Save with a Bundle
Curated combinations at a reduced price — for when you know you need more than one.
The Five-Test Interpretation Bundle
All five PDF reading guides covering every test in the TDG programme — GI-MAP, DUTCH Plus, Blood Chemistry, OAT, and Food Sensitivity. Everything you need to understand your results across all five tests.
- GI-MAP Interpretation Guide
- DUTCH Plus Hormone Guide
- Blood Chemistry Interpretation Guide
- OAT Interpretation Guide
- Food Sensitivity Framework
The Interactive Tools Bundle
All four interactive interpretation tools in one bundle — enter your results and receive personalised clinical interpretation across blood chemistry, hormones, gut, and organic acids.
- Blood Chemistry Interpretation Tool
- DUTCH Plus Hormone Guide Tool
- GI-MAP Stool Analysis Tool
- OAT Interpretation Tool
The Metabolic Health Bundle
The three guides that address the metabolic picture together — weight loss resistance, blood sugar and insulin, and the supplement framework that supports both. The complete metabolic investigation starting point.
- Weight Loss Resistance — Clinical Investigation
- Blood Sugar & Metabolic Health
- Before You Buy Another Supplement
The Brain & Nervous System Bundle
The three guides covering the neurological and stress picture — ADHD and neurotransmitter balance, the gut-brain axis, and the HPA axis. The upstream drivers of focus, mood, and cognitive function.
- ADHD & Brain Health
- The Gut-Brain Axis
- Stress & the HPA Axis
Bundle links active once Gumroad listings are created — see individual products below while bundles are being set up
The Resilient Gut System™
A 16-week structured gut health coaching programme. Three tiers — The Map, The Investigation, The Case — from self-directed study to full clinical investigation with GI-MAP testing and practitioner oversight.
The Map
The complete 16-week programme — all 8 modules, five phases, video lessons, and protocols. Self-paced via Practice Better. Lifetime access.
- 8 guided modules — all five phases
- Practice Better portal access
- Metabolic Nature nutrition module
- Lifetime access
The Investigation
Everything in The Map plus GI-MAP stool analysis, full written interpretation, and one 60-minute strategy consultation.
- GI-MAP included
- 1 strategy consultation (60 min)
- Test-guided protocol
- Written results summary
The Case
GI-MAP, three strategy consultations, full practitioner oversight at every phase transition, and direct messaging throughout.
- GI-MAP + 3 strategy consultations
- Full clinical oversight
- Direct messaging throughout
- OAT upgrade option (+£895)
Full programme details and GI-MAP order form → rgs-programme
Your GI-MAP stool test, ordered and interpreted by me in full. Quantitative PCR analysis of bacteria, parasites, fungi, inflammatory markers, and gut barrier integrity. Full written report, priority action plan, and a 45-minute results call. The fastest way into the TDG clinical framework without committing to the full five-test programme.
Interactive Clinical Tools
Enter your values. Receive personalised interpretation. Browser-based — not PDFs.
GI-MAP Stool Analysis Guide
Enter your GI-MAP values. Personalised interpretation of every marker — pathogen load, microbiome, digestive function, permeability, and severity-routed clinical next steps.
- All GI-MAP sections personalised
- Catches pathogens standard culture misses
- Severity-routed clinical next steps
- Single HTML file — works in any browser
Blood Chemistry Interpretation Guide
Enter your results. Functional interpretation — pattern recognition, cross-marker relationships, and clinical significance at a level standard lab reports never reach.
- Functional vs standard reference ranges
- Personalised pattern recognition
- RDW, HbA1c, fasting insulin in depth
- Single HTML file — works in any browser
OAT Interpretation Guide — Interactive Tool
Enter your OAT values across six sections. Personalised interpretation, five clinical patterns detected, priority action plan. Includes Quick Reference Guide PDF companion.
- All six OAT sections personalised
- Five cross-section pattern detectors
- Priority action plan from your results
- Includes Quick Reference Guide PDF
Blood Chemistry Health Audit
Comprehensive functional interpretation of your blood values — functional ranges, cross-marker patterns, and clinical significance beyond what standard lab reports provide.
- Functional vs standard reference ranges
- Full pattern recognition engine
- Cross-marker clinical relationships
- Single HTML file — works in any browser
Clinical Programme
Complete structured protocol — three phases, three intensity levels, week by week.
8-Week Detoxification Programme — Complete Clinical Protocol
The real biochemistry of detoxification — Phase I and Phase II liver enzyme pathways, binders, sauna, and the food matrix. Not a juice cleanse. Week-by-week supplement tables at three intensity levels, troubleshooting for detox reactions, pre-protocol readiness checklist, pre/post testing markers, and a full maintenance calendar covering daily through annual practices.
