Top 25 Functional Medicine Doctors and Leaders to Know

The best functional medicine doctors and leaders are the scientists, practitioners and teachers who built this way of caring for people and carried it to the public, beginning with biochemist Jeffrey Bland, PhD, who founded the Institute for Functional Medicine with Susan Bland in 1991.1 This is my own list of 25 of the most influential people in the field, and I'm number 17 on it, so read it as one practitioner's account of who moved this work forward, with the steps for finding someone near you further down.

What these 25 share is a root-cause way of thinking. A symptom points to a driver somewhere in the body, that driver differs from one person to the next, and with enough patience it can be found and addressed. That's why I believe a root-cause, lifestyle-first approach deserves to be treated as primary care, the first line for the chronic conditions that make up most of modern illness, with conventional medicine as the powerful, essential second line for emergencies, infections and trauma, because what matters is getting the order right. If you're new to the idea, my guide to functional medicine explains what it is and the research behind it, so here I'll stay with the people: what each one did, why it mattered and where you can read their work.

Dr. Josh Axe · Free quiz

Cellular Health Quiz

Loading question one…

Advertisement

Advertisement

Who are the best functional medicine doctors and leaders?

How these leaders built a root-cause approach to health

The best doctors ask why and why and why,2 and functional medicine came together over more than 60 years as each step gave the next person a better way to ask why this particular patient got sick. That question matters for your own body because the same complaint, whether it's fatigue, a rash or a stubborn gut problem, can have one driver in you and a very different one in someone else. One man's medicine is another man's poison, and much of the work on this list is an effort to tell the two apart.

My own lineage runs through several of these names, with Williams for biochemical individuality, Pauling for orthomolecular medicine and vitamin C research, Bland as the field's founder and Hyman for the root-cause framework, and each contributed something specific to how I now practice.

Better physical health in a Cleveland Clinic study of patient results

The most useful test of any idea about the body is what happens to the people who try it. Researchers at Cleveland Clinic, the system that runs the center, looked back through the records of 7,252 adults, 1,595 seen at the Center for Functional Medicine and 5,657 at a family health center, and compared 398 functional medicine patients with 398 closely matched patients from the family health center. At 6 months, the functional medicine patients had gained 1.59 points on a standard patient-reported score of physical health, compared with 0.33 points for the family health center patients, and 30.9% of them had improved by 5 points or more, the change the researchers count as clinically meaningful, compared with 22.1%.7 The authors describe it as the first systematic attempt to collect this kind of patient-reported data on the functional medicine model. By 12 months the gap between the groups was no longer statistically significant, but the functional medicine patients held their gains, and among the 91 matched pairs with scores at both 6 and 12 months, those seen at the center improved significantly more, 2.61 points compared with 0.25.7

The top 25 functional medicine leaders, one by one

These are the 25 as I listed them in my guide to functional medicine, starting with the biochemist who developed the concept.

1. Jeffrey Bland, PhD

Bland is the biochemist who developed the concept of functional medicine, and I name him as its founder. He wanted care to move away from treating the average patient and toward treating the individual one, and in 1991 he and Susan Bland founded the Institute for Functional Medicine to train practitioners to do that. The two of them funded and led the institute through its first decade, and he chaired its board until 2007.1 In 1996 he established the institute's Linus Pauling Award in honor of his mentor, who appears at number 4 below, and several people on this list have received it since. He returned to the board as chairman emeritus in 2013 and still serves in that role,1 and his 2022 paper, "Functional Medicine Past, Present, and Future," is his own short history of the idea.8

2. Mark Hyman, MD

If you've heard the words "functional medicine" on television or on a podcast, there's a good chance Mark Hyman was the one saying them. When Cleveland Clinic opened its Center for Functional Medicine on September 23, 2014, Hyman came in as its director, which gave this approach a home inside one of the best-known hospitals in the country.6 He's a friend of mine and the field's leading public physician voice,9 a sixteen-time New York Times bestselling author whose books include Food Fix and Young Forever, and the host of The Dr. Hyman Show. He remains a practicing family physician who directs his own clinic, and he's a co-founder and the chief medical officer of a lab-testing company.1011

