Organic Acids Test (OAT)
If you’ve ever wished you could just see what your biochemistry was up to, the organic acids test is as close as we currently get without wiring you up to a lab bench.
An organic acids test (often shortened to OAT) looks at tiny compounds your body produces as it breaks down food, makes energy, uses nutrients and deals with microbes. These compounds are filtered by the kidneys and leave the body in urine, which means a simple at‑home urine collection can give a surprisingly wide view of what’s going on under the bonnet. It’s not magic, but it is a helpful way of spotting patterns that don’t show up on standard blood tests.
Different panels vary, but most will include markers related to:
energy production, including how smoothly your mitochondria are running
B‑vitamin status and how efficiently you’re using them
detoxification and antioxidant pathways, including glutathione
byproducts of yeast and certain bacteria in the gut
how you’re handling some amino acids, fats and carbohydrates.
You collect a urine sample at home (usually first thing in the morning), following the lab’s instructions about any foods, supplements or medications that should be paused beforehand. The lab then measures a series of organic acids and compares them with reference ranges; results are interpreted in the context of your symptoms, diet, lifestyle and any other testing you’ve had.
What can an organics acid test show?
This is the bit where expectations need to stay grounded. An OAT does not diagnose medical conditions. It won’t tell you whether you have coeliac disease, PCOS, adrenal fatigue or any of the other labels that float around on social media. What it can do is highlight tendencies: are you burning through certain nutrients more quickly, is there evidence of oxidative stress, do you have markers that make a long‑standing yeast overgrowth picture more plausible, are energy pathways looking supported or a bit sluggish?
In practice, this might look like:
confirming that ongoing fatigue and brain fog sit alongside markers suggesting higher demand for B vitamins, magnesium, or antioxidant support, which then nudges us to prioritise certain foods and, sometimes, targeted supplements rather than guessing.
spotting signs of microbial imbalance that tie in with bloating, sugar cravings or recurrent thrush, which might shift the focus onto gut‑supportive habits, fibre variety and, where appropriate, a structured antimicrobial and rebuild phase.
seeing patterns that help explain why your blood sugar feels wobbly, your energy crashes mid‑afternoon or you struggle with recovery from exercise, and using that to refine your blood sugar balance strategies.
Because the OAT sits firmly in the “functional” camp, you won’t find it in routine NHS practice. GPs are rightly focused on tests that diagnose disease and change treatment quickly; organic acids are more about fine‑tuning nutrition and lifestyle, which doesn’t fit that model. Used well, an OAT can complement GP care by adding nuance to the picture you already have from GP tests and examinations.
Where it becomes unhelpful is when it’s used to sell you a long list of supplements or a very restrictive plan that ignores your relationship with food. Numbers are only useful if they feed back into changes you can realistically maintain: things like building a Mediterranean‑style way of eating, supporting blood sugar steadiness, looking at sleep and stress alongside gut and hormone health, and choosing supplements where they’re genuinely likely to help.
And, as always, no private functional test should delay proper medical assessment. If your symptoms include red flags like weight loss, severe pain, neurological changes, persistent vomiting or signs of infection, your GP and standard investigations come first.
If you’re the kind of person who likes to join the dots – you’ve already worked on foundations and still feel something is missing – an organic acids test can sometimes provide that “oh, that makes sense” moment that helps us prioritise next steps. We can look at it alongside your gut, skin, hormones and energy, rather than in a biochemical silo.
If you’re curious whether an OAT, a comprehensive blood panel, hormone testing or simply going deeper with your current nutrition would be the most useful next step, you’re welcome to book a free introductory call with me.