoms are vague enough that they get attributed to stress, ageing, being a busy parent, or simply “just how you are.”

And that is exactly what I want to push back on — because these symptoms are your body’s way of telling you something is wrong, and they deserve to be investigated properly.

How Do You Know If Mould Is Your Problem?

Start by asking yourself a few questions:

Do your symptoms feel worse when you’re at home and better when you’re away for a few days?

Have you had any water damage, roof leaks, or flooding — even minor incidents — in the last few years? Think Cyclone Alfred or other floods in the past 5 years.

Does your home feel damp or stuffy in certain areas?

Can you notice a musty smell in any room — even faintly?

Do multiple members of your household have overlapping, unexplained symptoms?

If you answered yes to any of these, it’s absolutely worth exploring further. From a clinical perspective, there are a number of pathways to investigate this properly:

A professional mould inspection of the property — including testing of air quality and surface samples in key areas.

Functional pathology testing — including mycotoxin urine testing, inflammatory markers (TGF-beta1, MMP-9, C4a), and relevant genetic markers.

Visual Contrast Sensitivity screening

A thorough case history with a practitioner who understands mould-related illness — one who will actually ask about your home environment, not just your blood pressure.

What Can You Do Right Now?

If you suspect mould is a factor in your health, here are some proactive steps you can start with today:

Inspect and act on your air conditioner. Have it professionally cleaned and serviced — ideally every 6-12 months. Change or clean filters regularly. This is one of the most impactful things you can do for indoor air quality.

Ventilate properly. Open windows when you cook, shower, and after sleeping. Run exhaust fans in bathrooms and kitchens for at least 10–15 minutes after use. Stale, humid air is mould’s best friend.

Investigate any musty smells seriously. Don’t ignore them or assume it’s just an old house. A musty odour is a biochemical signal — that’s mould releasing microbial volatile organic compounds (mVOCs) into the air.

Support your detoxification pathways. Nutritional support, including glutathione precursors, B vitamins, and specific binders, can assist the body in clearing mycotoxins — but this should be done under the guidance of a practitioner.

Consider a HEPA air purifier in your bedroom. For those sensitive to mould, high-quality air filtration in the space where you spend 7–9 hours every night can make a meaningful difference.

Don’t overlook outdoor areas. If you spend time in your shed, garage, or a poorly ventilated workspace, treat those environments with the same scrutiny as your indoor living spaces.

The Bottom Line

Mould isn’t just a cosmetic issue or a housekeeping problem. For many people, it’s a genuine and significant driver of complex, chronic health challenges — and because it’s invisible, it rarely gets the attention it deserves.

Your home should be your sanctuary — the place where your body gets to rest, recover, and rebuild.

If your environment is silently working against you, the most comprehensive dietary protocol and the best supplement stack in the world will only get you so far.

Health isn’t just about what you eat and how you move. It’s about what you breathe, where you sleep, and what your body is dealing with day in and day out — often without you even realising it.

If any of this has resonated with you, please don’t just file it away as interesting reading. Take it seriously. Start looking. Ask the questions. And if you’d like support working through what might be going on for you specifically, I’d love to help.

Ready to Get to the Bottom of What’s Really Going On?

If you’re experiencing a cluster of the symptoms above and feel like you’re going in circles without answers, a comprehensive naturopathic consultation could be the missing piece. I take the time to look at the full picture — including your environment — not just your pathology results.

Warmly,