Clinical Guides — £37
Deep dives from the Test, Don't Guess framework — the science, the testing, and the targeted protocol.
Blood Sugar & Metabolic Health
The insulin resistance epidemic begins a decade before fasting glucose rises. The five-stage metabolic timeline, how the natural GLP-1 system works, why HbA1c is a lagging indicator, and what the five-test investigation reveals that standard testing misses entirely.
- Five-stage insulin resistance timeline
- Why fasting insulin beats HbA1c for early detection
- The natural GLP-1 system explained
- What testing reveals before diagnosis
Men's Health: A Functional Approach
Most men with low testosterone don't need TRT — they need to know why it's low. Eight suppression drivers, the LH diagnostic key, the three-phase optimisation protocol, hair loss beyond finasteride, prostate, male fertility, and the fertility caveat that must precede any TRT conversation.
- LH — the marker that changes everything
- Three-phase natural optimisation protocol
- The fertility caveat before any TRT prescription
- Two detailed clinical case studies
Immunity, Inflammation & Detoxification: The Clinical Trinity
Recognition, response, resolution — one continuous process in three phases. Interrupt any phase and you convert an acute appropriate response into a chronic problem. Covers omega-3 and the resolution mechanism, Phase I/II liver biochemistry, autoimmunity, and why sIgA is the most important marker practitioners never measure.
- Why suppressing inflammation often perpetuates it
- Omega-3 and the resolution mechanism
- Phase I/II liver detox biochemistry
- The functional approach to autoimmunity
Stress & the HPA Axis: A Deep Dive
The master regulator that conventional medicine almost never investigates. Why high and low cortisol patterns need different emphasis. The cascade through thyroid, sex hormones, blood sugar, gut, and immunity. Includes the practitioner's personal account of new parenthood, sleep deprivation, and hormonal breakdown.
- Three HPA stages with stage-specific protocols
- Cortisol's cascade through six body systems
- Vagal tone — trainable, not fixed
- The personal clinical account
The Gut-Brain Axis
Your gut has 500 million neurons. The vagus nerve is 80% gut-to-brain. How Clostridia blocks the dopamine-norepinephrine pathway. How the tryptophan steal explains treatment-resistant depression. The OAT marker that identifies it. The five-priority intervention sequence.
- Clostridia blocking the dopamine-norepinephrine pathway
- Quinolinic acid — the treatment-resistant depression marker
- The oestrobolome and hormone-gut-brain link
- Five-priority intervention sequence
Women's Health & Hormones
PCOS is a metabolic condition — the pill doesn't treat it. Oestrogen dominance is frequently a gut problem. Perimenopause is years of unpredictable fluctuation. Four PCOS phenotypes, the 2-OH/4-OH oestrogen pathways, the oestrobolome, MTHFR and oestrogen methylation, and two detailed clinical cases.
- Four PCOS phenotypes with distinct protocols
- Beta-glucuronidase — the gut driver of oestrogen dominance
- The 2-OH/4-OH/16-OH metabolite ratios that matter
- Catherine's perimenopausal transformation
Food Sensitivity Results: A Clinical Framework
How to act on your results without creating nutritional gaps — integrated with GI-MAP, OAT, DUTCH, and blood chemistry. The 4-day rotation protocol, conflict resolution when tests disagree, and the full reintroduction sequence.
- Four-test integration framework
- 4-day rotation protocol
- Conflict resolution when tests disagree
- Reintroduction sequence and timing
ADHD & Neurodivergence: The Biochemical Investigation
Most adults with ADHD have been offered medication without anyone investigating the underlying biochemistry. Four biochemical clusters — dopamine-norepinephrine, gut-brain axis, methylation, and blood glucose instability — each measurable, each addressable.
- Four biochemical clusters with protocols
- The dopamine-norepinephrine pathway in detail
- Gut-brain axis and neurotransmitter production
- Why stimulant medication is not always enough
Autoimmune: Root Cause Investigation
Autoimmunity is not random. Molecular mimicry, intestinal permeability, and the environmental trigger triad — infection, gut, and toxin load — are identifiable and addressable. Why immunosuppression alone is insufficient.
- Molecular mimicry and trigger identification
- Intestinal permeability as the gateway
- Environmental trigger triad
- Five-test investigation for autoimmune drivers
Cardiac Risk: Beyond Cholesterol
Total cholesterol is a poor predictor of cardiovascular events. ApoB, Lp(a), HOMA-IR, hsCRP, and the triglyceride:HDL ratio tell a fundamentally different story. The metabolic drivers standard lipid panels miss.