3. Andrew Weil, MD

Weil gave integrative medicine a place in academic training. He founded what's now the Andrew Weil Center for Integrative Medicine at the University of Arizona, where physicians learn to bring natural therapies and conventional care together, and that work makes him the leading academic force on the integrative side of this movement. He remains the center's founder and holds an endowed chair there as a professor of medicine and public health, while Stephen Dahmer, MD, now directs it.12

4. Linus Pauling, PhD

Pauling won the Nobel Prize in Chemistry in 1954 and the Nobel Peace Prize in 1962,13 and he then turned that reputation toward nutrition. In a 1968 paper in Science, he named the idea of orthomolecular medicine, proposing that varying the concentrations of substances normally present in the body might help control mental illness.4 Getting the right molecules to the right levels for the person in front of you runs straight through functional medicine. He died in 1994,14 and his vitamin C research is part of what I draw on in my own work.

5. Roger J. Williams, PhD

Two contributions put Williams on this list. He discovered and isolated pantothenic acid, the nutrient you may know as vitamin B5,315 and in 1956 he published Biochemical Individuality, which argued that people differ enough in their biochemistry to differ in what they need from food. I consider it the foundational text on personalized nutrition. He founded and directed the Clayton Foundation Biochemical Institute at the University of Texas from 1940 to 1963 and was a member of the National Academy of Sciences, and he died on February 20, 1988, at age 94.3

6. Joseph Pizzorno, ND

Natural medicine needed its own schools and standards, and Pizzorno spent his career building them. He co-founded Bastyr University, served as its first president from 1978 to 2000, and led it to become the first accredited college of naturopathic medicine in the United States. With Michael Murray, ND, he co-authored the Textbook of Natural Medicine, now in five editions with more than 100,000 copies in print, which gave naturopathic doctors a scientific reference of their own. He's now Bastyr's chancellor.16

7. Jonathan Wright, MD

Wright founded Tahoma Clinic in 1973 and became an early pioneer of nutritional, bioidentical hormone and preventive medicine. By his own account, he was the first in the United States to prescribe comprehensive hormone replacement using hormones identical to those found naturally in young people, in the early 1980s, and from 1983 he and Alan Gaby, MD, taught physicians how to use nutritional therapy in their practices.17 He officially retired in 2025,17 the year Tahoma Clinic closed.18 He's on this list for the seminars he and Gaby gave to tens of thousands of physicians, and for the hormone work that came out of his clinic.17

8. David S. Jones, MD

Much of what practitioners learn about this field traces to a family physician from Ashland, Oregon. Jones practiced there for 40 years and served as the institute's first president and director of medical education from 2000 to 2013, and he also edited the Textbook of Functional Medicine.1920 His years in family practice shaped the way the institute teaches, which is why its programs cover the relationship between practitioner and patient along with the biochemistry. He received the Linus Pauling Award in 1997, has since retired from clinical practice, and remains president emeritus and vice chair of the institute's board.19

9. Dean Ornish, MD

In a small randomized trial, Ornish showed that an intensive lifestyle program could reduce narrowing of the coronary arteries. In the Lifestyle Heart Trial, 48 people with coronary heart disease were randomly assigned to usual care or to a low-fat vegetarian diet, moderate exercise, stress management, stopping smoking and group support, and 35 of them were followed with angiograms for five years.2122 By then, the average narrowing had shrunk by 3.07 percentage points in the lifestyle group and worsened by 11.77 points in the usual-care group, and the lifestyle group had 25 cardiac events among 28 people compared with 45 among 20.22 The Ornish diet sits at the center of a program that Medicare now covers as intensive cardiac rehabilitation.23

In 2024 his team reported a randomized controlled trial of 51 people with mild cognitive impairment or early dementia due to Alzheimer's disease, in which the lifestyle group did better after 20 weeks than a comparison group waiting to start the program, on three of four cognition and function tests, with the fourth falling just short of statistical significance. He leads the Preventive Medicine Research Institute in Sausalito, California, and holds appointments at the University of California, San Francisco, and the University of California, San Diego.24

10. Sidney MacDonald Baker, MD

Baker's path began with a question he first heard as a student in Kathmandu, where the physician he was apprenticed to would finish with each patient and ask whether they had done everything they could. He trained at Yale, served as a Peace Corps physician in Chad, taught on the Yale medical faculty and later directed the Gesell Institute of Child Development, where his practice widened to children and adults with chronic illness. He came to see symptoms, more than diagnostic labels, as the key to defining what an individual patient needs, an early statement of the biochemical and environmental medicine that functional medicine grew from. His books include Detoxification and Healing.25 The institute gave him its Linus Pauling Award, and he describes himself as one of the founding fathers of functional medicine.26

