TDG Five-Test Programme Gut Health All Products Resources — Books, Tools & Evidence Health Pattern Finder — Free GI-MAP Guide — £197 DUTCH Hormone Guide — £197 Blood Chemistry Guide — £197 Blog About Book a Call — £145
Clinically-Directed AI · Functional Medicine

Test, Don't Guess.

Your tests came back normal. You don't feel normal. There is a gap between what conventional medicine measures and what optimal health actually looks like. We close that gap.

900+
Biomarkers across 5 tests
200+
Validated clinical patterns
37
Years clinical experience
60+
Clinical education articles
Clinical Focus Areas

The same five tests. Different entry points.

Weight loss resistance and adult neurodivergence are two of the most underserved areas in mainstream medicine — and two of the areas where functional testing reveals the most. The TDG system approaches both through the same rigorous five-test methodology. These pages explain how.

Free Clinical Read
Why Generic Advice Fails — Module 01 of the TDG Clinical Manual
The clinical read that explains why everything you've already tried probably hasn't worked. 35–45 minutes. Free.
Read free →
Five Advanced Tests

Run simultaneously. Read together.

The power is in the cross-referencing. Each test reveals what the others can't — and patterns across all five reveal what none could identify alone.

01
Blood Chemistry
Randox advanced blood panel using functional ranges, not pathological thresholds. Calculated ratios and cross-marker patterns.
150–300 markers
02
GI-MAP Stool Analysis
Complete gut microbiome — pathogen load, dysbiosis patterns, gut immune markers, intestinal permeability, digestive sufficiency.
DNA-based · Quantified
03
DUTCH Plus Hormones
Full diurnal cortisol curve, adrenal reserve, sex hormone production and metabolism, oestrogen detoxification pathways.
Dried urine · Complete picture
04
Organic Acids Test
Mitochondrial function, Krebs cycle efficiency, neurotransmitter production, methylation, B vitamin functional status. Identifies what blood chemistry misses.
Cellular energy · Metabolism
05
Food Sensitivity Panel
IgG4-mediated delayed reactions to 200+ foods — the hidden inflammatory driver that standard allergy tests miss entirely.
200+ foods · Delayed reactions
The Process

Five stages. One clinical investigation.

This is not a consultation followed by a report. It is a structured clinical investigation that reads your biology completely before prescribing anything.

01
Intake — Your Complete Health Story

12 intake assessments covering symptoms, history, lifestyle, biometrics, stress, nutrition, movement, psychosocial health, and gut health. Stephen reads every form personally before your first consultation. Nothing automated.

02
Investigation — Five Tests Simultaneously

Test kits posted directly to you. Blood draw coordinated through your nearest clinic. All five tests run in parallel — results typically returned within 2–3 weeks.

03
Analysis — Pattern Recognition Across Systems

Results run through the TDG Clinical Platform — 30+ specialist analytical tools cross-referencing all five tests against your intake data. The primary driver is identified. The shortest stave is found.

04
Protocol — Your Personalised Programme

A structured, periodised clinical programme built entirely from your data. Nutrition matched to your Metabolic Nature. Evidence-based supplementation at the right doses. Lifestyle sequencing. Nothing generic.

05
Progress — Track, Adjust, Re-Assess

Regular check-ins, protocol refinement as you respond, structured re-assessment. The 120-day red blood cell cycle means meaningful change takes time. We track the right markers at the right intervals.

Why Different

Clinically-directed AI vs generic tools

Every health company now says "AI-powered." The distinction that matters is whether the AI is retrieving information from public data or applying clinical reasoning built from decades of real patient outcomes.

Capability Generic AI / ChatGPT Detective Health Platform
Reference ranges Published population standards Functional practitioner-defined ranges
Cross-test pattern recognition Cannot integrate multiple test types 50+ tools reading all 5 tests simultaneously
Biomarker conflict resolution May give contradictory advice Encoded conflict resolution from 37 years of practice
Clinical context Generic, no patient history integration 12 intake forms read personally before any analysis
Protocol sequencing Not available Periodised, shortest-stave-first sequencing
Watch First

How the TDG approach works

Test, Don't Guess — Stephen Duncan The Five-Test Foundation — Blood, Stool, Hormones, Organic Acids, Food Sensitivity
The Book

Test, Don't Guess

Why your tests are normal and you still feel terrible.

