Mould is a common problem in UK homes and workplaces, particularly in older or poorly ventilated buildings, and anywhere damp or condensation has taken hold. For some people, ongoing exposure is linked to a real, if easily overlooked, pattern of symptoms.
What does mould exposure look like?
Symptoms linked to mould exposure vary between people and can include fatigue, brain fog, respiratory irritation, sinus congestion, headaches and skin irritation. None of these are unique to mould exposure on their own, which is part of why it's so often overlooked or misattributed to something else.
Is "mould illness" medically accepted?
The allergic and respiratory effects of indoor fungi are well established and not in dispute. The broader idea of chronic "mould illness," sometimes called CIRS (Chronic Inflammatory Response Syndrome), as a defined, standalone medical diagnosis is a different matter, and it remains debated within mainstream medicine.
The American College of Medical Toxicology has stated that while allergic effects of fungi are documented, the role of inhaled mycotoxins in causing toxic health effects in indoor residential environments remains doubtful, citing limitations in the underlying studies. Exposure modelling research indicates that the maximum inhaled dose of mycotoxins likely to occur in a mouldy environment is well below the levels known to cause harm. "Sick building syndrome" is recognised in the medical literature as a pattern, but it doesn't have a diagnostic test attached to it. Diagnosis rests on symptom history, documented environmental exposure and ruling out other causes, not a single marker. Some research has reported structural brain differences in people with CIRS-type presentations following exposure to water-damaged buildings, but this research hasn't been validated to the standard mainstream medicine requires. None of this means mould exposure isn't real or isn't worth investigating. It means testing gives you a marker of exposure, not a diagnosis, and it works best alongside a practitioner who can weigh it against your symptoms and history.
What does a mycotoxin test actually measure?
A mycotoxin test measures mycotoxin metabolites in urine, using validated LC-MS/MS (liquid chromatography-tandem mass spectrometry) methods. This is an important detail to understand before you test: mycotoxins detected in urine primarily reflect dietary exposure, from foods like grains, nuts and coffee, rather than inhalation from indoor mould. Commonly measured urinary mycotoxins, including aflatoxin M1, ochratoxin A, deoxynivalenol, zearalenone metabolites and fumonisin B1, are predominantly dietary in origin. Because most mycotoxins clear the body relatively quickly, a urine test isn't a reliable way to confirm remote or ongoing inhalation exposure from a water-damaged building. As the American College of Medical Toxicology puts it, it's inappropriate to attribute mycotoxins found in urine to a suspected past inhalation exposure. Testing is most useful where there's a known exposure history alongside otherwise unexplained symptoms, as one data point to bring to that conversation rather than confirmation on its own.
What happens during testing?
Testing is done from home with no GP referral required. You order online, collect a urine sample using the kit provided, and view your results in your dashboard once processed. From there, we'd recommend booking time with a practitioner experienced in environmental or integrative medicine to interpret the result properly in the context of your history and symptoms.
Does a clear result rule out mould as a factor?
Not necessarily. A single mycotoxin test is a snapshot, and results can be affected by timing, hydration and individual metabolism. Because urine mycotoxin levels primarily reflect recent dietary exposure rather than inhalation from indoor mould, a positive result doesn't necessarily confirm building-related exposure either, and interpretation needs to weigh up all possible exposure sources. If you have a strong exposure history and ongoing symptoms despite a clear result, that's a conversation for your practitioner rather than something the test alone can settle.
What if I've already been diagnosed or suspect exposure?
If you're past the "is this mould?" stage and focused on recovery, our guide on mould toxicity and nutritional support covers how diet and lifestyle can support your body's detox pathways during recovery.
Next steps
If your symptoms and exposure history line up, testing can be a useful starting point. View the full range of mould and environmental toxin tests, including the Mycotoxin Mould Exposure Test, heavy metal testing, and hair mineral analysis.
The information in this article is for educational purposes only and is not a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of your physician or another qualified healthcare provider with any questions about a medical condition. If you suspect mould exposure or are experiencing related symptoms, consult a healthcare professional for personalised guidance.