11. Leo Galland, MD

Galland's great contribution was a way of organizing a patient's story. In a 2006 paper he set out three things to look for, antecedents (the factors that set the stage for an illness), triggers (the things that set it off) and mediators (the things that keep it going), and that language became core vocabulary for functional medicine.5 A board-certified internist with 45 years in practice, he has also studied how intestinal microbes and leaky gut affect health, and the institute gave him its Linus Pauling Award for developing the basic principles of the field. He has written seven books and today serves on a long COVID advisory group.27

12. Terry Wahls, MD

Terry Wahls is a friend of mine who came to food as medicine as a physician and as a patient.28 She was diagnosed with relapsing-remitting multiple sclerosis in 2000, had moved on to secondary progressive disease by 2003, spent four years in a tilt-recline wheelchair, and began the food-based protocol that carries her name in December 2007. By her own account, within a year she could walk through the hospital without a cane and finish an 18-mile bicycle tour.29 She then took it into research. Her WAVES trial randomly assigned 87 people with relapsing-remitting MS to her elimination diet or to the low-saturated-fat Swank diet, with 77 finishing 12 weeks. Fatigue fell on both diets, and at 12 weeks physical quality of life rose 14.5 points on hers and 6.04 points on the Swank diet, a significantly larger gain on hers.30 She's a clinical professor of medicine at the University of Iowa, and her work is one of the clearest examples of food being tested as medicine in autoimmune disease.29

13. David Perlmutter, MD

David Perlmutter, a friend of mine and a board-certified neurologist, took the gut-brain connection and the role of nutrition in brain health to a mass audience, most famously with Grain Brain, a great book that went through a lot of the research on how that connection works,31 and he's now a seven-time New York Times bestselling author. He has received a Linus Pauling Award for his approach to neurological disorders, chairs the Integrative Health Symposium, and serves as an associate professor at the University of Miami Miller School of Medicine.32

14. Patrick Hanaway, MD

Hanaway helped bring this field's training into a major hospital and then helped measure what it did. A board-certified family physician, he became the institute's chief medical education officer and helped develop its 2014 collaboration with Cleveland Clinic, where he served as founding medical director and later as research director.33 He's a co-author of the outcomes study described above.7 In August 2025 he became chief medical officer of a health company, and he continues in clinical practice with his wife, Dr. Lisa Lichtig, in western North Carolina.34

15. Mehmet Oz, MD

A cardiothoracic surgeon by training, Oz exposed millions of people to integrative and preventive health ideas through The Dr. Oz Show. He's now the 17th administrator of the Centers for Medicare & Medicaid Services, confirmed by the Senate in April 2025.3536 I was a regular on his show in 2017.3738

16. Robert Rountree, MD

Rountree has been on the institute's core faculty from the start, teaching nutrition, botanical medicine and complex chronic disease, and in 2015 it gave him its Linus Pauling Award for the years he has spent mentoring and training practitioners, which is how this way of practicing passes from one generation to the next. He has practiced family medicine in Boulder, Colorado, since 1983 and has been medical director of a private practice there since 2002, and he co-wrote Immunotics and contributed to the Textbook of Functional Medicine.39

17. Dr. Josh Axe, DC, DNM, CNS

That's me, and I put myself at number 17 for what DrAxe.com, my books and my show grew into, which is one of the world's largest natural and functional health platforms. Mom's battle with cancer inspired me to begin studying nutrition and functional medicine.40 When I opened my functional medicine clinic in Nashville, Tennessee, I was in my late 20s, and for the first two years I worked 60 to 70 hours a week because I really wanted to help save my town and teach people about natural medicine.41 In 2008 I founded DrAxe.com to carry that same teaching to anyone who wanted it. At its peak my site reached more than 15 million readers a month, and I'm a three-time New York Times bestselling author. Today I co-own The Health Institute, and my clinical work continues through The Longevity Clinic in Franklin, Tennessee. You can read the longer version on my about page.37

18. Izabella Wentz, PharmD

I've respected and admired Izabella Wentz for a long time, and she was one of the first people I saw doing an incredible job getting to the root cause of hypothyroidism, Hashimoto's and autoimmune disease.42 She's a pharmacist who was diagnosed with Hashimoto's thyroiditis in 2009, was surprised at how little anyone could tell her about what lifestyle could do for it, and went looking for answers herself.43 Her books, including Hashimoto's Protocol in 2017, helped carry root-cause care for thyroid problems into the mainstream, and she remains an author and educator. You can hear her in our conversation about thyroid problems and Hashimoto's on my show.

