Functional medicine is a complementary assessment approach that treats a complaint not as the problem of a single organ but as the result of the relationship between the digestive, immune, hormonal and nervous systems. Instead of attaching a disease label, it asks “which process is producing this symptom?” I trained in functional medicine on top of my specialty in anaesthesiology; I run the assessment alongside your existing treatment, not instead of it.
This page explains the approach and how the consultation proceeds. The interventional and complementary methods I use for pain are on the pain treatment page.
What functional medicine is — and is not
Medical training teaches you to diagnose a symptom and treat the diagnosis; that is correct and necessary. Functional medicine does not replace it; it widens the picture around the diagnosis. Two people with the same diagnosis differ in sleep, nutrition, gut health, stress response and deficiencies; the functional assessment measures those differences and builds them into the plan.
What it is not: it is not alternative medicine, it does not take you off your medication, and it does not take over the follow-up of a diagnosed condition from the relevant specialty. I do not stop the medication you are taking; the assessment comes alongside your existing treatment, not in place of it.
What do people come with?
The following are conditions I assess; this is not a “list of conditions treated”.
- People whose tests are “normal” yet who do not feel well: chronic fatigue, waking unrefreshed, energy dips through the day
- Recurrent digestive complaints: bloating, irregular bowel habit, suspected food sensitivity
- Disturbed sleep, feeling constantly on alert, complaints related to the stress response and cortisol rhythm — what is commonly called “burnout”
- People with a diagnosed thyroid or autoimmune condition, for the regulation of nutrition, sleep and deficiencies alongside their existing treatment
- Assessment of triggers in chronic and widespread pain, fibromyalgia and recurrent headache — the framework of methods is on the pain treatment page
- Non-dietary factors in weight management: sleep, stress response, insulin resistance; together with dietitian follow-up and, where needed, acupuncture as support
Increased intestinal permeability, commonly known as “leaky gut”, is a concept still under research; I treat it as one marker in the assessment, not as a diagnosis on its own.
How does the consultation proceed?
- First consultation — 60–90 minutes. The history of the complaint from its onset to today, sleep, nutrition, digestion, stress, past infections and medication use are discussed in detail. Existing test results and reports are read together.
- Test plan. The symptom decides the test list; I do not order the same panel for everyone. The classes I order when needed: an extended thyroid panel, vitamin and mineral levels, inflammation markers, indicators of insulin resistance and, where relevant, a breath test for gut bacterial balance. I do not name laboratories or brands; whichever test is needed, that one.
- Plan. Results are interpreted together at the second consultation and the plan is given in writing.
- Follow-up. Whether the plan is working is assessed at a follow-up consultation; the timing depends on the complaint, and I do not make promises by the calendar.
What does the plan include?
The core of the plan is dietary adjustment, sleep hygiene, recommendations to regulate the stress response, movement and, when needed, oral supplementation. I plan ozone and IV therapies as supportive measures when needed; the core plan is oral supplementation and lifestyle adjustment. I explain these on the ozone therapy and IV therapy pages.
Fewer procedures, more conversation. I do not order a test I do not consider necessary, and I do not recommend a supplement I do not consider necessary.
Limits
Functional medicine is complementary; it is not the place for emergencies or acute conditions. Follow-up of a diagnosed condition continues with the relevant specialty; I work alongside that follow-up. I do not make promises such as “permanent recovery” or “eliminating the root cause”; the goal is to measure the processes producing the symptom and correct those that can be corrected. I do not publish a general figure for how long results take; that depends on the complaint and the person.
Who is not suitable
- People seeking to stop their current medication — I do not plan consultations for that purpose
- New, severe symptoms requiring urgent assessment — the relevant specialty first
- Undiagnosed symptoms that may be serious — diagnosis first, functional assessment second
- In pregnancy, diagnosed chronic disease and ongoing medication, the test and supplement plan is made together with the treating physician
Suitability is always determined at consultation.
Pricing
Under the applicable regulations, price information cannot be published on our website. The cost of a treatment depends on the product used, the technique chosen and the extent of the treatment. You can call the clinic for detailed information.
Frequently asked questions
Will I have to stop my medication for functional medicine?
No. I do not stop the medication you are taking; the functional assessment comes alongside your existing treatment, not in place of it. If a change in medication is needed, it is decided together with the prescribing physician.
Is functional medicine just a diet?
Nutrition is an important part of the plan but not the whole of it. Sleep, the stress response, digestion, deficiencies and movement are addressed together; oral supplementation is added when needed.
Which tests are ordered in functional medicine?
The symptom decides the test list; the same panel is not ordered for everyone. When needed: an extended thyroid panel, vitamin and mineral levels, inflammation markers, indicators of insulin resistance and a breath test for gut bacterial balance.
My tests came back normal. Can I still have a functional medicine assessment?
Yes; this is a common reason for coming. The “normal” range may not be the best value for you; the functional assessment reads results together with the symptom and completes any missing tests.
Where do IV and ozone fit into functional medicine?
As support, when needed. The core plan is nutrition, sleep, the stress response and oral supplementation; IV or ozone does not replace that plan and is added alongside it if required.
Planning your visit
My clinic is in Nişantaşı, Şişli, on the European side of Istanbul, approximately 45 minutes from Istanbul Airport.
The first functional medicine consultation can be arranged in person in Istanbul or remotely. If tests are needed, results are reviewed together at a second consultation and the plan is given in writing; follow-up is arranged remotely.
Consultations are conducted in English. Follow-up after you return home is arranged remotely, and I remain reachable for any questions during the period in which the result develops.
Dr. Ömer Fatih Şahin — Specialist in Anaesthesiology and Reanimation Diploma Registration No: 113606
Published: 22 February 2026 · Last updated: 2026-09-21 This content has been medically reviewed by Dr. Ömer Fatih Şahin.