📐
See it
Mechanism diagrams built to clinical standard. Not stock art. Not metaphors. The actual biochemical pathway, laid out so you can see what’s happening and why.
📝
Read it
40+ clinical articles across blood chemistry, gut health, hormones, stress, lifestyle, and the TDG methodology. Written in plain language without losing clinical accuracy.
🎯
Apply it
Interactive tools, a clinical pattern finder, and a movement programme. Knowledge that meets you where you are and points toward the next right thing to address.
Free Resources
No email required · No paywall
Visual · Free
Clinical Diagrams
Eight bespoke mechanism diagrams — HPA cascade, gut barrier, oestrogen pathways, insulin resistance, mitochondria & OAT, pregnenolone steal, stress-digestion cascade, and gut-oestrogen cascade. Built to the same clinical standard as the full programme.
8Diagrams
6Body systems
FreeNo signup
Deep-Dive · Free
The HPA Axis — Cortisol, the Awakening Response & Burnout
Cortisol synthesis, the diurnal pattern, the cortisol awakening response, the four stages of HPA burnout, and what the DUTCH measures at each stage. The most complete free resource on adrenal function available.
6Sections
DUTCHConnects to
FreeNo signup
Deep-Dive · Free
The Gut-Brain Axis — Serotonin, Vagus Nerve & Enteric Nervous System
Why 90% of serotonin is produced in the gut, how the vagus nerve carries the gut-brain signal, the neurotransmitters produced in the intestinal wall, and why gut health directly determines mood, cognition, and anxiety.
6Sections
GI-MAPConnects to
FreeNo signup
Deep-Dive · Free
Insulin Resistance — The Decade-Long Process Before Diagnosis
The insulin receptor cascade, GLUT4 transport failure, how resistance develops over years, the intracellular lipid problem, and why fasting glucose is the last marker to change. What to test and when.
6Sections
Blood ChemConnects to
FreeNo signup
Deep-Dive · Free
The Thyroid Conversion Problem — T4, T3, Reverse T3 & Why TSH Alone Fails
Thyroid hormone synthesis, the deiodinase enzymes, why T4 to T3 conversion fails under stress, what disrupts it, and why TSH tells you nothing about peripheral thyroid function. The complete picture.
6Sections
Blood ChemConnects to
FreeNo signup
Read · Free
The Blog
40+ clinical articles across blood chemistry, gut health, hormones, stress, lifestyle, and the TDG story. Each written to explain one thing clearly — not to sell anything.
40+Articles
5Sections
FreeNo signup
Interactive · Free
Health Pattern Finder
40 questions across 7 body systems — HPA axis, gut, hormones, blood sugar, immune, brain, detoxification. Scored clinically to identify your priority patterns and what to address first.
40Questions
7Body systems
2 minNo email
Audio & Book
Listen anywhere · Read in full
Audio · Coming Soon
Test, Don’t Guess — The Audiobook
The Starter Edition — 23,000 words, 20 chapters — narrated in full using a professional voice clone. The complete TDG methodology and clinical philosophy available anywhere you listen. In production now.
20Chapters
23kWords
SoonIn production
Book · £19.99
Test, Don’t Guess — The Book
The complete TDG methodology in print. Blood chemistry, gut testing, hormones, the five integrated tests, and the clinical philosophy behind the approach. Paperback on Amazon or digital Starter Kit with platform access.
290k+Words (full)
£19.99Paperback
AmazonShips worldwide
Movement
Quality before quantity
Movement Programme
Move Well First
Most exercise programmes start with how much. This one starts with how. Five physical attributes. 13 clinical modules. 37 years of coaching intelligence. Built for people whose movement has been compromised by chronic illness, injury, or the long-term effects of poor health — and for those who want to build it right from the start.
13Modules
5Physical attributes
3Tiers
VideosIn production
£497
Self-study · Lifetime access
View programme →
Also available at £1,997 with monthly strategy calls
Deep Dive & Research
Free reference pages · Paid guides from £27
Research · Free
The Evidence Base
The peer-reviewed science behind the Test Don’t Guess approach — functional reference ranges, GI-MAP validation studies, DUTCH hormone research, organic acids clinical data, and the evidence base for functional interpretation over standard population ranges.
View the evidence
Curation · Free
Beyond the Mainstream
Podcasts, books, and apps worth your time — curated from 37 years of clinical practice and continuous learning. The things outside the standard curriculum that have shaped how I think about health, performance, and longevity.
Explore the curation
12 Guides · £37 each
Clinical Guides
Deep dives on specific health areas — gut-brain axis, women’s hormones, men’s health, ADHD, thyroid, cardiac risk, weight loss resistance, autoimmune, stress & HPA, and more. Each one built around what functional testing reveals.
12Guides
£37Each
Interactive Tools · £197
Interactive Clinical Tools
Enter your lab values. Receive personalised interpretation. Blood chemistry, GI-MAP, DUTCH Plus, OAT — each tool built to provide the same level of interpretive depth as a clinical consultation, at your own pace.
5Tools
£197Each
Reading Guides · £27
Reading Guides
Companion guides to the interactive tools — blood chemistry, GI-MAP, DUTCH, OAT, sleep & circadian health. Explanation-first, designed to be read alongside your results or before you’ve had testing.
6+Guides
£27Each
When you’re ready to test
Everything on this page builds toward the same point: understanding what’s actually going on inside your body well enough to know what to test for. When you get there, the TDG programme is where the investigation starts.