19. Sara Szal Gottfried, MD

Harvard- and MIT-trained, Gottfried helped bring functional hormone care, women's health and precision medicine to a wide readership through four New York Times bestsellers, including The Hormone Cure and The Autoimmune Cure. She now writes as Sara Szal, MD, and she's a clinical assistant professor at Thomas Jefferson University and director of precision medicine and longevity at the Marcus Institute of Integrative Health.4445

20. Chris Kresser, MS, LAc

Kresser's teaching centers on ancestral health, and in 2015 he founded the Kresser Institute, whose training program prepares practitioners to address chronic disease at its source. A New York Times bestselling author, he took that thinking to general readers in The Paleo Cure, and he continues to write, speak and podcast on root-cause care.4647

21. Amy Myers, MD

Myers came to this work through her own struggle with Graves' disease. She founded and ran a functional medicine clinic in Austin, Texas, from 2010 to 2018,48 and her books The Autoimmune Solution and The Thyroid Connection helped popularize functional approaches to autoimmunity, thyroid disease and gut health.49 She continues to write and teach on those subjects, and in 2024 she launched the Take Back Your Health podcast.48

22. Rangan Chatterjee, MBChB

Chatterjee, a general practitioner who qualified from Edinburgh Medical School in 2001 with the British medical degree, the MBChB,50 took lifestyle medicine to British television in 2015 with the BBC One series Doctor in the House, in which he addressed conditions such as type 2 diabetes and anxiety through small daily lifestyle changes. The 4 Pillar Plan and his podcast, Feel Better, Live More, carried those ideas around the world. After 23 years of seeing patients, he stepped away from active clinical practice to teach health care professionals and educate the public, and he's now a visiting professor at Chester Medical School.51

23. Frank Lipman, MD

Early in his career in South Africa, Lipman trusted only what his Western medical training had taught him, and then he saw traditional healers help people he had no way of helping himself. That experience pointed him toward the blend of Western diagnostics and Eastern healing traditions he has practiced for more than four decades, and his books, including The New Rules of Aging Well, helped make root-cause and longevity medicine mainstream. His patient practice is Eleven Eleven Wellness in New York.52

24. Dale Bredesen, MD

Bredesen brought a functional and precision framework to Alzheimer's disease and cognitive decline. A neurologist and the founding president and CEO of the Buck Institute for Research on Aging, he reported on the first 10 patients on his personalized program in 2014, with no comparison group, and nine of the 10 improved on their own report or on testing.53 In a 2022 pilot he co-authored, 25 people with dementia or mild cognitive impairment followed a personalized plan for nine months, also with no comparison group. Their average score on the Montreal Cognitive Assessment, a standard cognitive test, rose from 24.6 to 27.56, 19 of the 25 improved, and the authors called for a larger randomized trial.54 His 2017 bestseller, The End of Alzheimer's, took the program to the public. He's now senior director of precision brain health at Pacific Neuroscience Institute and chief scientific officer of a health company.55

25. Will Cole, IFMCP, DNM, DC

Dr. Will Cole is a close friend of mine,56 so you should know that going in. He was an early virtual practitioner of functional medicine, consulting by webcam with people around the world, and his bestsellers, including Ketotarian and Gut Feelings, have carried this work to a wider audience.57 He and I co-wrote Heal Your Cells and co-founded The Health Institute together.3756 He remains senior clinic director of his own practice and hosts The Art of Being Well podcast.57

How do you find a good functional medicine doctor?

The 25 above built this field, and most of you will want someone closer to home who can see you in person.

