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You’ve had standard blood tests. You’ve been told everything is fine. You don’t feel fine. This is the most common presentation we see — and the gap between “within reference range” and “functioning optimally” is exactly what functional testing closes. The TDG five-test programme is designed for this.

Gut health is the most common single-system starting point. If gut symptoms are your primary concern and you want to begin there before committing to the full five-test programme, the GI-MAP Entry Programme gives you a complete picture of your gut ecology, barrier integrity, and digestive function — with full interpretation and a results call.

Hormonal disruption is almost always multi-system — thyroid conversion, adrenal activation, oestrogen metabolism, and gut health all interact. The DUTCH Plus hormone panel, read alongside blood chemistry, gives you the complete picture. Start with the discovery call to establish which tests are most relevant to your specific hormonal pattern.

Start with the clinical education — 60+ articles, six clinical diagrams, and the TDG Starter Edition (available as a book, digital edition, or audiobook). The Learn page is the best entry point. Read the case studies to see what functional testing actually finds. When you’re ready, the discovery call takes 20 minutes.

Low fat, low carb, paleo, keto, plant-based — each has people it transformed and people it made worse, and the difference is not willpower. Metabolic Natures is a structured way of working out which balance of food suits you: two physiological axes, read together, with the strength of each shown rather than hidden. It is a starting point rather than a test result, and the page states plainly what the evidence for it is and is not.

The Detective Health clinical suite includes interpretation guides for all five functional tests, a practitioner workflow, and the TDG clinical manual. The FDN-P certification is the training foundation the entire TDG approach is built on. The For Practitioners page covers everything.