A doctor-led guide

What is functional medicine?

Functional medicine is a patient-centred way of organising a health assessment. It looks at symptoms, medical history, medicines, previous results, lifestyle and personal priorities together. The evidence does not support every test or treatment associated with the label, so each decision still needs a clear clinical reason and appropriate safety checks.

Understand the evidence Explore consultations

Dr Stavroula Nikitopoulou, known as Dr Stavy.

Evidence updated18 August 2026

Plain-English guidePrinciples, evidence and limits

Clinical governanceClinical review pending before production launch

What does functional medicine mean?

Functional medicine is an approach to assessment and care, not a single treatment. It aims to understand how medical history, current illness, medicines, daily life and personal goals interact. A sound approach uses this wider picture without stepping outside evidence-based medicine or delaying conventional investigation.

The label is used in different ways. Some practitioners focus on longer consultations and lifestyle support. Others promote large test panels, restrictive diets or supplements. The name alone does not tell you whether a recommendation is useful, safe or supported by evidence.

In this practice, functional medicine remains part of ordinary medical care. Established diagnoses, prescribed medicines, examination findings and specialist advice are not set aside. The aim is to organise the information more clearly, identify reasonable priorities and make each decision with you.

The principles, and where their limits begin

These ideas can support thoughtful care. They are not proof that every service sold as functional medicine is effective.

See the person, not just one symptom

A full history can reveal patterns, competing priorities and practical barriers. It must still be paired with examination, appropriate investigation and recognised clinical guidance.

Look for contributing factors

Sleep, nutrition, movement, stress, medicines and social circumstances may affect health. Calling something a contributor does not prove that it caused an illness.

Make decisions together

Shared decisions help connect evidence with your goals and preferences. They should include realistic benefits, drawbacks, costs, uncertainty and the option to do nothing for now.

Review the result

A plan should include what will be measured and when it will be reconsidered. If a treatment is ineffective, unsafe or burdensome, it should be changed or stopped.

What happens in a careful assessment?

The process should reduce confusion, not create a bigger list of unconnected findings.

See Dr Stavy's consultation approach

Clarify the main problem
Start with the symptom pattern, what has changed, what has already been investigated and which outcome matters most to you.
Review what is already known
Check diagnoses, medicines, supplements, results, letters and previous treatment before repeating work or adding a new theory.
Identify the next useful question
Decide whether the next step is observation, standard investigation, a targeted test, a treatment review or specialist referral.
Agree how to review the plan
Record what success would look like, what needs monitoring and when to stop, simplify or escalate care.

From our practice

A test should answer a clinical question.

More information is not automatically better information. The next step should be chosen because it has a reasonable chance of improving a decision.

Dr Stavy reviews the history, existing results and current treatment before considering more tests. A test should answer a defined clinical question or have a reasonable chance of changing the next step.

Functional medicine remains integrated with conventional and specialist care, and sometimes the appropriate decision is referral, standard investigation or no additional testing.

Is functional medicine evidence-based?

Some parts can be evidence-based, but the label does not guarantee this. Research on functional medicine as a complete model is limited. Evidence is stronger for some individual elements, such as shared decision-making or specific lifestyle and medical interventions, and weaker or absent for other tests and treatments.

A 2019 retrospective cohort study found a small association between receiving care at a functional medicine centre and better patient-reported physical health at six months. It was not a randomised trial, so it could not establish that the care model caused the difference. The comparison at 12 months was not statistically significant.¹

A 2024 randomised study examined health coaching alongside an elimination diet. Both groups improved, but the primary analysis found no overall difference between coached and self-guided groups. A subgroup result may be useful for future research, but it does not show that the model works for everyone.²

Research on patient-centred care suggests more consistent benefits for satisfaction and self-management than for clinical outcomes.⁴ A recent umbrella review found that shared decision-making tends to have neutral or positive effects and does not usually add cost or consultation time, although results differ by setting.⁵

How to read common claims

Claim or idea	What may be reasonable	What the evidence does not justify
Patient-centred care	More time to understand history, priorities and choices.	Assuming that a longer appointment produces a better health outcome.
Looking for contributors	Considering medical, behavioural and social factors together.	Promising to find one hidden root cause for every condition.
Lifestyle support	Using condition-specific evidence for sleep, nutrition or activity.	Treating lifestyle advice as a substitute for necessary medical care.
Personalised testing	Selecting a validated test that may change a decision.	Ordering broad panels because more data is assumed to be better.
Supplements	Considering a defined indication, dose, duration and interaction check.	Describing products as natural, risk-free or proven to cure disease.

What are the limits and risks?

The main risks are not unique to functional medicine. They arise when uncertain claims, low-value testing, treatment burden or fragmented responsibility replace sound clinical judgement.

A careful approach should

use established diagnoses and guidance where they apply;
explain the quality and limits of evidence;
check medicine and supplement interactions;
define why a test is being considered;
refer or escalate when another service is needed.

Pause if you are offered

a guaranteed root cause, diagnosis or cure;
large test packages without a clinical question;
advice to stop essential treatment without the prescriber;
a long supplement plan without monitoring;
claims that one method works for many unrelated diseases.