I do the same thing myself. I search for a functional medicine doctor in a particular city, and then I'll ask through word of mouth, and that's how you tend to find somebody great.58 The Institute for Functional Medicine also keeps a directory of trained practitioners you can search by location.59

Then look at the person as closely as you look at the credentials. You want somebody with integrity, somebody with values, Judeo-Christian values.60 That might be a functional medicine doctor, an integrative medical doctor or somebody who practices a more ancient form of medicine like Chinese medicine, and if they aren't working through diet, supplementation and lifestyle to do everything they can for your long-term benefit, you don't have the right doctor.60 A good practitioner is licensed, starts with food and lifestyle, and explains why each test is being ordered, because my rule is test, don't guess, and a test is only worth ordering if it will change the plan. The sign I'd watch for most is the cookie-cutter approach, and it happens in my own camp. If every patient on someone's schedule ends up on keto, on carnivore or on the same supplement stack, that practitioner has stopped treating the individual, and you'll do better with someone who builds the plan around your history and your results.

Using this list wisely

This list is a history of the field, and everyone on it earned a place through their influence, which doesn't mean any of these people endorse me, DrAxe.com or any product, or that every therapy each of them has used is right for you. Before you book with anyone, look up their license on your state medical or professional board. And if you have chest pain, trouble breathing, stroke symptoms or any other emergency, go straight to the emergency room, because in that moment conventional medicine is nothing short of miraculous.

