Functional medicine occupies a polarised space. Its advocates call it the future of healthcare. Its critics call it pseudoscience. The truth — as with most things in medicine — is more nuanced.
What functional medicine gets right
Root cause thinking. Conventional medicine excels at acute treatment but often manages chronic conditions symptomatically. Functional medicine's emphasis on understanding why a condition has developed — not just treating what has developed — addresses a genuine gap.
Time with patients. Functional medicine consultations typically run 60–90 minutes. This allows for the detailed history-taking and pattern recognition that 10-minute GP appointments simply can't accommodate.
Lifestyle as medicine. The evidence for nutrition, exercise, sleep, and stress management as foundational health interventions is robust. Functional medicine practices that emphasise these are on solid ground.
Where functional medicine goes wrong
Unvalidated testing. IgG food intolerance panels, comprehensive stool analyses with unproven markers, salivary cortisol patterns interpreted beyond their evidence base, heavy metal provocation testing — these are commonly ordered in functional medicine and have limited or no validated clinical utility.
Supplement stacking. The £200-per-month supplement regimen that many functional medicine practitioners recommend is rarely supported by evidence for the individual patient. Some supplements have good evidence in specific contexts. Wholesale supplementation based on speculative mechanisms does not.
Lack of regulation. Anyone can call themselves a functional medicine practitioner. There's no protected title, no standardised training, and enormous variation in quality. A functional medicine doctor (MBBS-qualified) operates very differently from a functional medicine "health coach" with an online certification.
How to evaluate a practitioner
Check their medical qualifications. Ask what evidence base supports the tests they're ordering. Ask whether the supplements they recommend have RCT evidence for your specific condition. If the answer to any of these is vague, be cautious.