- Why total cholesterol is a poor predictor
- ApoB, Lp(a) and particle-level risk
- Insulin resistance as the primary driver
- The functional cardiac risk assessment
Muscle, Recovery & Performance
Performance isn't built in the gym — it's built in recovery. Iron status, thyroid conversion, cortisol rhythm, testosterone, and mitochondrial efficiency all determine whether training produces adaptation or breakdown.
- Iron, ferritin, and oxygen-carrying capacity
- Cortisol rhythm and overtraining markers
- Testosterone and recovery capacity
- Mitochondrial efficiency on OAT
Weight Loss Resistance
Five biological patterns that block fat loss regardless of caloric intake. The investigation standard medicine never runs — and the intervention sequence that determines whether anything else works.
- Five clinical patterns with full protocols
- Why the same diet fails different people
- Six-level intervention hierarchy
- Three clinical case studies
The Complete Gut Restoration Protocol
The 12-week gut restoration sequence used in the TDG clinical programme. Four phases — remove, replace, reinoculate, repair — with specific supplement stacks, dietary modifications, and testing checkpoints at each stage. Covers SIBO, leaky gut, dysbiosis, and post-antibiotic restoration.
- Four-phase 12-week protocol in full
- Phase-specific supplement stacks and dosing
- Dietary modifications by phase
- GI-MAP and OAT testing checkpoints
Common Conditions Quick Reference
19 conditions. The conventional approach, what functional testing reveals that standard medicine misses, and the priority investigation sequence — for each one. From chronic fatigue and thyroid dysfunction to autoimmune conditions, weight loss resistance, anxiety, and skin conditions.
- 19 conditions mapped across 6 categories
- Conventional vs functional approach for each
- Priority test sequence per condition
- The investigation that changes outcomes
The Caffeine Protocol
Caffeine doesn't give you energy — it blocks the signal that tells you you're tired. The adenosine mechanism, HPA axis interaction, CYP1A2 metaboliser types, the 90-minute rule, and what your DUTCH results may be revealing about your caffeine pattern.
- The adenosine mechanism explained
- Fast vs slow metaboliser — and why it matters
- Cortisol pattern-specific guidance
- Four-week intelligent reset protocol
The Placebo & Nocebo Effect
The placebo effect is not imagination — it is measurable neurobiology. And the nocebo effect is equally real, equally measurable, and far more consequential in clinical practice than most practitioners acknowledge. Why expectation directly affects biological outcomes.
- The neurobiological mechanism in full
- Three nocebo patterns in functional medicine
- Clinical communication framework
- Self-compassion and health outcomes — the research
Client Transformations
Eight real cases from nearly forty years of working with people. The presenting picture, what testing revealed, what changed, and the clinical lesson that generalises. The same symptoms in different people almost never have the same cause — these cases show why.
- Eight detailed clinical cases
- Full investigation and protocol for each
- The transferable clinical lesson per case
- Covers fatigue, hormones, gut, autoimmune, cardiac risk and more
Reading Guides — £27
Companion reading guides to the interactive tools and the broader framework.
OAT Interpretation Guide
Six sections, 40+ markers, five clinical patterns. Microbial, energy, neurotransmitter, detoxification, and amino acid markers — with cross-test integration.
Blood Chemistry Interpretation Guide
Functional ranges, cross-marker patterns, and clinical significance beyond standard lab reports. The companion reading guide to the interactive tool.
Clean Skin — The Toxic Load Investigation
The average woman applies over 160 chemicals to her skin before leaving the house. This guide maps the enzyme competition mechanism, the oestrogen disruption pathway, the biomonitoring data, and the practical framework for reducing toxic load — without replacing your entire bathroom cabinet at once.
Before You Buy Another Supplement
What actually works, what to test first, when to take it. 14 core supplements reviewed — timing, interactions, quality markers, and test-first protocols.
Move Well First — Quick Reference
All 13 Move Well First modules distilled to one non-negotiable each — with clinical notes connecting each to your functional test results.
Audiobooks — Clinical Education You Can Listen To
Narrated by Stephen Duncan MSc FDN-P in his own voice. Clinical depth — accessible anywhere.
Test, Don't Guess — Starter Edition
The flagship audiobook. Why your tests came back normal and you still feel terrible — and what functional testing reveals that standard investigation doesn't. Twenty chapters covering blood chemistry, gut health, hormones, organic acids, and the lifestyle foundations every protocol depends on. Narrated by the author.