The bottom line

Top functional medicine doctors: frequently asked questions

References

1. The Institute for Functional Medicine. Our History.
2. Axe J. She GAVE UP Her Medical License After This... The Dr. Josh Axe Show. 2025.
3. University of Texas at Austin Biochemical Institute. Roger J. Williams: brief biography.
4. Pauling L. Orthomolecular psychiatry. Varying the concentrations of substances normally present in the human body may control mental disease. Science. 1968;160(3825):265-271. PMID:5641253
5. Galland L. Patient-centered care: antecedents, triggers, and mediators. Altern Ther Health Med. 2006;12(4):62-70. PMID:16862744
6. The Institute for Functional Medicine. Cleveland Clinic Opening Center for Functional Medicine. September 15, 2014.
7. Beidelschies M, Alejandro-Rodriguez M, Ji X, Lapin B, Hanaway P, Rothberg MB. Association of the Functional Medicine Model of Care With Patient-Reported Health-Related Quality-of-Life Outcomes. JAMA Netw Open. 2019;2(10):e1914017. PMID:31651966
8. Bland JS. Functional Medicine Past, Present, and Future. Integr Med (Encinitas). 2022;21(2):22-26. PMID:35698609
9. Axe J. 11 Supplements Every 40+ Adult Should Consider. The Dr. Josh Axe Show. 2026.
10. Hyman M. About Dr. Hyman.
11. Function Health. About.
12. University of Arizona Andrew Weil Center for Integrative Medicine. Leadership.
13. The Nobel Prize. Linus Pauling: biographical.
14. Oregon State University Special Collections. The Ava Helen and Linus Pauling Papers.
15. Williams RJ, Lyman CM, Goodyear GH, Truesdail JH, Holaday D. "Pantothenic Acid," A Growth Determinant of Universal Biological Occurrence. J Am Chem Soc. 1933;55:2912-2927. doi:10.1021/ja01334a049
16. Bastyr University. Joseph Pizzorno, ND.
17. Green Medicine Newsletter. About Dr. Wright.
18. Tahoma Clinic. Closure letter, February 10, 2025.
19. The Institute for Functional Medicine. David S. Jones, MD.
20. Jones DS, ed. Textbook of Functional Medicine. Gig Harbor, WA: Institute for Functional Medicine; 2010.
21. Ornish D, Brown SE, Scherwitz LW, et al. Can lifestyle changes reverse coronary heart disease? The Lifestyle Heart Trial. Lancet. 1990;336(8708):129-133. PMID:1973470
22. Ornish D, Scherwitz LW, Billings JH, et al. Intensive lifestyle changes for reversal of coronary heart disease. JAMA. 1998;280(23):2001-2007. Erratum in: JAMA. 1999;281(15):1380. PMID:9863851
23. Lehmann-Haupt R. The Ornish Reversal Program: The First Intensive Cardiac Rehabilitation Program to Be Covered by Medicare. Ornish Living.
24. Ornish D, Madison C, Kivipelto M, et al. Effects of intensive lifestyle changes on the progression of mild cognitive impairment or early dementia due to Alzheimer's disease: a randomized, controlled clinical trial. Alzheimers Res Ther. 2024;16(1):122. PMID:38849944
25. Baker SM. Detoxification and Healing: The Key to Optimal Health. McGraw Hill Professional; 2003. ISBN 9780071812542.
26. Baker SM. Background.
27. Galland L. About Dr. Leo Galland.
28. Axe J. This Is What Happens to Your Body After Antibiotics. The Dr. Josh Axe Show. 2025.
29. Wahls T. About Dr. Terry Wahls.
30. Wahls TL, Titcomb TJ, Bisht B, et al. Impact of the Swank and Wahls elimination dietary interventions on fatigue and quality of life in relapsing-remitting multiple sclerosis: The WAVES randomized parallel-arm clinical trial. Mult Scler J Exp Transl Clin. 2021;7(3):20552173211035399. PMID:34377527
31. Axe J. This Is What Happens to Your Brain When You Heal Your Gut. The Dr. Josh Axe Show. 2025.
32. Perlmutter D. About Dr. Perlmutter.
33. The Institute for Functional Medicine. Patrick J. Hanaway, MD, FMCP-M.
34. Natural Awakenings. Patrick Hanaway on healing the whole person. August 29, 2025.
35. Centers for Medicare & Medicaid Services. Leadership: Administrator Dr. Mehmet Oz.
36. Healthcare Dive. Dr. Mehmet Oz sworn in as CMS administrator. April 2025.
37. DrAxe.com. About Dr. Josh Axe.
38. Axe J. The Medical Freedom War Is Here. Del Bigtree EXPOSES the Pharma Machine. The Dr. Josh Axe Show. 2026.
39. Functional Medicine Coaching Academy. About Robert Rountree, MD.
40. Axe J, Rubin J. The Biblio Diet. Hachette Book Group; 2025. ISBN 9781546008439.
41. Axe J. Why SLEEP is Medicine: My 4 Tips to Improve Energy. The Dr. Josh Axe Show. 2026.
42. Axe J. Thyroid Problems: Everything You Need to Know with Hashimoto's EXPERT Dr. Izabella Wentz. The Dr. Josh Axe Show. 2024.
43. Wentz I. About Dr. Izabella Wentz.
44. Szal S. About Sara Szal MD.
45. Szal S. Books.
46. Kresser C. About Chris, Founder. Kresser Institute.
47. Kresser C. The Paleo Cure. Hachette Book Group; 2014. ISBN 9780316322928.
48. Myers A. About Me.
49. Hachette Book Group. Amy Myers, MD.
50. General Medical Council. The medical register: Rangan Chatterjee, MB ChB 2001, University of Edinburgh.
51. Chatterjee R. About Dr Rangan Chatterjee.
52. Lipman F. Meet the Doctor.
53. Bredesen DE. Reversal of cognitive decline: a novel therapeutic program. Aging (Albany NY). 2014;6(9):707-717. PMID:25324467
54. Toups K, Hathaway A, Gordon D, et al. Precision Medicine Approach to Alzheimer's Disease: Successful Pilot Project. J Alzheimers Dis. 2022;88(4):1411-1421. PMID:35811518
55. Pacific Neuroscience Institute. Dale Bredesen, MD.
56. Axe J. 12 Warning Signs Your Body Is Aging Faster Than It Should. The Dr. Josh Axe Show. 2026.
57. Cole W. About Dr. Will Cole.
58. Axe J. Natural Remedies for Asthma, ADHD, & Aluminum-Free Deodorants: Q&A with Dr. Josh Axe. The Dr. Josh Axe Show. 2024 (at 8:49). YouTube.
59. The Institute for Functional Medicine. Find a Practitioner.
60. Axe J. The Antibiotic Lie and Natural Alternatives. The Dr. Josh Axe Show. 2024 (at 21:01). YouTube.

Dr. Josh Axe, DC, DNM, CNS

Doctor of Natural Medicine · Founder, DrAxe.com

Dr. Axe is a certified doctor of natural medicine, clinical nutritionist, and multiple New York Times bestselling author. He has spent 20+ years in clinical practice helping people heal at the root cause and founded one of the most-visited natural-health platforms in the world.

Read the full bio →

This article is for educational purposes. See our medical disclaimer.