The complete framework behind every clinical investigation I run. How five functional tests — blood chemistry, GI-MAP stool analysis, DUTCH Plus hormones, organic acids, and food sensitivity — map over 900 biomarkers into a single coherent picture that conventional medicine never assembles.

Written by a practitioner with 37 years of clinical experience. Not theory — method. The same approach applied to every client who walks through the door.

Paperback — £19.99 on Amazon Digital Edition — £97

Available worldwide · Amazon paperback · Searchable HTML + PDF digital edition

About Stephen Duncan

37 years of clinical experience. Encoded.

Stephen Duncan is a Functional Diagnostic Nutrition Practitioner (FDN-P) with a BSc Hons in Developmental Biology, an MSc in Coaching Studies & Applied Physiology (Heriot-Watt) (Heriot-Watt University), and 37 years of experience in health and fitness — including competitive boxing, athletics coaching from age 18, and over two decades of functional medicine clinical practice in Edinburgh.

Six years of university study included three years of psychology — a thread that runs directly through how the TDG methodology is applied: every client is read as an individual, every protocol is sequenced to meet the person where they are, and the clinical process is as much about understanding human biology as it is about understanding the human.

The platform was built because nothing like it existed. The clinical pattern recognition, functional reference ranges, and conflict resolution logic were built by Stephen over decades of practice. The AI accelerates interpretation and synthesis. It cannot be replicated by asking ChatGPT the same question.

Stephen co-founded Omnos, an early functional lab data platform, and operates Balanced Fitness in Edinburgh alongside Detective Health clinical practice.

Stephen Duncan
37
Years clinical experience
FDN-P
Functional Diagnostic Nutrition Practitioner
BSc · MSc
Developmental Biology · Applied Sport Science
50+
Clinical analysis tools built
Common Questions

Everything you need to know

What does the TDG programme cost and what's included?
The TDG programme starts at £3,500 and includes all five functional tests, comprehensive analysis using the TDG Clinical Platform, a personalised protocol consultation, and structured follow-up. Complex cases may use the extended 300-marker blood panel at an additional cost. A payment plan is available — ask on the discovery call.
Do I need to come to Edinburgh?
No. Test kits are posted to you directly. For blood chemistry, we coordinate a draw through your nearest clinic — Randox has locations across the UK, and US clients coordinate through Direct Labs. Consultations are via video call. Clients are based across the UK and internationally.
How is this different from seeing a GP or standard private healthcare?
Conventional medicine investigates disease using pathological thresholds — markers are flagged only when significantly abnormal. Functional medicine uses optimal ranges and looks for patterns across multiple systems simultaneously. A ferritin of 22 is "normal" on a standard panel. In functional medicine it can explain fatigue, poor thyroid conversion, and immune dysfunction. The TDG system reads across 900+ biomarkers using functional ranges and cross-test pattern recognition that doesn't exist in conventional healthcare.
How long does the TDG programme take from start to results?
From initial consultation to results consultation is typically 4–6 weeks. Intake forms are completed in the first week, tests are run in parallel, and results are usually returned within 2–3 weeks. The protocol consultation follows within days of receiving all results. Follow-up is at 8–12 week intervals, aligned with the 120-day red blood cell cycle for meaningful re-assessment.
What is the Resilient Gut System and who is it for?
The Resilient Gut System is a 16-week structured coaching programme for people experiencing IBS-type symptoms, stress-driven digestive issues, or unpredictable digestion. It's the right starting point if you want to address the gut-stress connection before committing to the full TDG testing programme — and it serves as a strong foundation for the TDG investigation when the time is right.
Is this programme suitable for people with diagnosed conditions?
Yes, with important caveats. The TDG programme is a functional medicine investigation, not a medical treatment. It works alongside conventional medical care and is not a substitute for it. For clients with serious diagnosed conditions, we work in collaboration with their existing medical team. The discovery call is the right place to discuss your specific situation.
Ready to start?

Stop guessing. Start knowing.

A 30-minute discovery call with Stephen. You explain what's been going on. He explains how the TDG system would approach your specific situation. No obligation — we confirm the fit before anything else.

Understand what your
results are actually saying

New clinical articles by email — fortnightly, no noise. Blood chemistry, gut testing, hormones, detox, and breathwork. The stuff that takes too long to say on Instagram.

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