- 20 chapters · approximately 3 hours
- The five-test approach explained in full
- Seven body systems — what disrupts each and what testing reveals
- Protocol sequencing — how to build a plan that holds
Test, Don't Guess — Gut Health
Why your gut won't settle — and what testing actually reveals. SIBO, leaky gut, the migrating motor complex, what the GI-MAP shows, what the OAT adds, and how to build a gut protocol that holds. Ten focused chapters.
- 10 chapters · approximately 30 minutes
- SIBO, SIFO, leaky gut — mechanisms explained
- GI-MAP and OAT cross-reading
- Protocol sequence — why order matters
Test, Don't Guess — Hormones
Why your hormones are out of balance — and what testing actually reveals. The HPA axis as master regulator, cortisol pattern reading, the thyroid conversion problem, oestrogen metabolites, progesterone, testosterone, and the perimenopause years. Ten focused chapters.
- 10 chapters · approximately 40 minutes
- DUTCH Plus explained — what standard testing misses
- Oestrogen metabolite pathways in plain language
- The upstream approach to hormonal balance
Test, Don't Guess — Detoxification
The five detoxification systems — liver and bile, fatty liver and insulin, kidneys and mineral regulation, lymphatic drainage, and the gut's SCFA ecology. Each system explained in clinical depth, with what testing reveals and what to do about it.
- Five focused chapters — the detox series
- Liver Phase I and II, bile, beta-glucuronidase
- Kidneys, lymphatic drainage, butyrate
- Available shortly — join the email list to be notified
The Detective Health Audiobook Library
All four audiobooks in one bundle. Approximately 4.5 hours of clinical education narrated by the author — covering the complete TDG approach to testing, gut health, hormones, and detoxification. Save over £12 versus buying individually.
- Test, Don't Guess — Starter Edition (~3 hrs)
- Test, Don't Guess — Gut Health (~30 mins)
- Test, Don't Guess — Hormones (~40 mins)
- Test, Don't Guess — Detoxification (~30 mins)
Books & Full Programmes
The complete clinical education — from the full book to the clinical manual and movement science.
The Metabolic Natures Programme
For “every diet works for someone else”. A starting reading on two axes from a questionnaire, a food guide, menu plan and recipes for your plate, and a follow-up where the plan is checked against how you actually cook and eat. A starting point, not a test result.
Test, Don't Guess — Digital Edition
The full book. Volumes 1 and 2. From body systems and the five-test programme through metabolic typing, intervention protocols, and clinical conditions. Written before I reworked metabolic typing into Metabolic Natures: read that part as a starting point, not a tested rule.
- 37 chapters across two volumes
- Metabolic typing questionnaire (the older version of the Metabolic Natures starting reading)
- Full clinical appendices A–Y
- Includes the practitioner's story
The TDG Clinical Manual
A complete functional medicine education across 13 modules — from why generic advice fails through the five-test programme, metabolic typing (now reworked as Metabolic Natures: a starting point, not a tested rule), hormonal balance, and building your personalised protocol.
- 13 modules, 8+ hours of clinical reading
- Nutrition, stress, gut, hormones, metabolism
- Metabolic typing questionnaire (the older version of the Metabolic Natures starting reading)
- Protocol-building framework
The Science of Movement as Medicine
Why how you move matters more than how much you move. VILPA, Zone 2, power training for longevity, and five clinical training templates matched to your functional test results.
- 12 chapters of movement science
- DUTCH, OAT & GI-MAP integration
- Five clinical training templates
- The motor learning neuroscience
TDG Starter Kit
The complete introduction to the Test, Don't Guess approach — what the five tests reveal, what drives the most common patterns, and how to decide whether the full programme is right for you.
- Full TDG methodology overview
- The five-test programme explained
- Common clinical pattern frameworks
- Decision guide for next steps
45 minutes. You complete your Case File first and I prepare your Health Status Report from it, so we start with your picture. Clear direction, a specific testing pathway, and an honest conversation about which programme, if any, is the right fit. The £145 is credited against a programme if you go ahead within 60 days, not against single tests. Not sure yet? The free 20-minute call comes first.
A written answer to one question, within 3 working days. Fill in a short form, attach anything useful (wearable screenshots, old results, what you take now), and I reply with what I think is going on, one or two things to try, whether a test would answer it, and anything that means your GP instead. One follow-up question within 14 days is included, and the £45 comes off a check-in, consultation, test or programme booked within 60 days. Prefer to talk? A 30-minute check-in, £75. Everything for existing clients is on one page.
Individual specialist tests and paired investigations that answer specific clinical questions — available separately from the TDG five-test programme.