Functional Medicine in London

Functional medicine in London: testing, not guessing

Functional medicine is the biochemical backbone of integrative care at the London Resilience Clinic. It is a systems-biology approach that looks for the root causes and contributors of illness — not just the label — using advanced testing of blood, urine, stool and saliva to see how your body is actually working. Where standard NHS and specialist tests use a narrow set of markers that often come back “normal”, functional medicine investigates the microbiome, methylation, mitochondrial function, nutrient status, hormones and inflammation, so treatment can target what is really driving your symptoms.

What functional medicine is

Functional medicine is a systems-biology-based approach that focuses on identifying and addressing the root causes and contributors of disease. Each symptom or diagnosis can be the result of more than one cause, and a single cause — such as a chronic inflammatory response — can produce many different diagnoses and symptoms depending on the individual’s biochemistry, environment and vulnerabilities. Only treatments that address the right underlying contributors have lasting benefit beyond suppressing symptoms.

It uses advanced testing of blood, urine, stool and saliva to investigate the drivers of illness that conventional tests from GPs and specialists routinely miss, and detailed genetic, biochemical, biomarker, microbiome and toxin-exposure diagnostics to personalise treatment. It is particularly valuable where a diagnosis is a “final common pathway” — as with depression, chronic fatigue-spectrum illness, fibromyalgia and other poorly understood conditions — and where conventional drug-only approaches have not worked.

Testing, not guessing

The most common experience our patients describe is a stack of “normal” test results alongside symptoms that are anything but normal. Standard laboratory testing uses a narrow range of markers designed to catch overt disease, and it frequently reveals nothing when someone’s biology is subtly but genuinely dysregulated. Functional testing looks instead at how the body is working — the microbiome, methylation pathways, mitochondrial function, nutrient status, immune and inflammatory markers, hormones and circadian rhythm.

Crucially, we test to guide action, not to run tests for their own sake. Every test we order is chosen because the result will change something in the plan — a specific nutraceutical, a dietary adjustment, a targeted gut protocol. This removes the guesswork of what will work best for a specific person, targets treatment to the real underlying contributors, and — because it lets us prepare the ground and personalise doses — tends to mean faster, cleaner results with fewer side effects, which matters greatly for the sensitive patients we so often see.

What we test for

Tests are chosen for the individual case, but our toolkit commonly includes:

• Comprehensive stool analysis — the microbiome, dysbiosis, fungal and mould-illness markers, digestion and absorption, and gut inflammation
• Organic acids testing (OAT) — a urine window into brain chemistry, mitochondrial function, yeast overgrowth, neurotransmitter metabolism and detoxification
• Methylation and folate-cycle genetics (such as MTHFR), often via cheek swab, alongside functional methylation markers
• Mitochondrial and micronutrient assessment — cellular energy, and levels of magnesium, zinc, B vitamins, vitamin D, omega-3s and more
• Inflammatory and oxidative-stress biomarkers, and stress-hormone (HPA-axis) and circadian-rhythm testing
• Hormone and thyroid panels, and, where indicated, mycotoxin, latent-infection or IgG food-sensitivity panels
• In certain cases, additional tests may be used, such as mycotoxin panels.

Testing is optional and always proportionate — in children we use non-invasive methods such as cheek swabs and urine wherever possible.

What we do with the results

Functional testing only matters if it leads to action. Results are interpreted alongside your full clinical picture, history and symptom map, and then translated into a personalised plan — a specific therapeutic diet, targeted clinical-grade nutraceuticals, a “remove, repair, restore” gut protocol, mitochondrial or methylation support, or a folinic acid trial where indicated. In some cases, functional biomarkers can also be used to track treatment progress over time alongside clinical measures, so both you and your medical team can see what is working.

Because integrative medicine is still medicine, functional testing sits within a complete medical plan. The point is never testing for its own sake — it’s precise, data-led treatment integrated into your overall medical care plan.

The conditions functional medicine helps

Functional medicine is most powerful in complex, multi-system and drug-resistant conditions, and it underpins our treatment of:

• Chronic fatigue and ME/CFS, long covid and post-viral illness
• Fibromyalgia and chronic pain
• MCAS, EDS and hypermobility, and mould illness
• Depression, anxiety and OCD
• Neurodivergence — ADHD, autism and AuDHD (see our neurodivergence hub)

In neurodivergent people in particular, functional testing frequently uncovers the gut, methylation and mitochondrial roadblocks that standard care never looks for.

Functional medicine as part of an integrative plan

Functional medicine is one of the core methods within integrative medicine — the umbrella under which we work — rather than a standalone service. Testing identifies the drivers; the wider plan then treats them. In practice it is stacked with the clinic’s other pillars for a synergistic effect: microbiome medicine and therapeutic diets to repair the gut, targeted nutraceuticals, nervous system regulation, personalised medication and, where appropriate, cannabinoid medicine.

This is what allows us to move beyond disease management toward genuinely improving energy, mood, resilience and quality of life. Food and supplements alone are rarely enough in complex chronic illness, but without addressing the underlying biology that functional testing reveals, longer-lasting change is hard to achieve.

Frequently asked questions

Functional medicine is a systems-biology approach that looks for the root causes and contributors of illness rather than just treating the label, using advanced testing of blood, urine, stool and saliva to see how your body is actually working — and then treating what it finds with personalised diet, nutraceuticals, gut work, nervous system regulation and, where needed, medication.

No — testing is optional and always proportionate. We recommend it where the result will change your plan, and we choose the least invasive tests possible, particularly for children. Much can be achieved clinically without testing, but where used, it lets us target treatment precisely and personalise doses for sensitive patients.

Standard tests use a narrow range of markers designed to catch overt disease and often come back “normal” even when your biology is genuinely dysregulated. Functional testing looks at how the body is working — the microbiome, methylation, mitochondria, nutrients, hormones and inflammation — the drivers standard panels miss.

Yes — the London Resilience Clinic offers North-American-style functional and integrative medicine, led by Dr Dani Gordon, with particular expertise in complex, multi-system and drug-resistant conditions and in neurodivergent patients.

Functional medicine, delivered by specialist doctors

• Testing that leads to treatment. Every test is chosen because the result will change your plan — never testing for its own sake.
• Specialist medical doctors only. Functional findings are interpreted and acted on by integrative medical doctors who can prescribe and investigate.
• One integrated plan. Functional medicine stacked with microbiome work, nutrition, nervous system regulation, medication and cannabinoid medicine for a synergistic effect.
• Built for complex, sensitive patients. Precise, personalised, and paced for people who react to everything.