A systematic review found wide variation and overuse in diagnostic testing across healthcare. Unnecessary testing can lead to false-positive or incidental findings, further procedures, cost and worry.³ NICE guidance advises discussing benefits, risks, alternatives and the option of no action as part of shared decisions.⁶

How can you judge a provider?

In the UK, the words “functional medicine” do not by themselves tell you a person's regulated profession or scope of practice. Check the underlying qualification, professional register, indemnity, complaints process and who is responsible for follow-up.

Useful questions to ask

What professional register are you on?
What evidence supports this test or treatment?
What might change because of the result?
What are the risks, costs and alternatives?
How will this fit with my GP or specialist care?

A safe answer should include

what is known and what remains uncertain;
the option not to test or treat;
a clear monitoring and stopping plan;
when referral or urgent care is more appropriate;
no promise of a guaranteed outcome.

For the practice’s assessment process and practical details, explore functional medicine consultations with Dr Stavy.

A short history of the term

The Institute for Functional Medicine says it was founded in the United States in 1991. This is useful background on how the field organised itself, but it is not clinical evidence that the model or a particular treatment works.¹⁰

The term has since been used by people from different professional backgrounds and for a wide range of services. That is why the provider's regulated role and the evidence for each recommendation matter more than the label.

Urgent symptoms need urgent care.

Call 999 for a life-threatening emergency, including signs of a heart attack or stroke, severe breathing difficulty, heavy bleeding, a severe allergic reaction, or loss of consciousness. Do not wait for a functional medicine appointment. For urgent help that is not life-threatening, use NHS 111 online or call 111.⁹

Common questions

Short answers to the questions people often ask before deciding whether this approach is right for them.

Functional medicine is a way of organising an assessment around the person's full history, current health, medicines, daily life and priorities. It is not one test or treatment. A responsible clinician still uses established medical guidance, considers other explanations and judges each recommendation by its own evidence, safety and relevance.

Evidence for functional medicine as a complete model remains limited. Some elements, including shared decisions and specific medical or lifestyle interventions, have relevant evidence. Other tests and treatments may not. The useful question is not whether the label is evidence-based, but whether each proposed step is supported, safe and likely to change care.

No. Functional medicine is an approach to organising assessment and care, while conventional medicine is the wider system of diagnosis, treatment, prevention and specialist services. They can overlap. In a doctor-led practice, functional medicine should work alongside prescribed treatment, recognised guidance, standard investigations and referral when these are appropriate.

It should not. A careful assessment starts with history, existing results and current treatment. A new test should answer a defined clinical question or have a reasonable chance of changing the plan. Broad panels can produce unclear or incidental findings, further procedures, cost and worry without improving the decision.

Sometimes assessment identifies an important diagnosis or contributor, but many health problems have several influences and no single hidden cause. “Root cause” should not be a guarantee. A safer approach is to test reasonable explanations, treat what is supported, review the response and keep urgent or specialist possibilities in view.

People from different backgrounds use the term, so check the person's underlying profession and register. A medical doctor should be listed with the General Medical Council. Other regulated professionals have their own registers and scope. Ask who diagnoses, prescribes, monitors treatment, handles results and coordinates with your usual clinical team.

Seek urgent help for severe, sudden or rapidly worsening symptoms. Call 999 for a life-threatening emergency and use NHS 111 for urgent advice when it is not life-threatening. Specialist care may be needed when symptoms, examination findings or results require expertise or treatment beyond the clinician's scope. Functional medicine should not delay either route.

References and guidance

Research records were checked in Consensus. Official guidance is linked directly. Accessed 18 August 2026.

Clinical review: Final review and production sign-off are pending with Dr Stavroula Nikitopoulou.

Beidelschies M, et al. Association of the Functional Medicine Model of Care With Patient-Reported Health-Related Quality-of-Life Outcomes. JAMA Network Open. 2019;2(10):e1914017. Consensus record. doi:10.1001/jamanetworkopen.2019.14017.
D'Adamo CR, et al. Functional medicine health coaching improved elimination diet compliance and patient-reported health outcomes: results from a randomized controlled trial. Medicine. 2024;103:e37148. Consensus record. doi:10.1097/MD.0000000000037148 2024 correction..
Müskens JLJM, et al. Overuse of diagnostic testing in healthcare: a systematic review. BMJ Quality & Safety. 2022;31:54-63. Consensus record. doi:10.1136/bmjqs-2020-012576.
Rathert C, Wyrwich MD, Boren SA. Patient-centered care and outcomes: a systematic review of the literature. Medical Care Research and Review. 2013;70(4):351-379. Consensus record. doi:10.1177/1077558712465774.
Bruch D, et al. The effects of shared decision-making on health outcomes, health care quality, and costs: an umbrella review. Patient Education and Counseling. 2024;121:108408. Consensus record. doi:10.1016/j.pec.2024.108408.
National Institute for Health and Care Excellence. Shared decision making: recommendations. NG197. Published 2021.
General Medical Council. Decision making and consent. Effective November 2020.
Advertising Standards Authority. CAP Code, Section 12: medicines, medical devices, health-related products and beauty products.
NHS. When to call 999.
Institute for Functional Medicine. Our history. Organisational account of the field's development.

Start with the clinical question, not a test package.

If you are considering a doctor-led functional medicine consultation, read how Dr Stavy assesses complex or persistent concerns and decide whether the approach fits what you need.

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