Medical Advisory Board

Dr. David K. Hill

Founding Executive

Throughout the world it is difficult to find an active doTERRA Wellness Advocate who doesn’t know and admire Dr. Hill. His rare combination of natural abilities to listen, love, and teach is well enriched with his vast understanding and knowledge of pure essential oils and how they collectively and independently offer solutions for health and wellness. As a founding executive, Dr. Hill has mentored thousands of Wellness Advocates throughout the history of doTERRA, which has helped cultivate the unique culture found within the organization. As the leading expert in essential oils at doTERRA, he challenges his team to find only the highest quality botanicals and ingredients and provide superior safety standards. He shares his knowledge openly in order to empower everyone to use these gifts of the earth and continues to find new and exciting products for the market.

Dr. Hill encourages the medical community to look at supplementary options when healing the whole person and encouraging wellness. He looks forward to a future where the essential oil community and modern medicine can co-exist in a doctor’s office so that people will have more options and control of their healthcare. Until this day arrives, he will continue to collaborate with the medical community through studies, trials and capable physicians.

Dr. Russell Osguthorpe, MD

CMO, Chief Medical Officer

Dr. Russell Osguthorpe currently serves as the chief medical officer of doTERRA. He’s establishing a network of primary care clinics focused on wellness and prevention through integrative, evidence-based medical practices. His work at doTERRA also revolves around directing research on the use of essential oils in healthcare settings. Dr. Osguthorpe received his medical degree from the McGill University School of Medicine, completed his residency at the Children’s Hospital in Denver, Colorado, and Pediatric Infectious Diseases Fellowship at Washington University School of Medicine.

Dr. Brannick Riggs, MD

VP of Clinical Initiatives; Chairman, Medical Advisory Board

Dr. Brannick Riggs was born in Lafayette, Indiana, but was raised in various parts of the world. He is a board certified Family Practitioner. In 2001, he graduated from the University of Arizona College of Medicine in Tucson while receiving some of his training in complementary and alternative medicine. After graduation, he was privileged to attend the McKay-Dee Family Practice Residency Program, which brought him and his family to Ogden, Utah. He enjoys treating the full spectrum of family medicine and is a member of the American Academy of Family Physicians. Dr. Riggs served as Medical Director of his busy five provider practice as well as for a nursing home and two hospice groups. He has also served as the Northern Utah Medical Director for Revere Health from 2014–2017. 

Dr. Riggs has a strong interest in value-based healthcare and is passionate about changing the profession that he loves for the betterment of patients and physicians. He was honored to have received the Patients’ Choice Award for seven consecutive years. He is now Chairman of the Medical Advisory Board and Vice President of Clinical Initiatives for doTERRA. He enjoys using the oils in his home and integrating them into his medical practice to bless the lives of patients. When not working, Dr. Riggs and his wife, Juli, enjoy spending time with their five children in the outdoors of the Wasatch Front. They garden, tend to their small farm, and love to travel the world together.

Dr. Katherine Igah-Phillips, MD, MHA

Dr. Katherine Igah-Phillips—affectionately known as Dr. K—is an award-winning international speaker and holistic humanitarian. She focuses on the power behind mental, physical, emotional and spiritual wellness. Dr. K uses her private integrative medicine practice to give her community access to a space for holistic, natural, and authentic medicine, delivered by a team of like-minded healers. She also offers a virtual mentorship program, where she creates and holds the space for personal development and elevation of consciousness. Dr. K maximizes her life purpose by providing the tools and coaching necessary for people to access genuine healing, holistic elevation, and a fulfilling reality that they love.

Dr. Paul Winterton, MD

Paul W. Winterton is a Board Certified Orthopedic Surgeon. He earned his medical degree from Harvard Medical School in 1993 and completed his Orthopedic Surgical Residency at the Mayo Clinic in 1998. Following residency, he completed two fellowships at The Institute For Bone and Joint Disorders in shoulder and knee reconstructive surgery/sports medicine, as well as foot and ankle reconstruction in Phoenix, Arizona.

Currently, Dr. Winterton serves on the Board of Councilors for The American Academy of Orthopedic Surgeons. For a number of years he has advocated the integration and practical use of essential oils in his practice. As a member of the Scientific Advisory Board for doTERRA, he is currently researching the basic science, cell biology, and clinical application of essential oils. He is a strong proponent of the practical use of essential oils and dietary supplements in the home, as well as in the traditional western medical clinical setting, particularly with regard to bone and joint well-being.

Dr. James Geiger, MD

Dr. Geiger has been an anesthesiologist since 1986. He graduated from the University of San Francisco and worked in a San Francisco hospital doing cardiac anesthesia for his father who is a retired cardiothoracic surgeon.

Dr. Geiger has also been an aromatherapist since 2004 and it was in the hospital’s recovery rooms where he first noticed nurses using essential oils and aromatherapy to prevent and treat post-operative nausea. The diligent doctor was intrigued and began studying the scientific literature on the subject. He soon recognised that sciences, such as anatomy, physiology and the chemistry applications of aromatherapy, were similar to anesthesia. He was determined to figure out how to integrate aromatherapy safely into his life and the lives of others, including his operating room patients.

Much of Dr. Geiger’s time is spent doing anesthesia, serving on committees and giving lectures and webinars on the safe use of essential oils in hospitals and surgical centers to improve patient care. Currently, he is on staff at several medical centers, orthopedic hospitals and surgical centers, where he has introduced therapy with essential oils into the operating and recovery rooms.

Dr. Joshua Yorgason, MD

Dr. Yorgason, a native of Salt Lake City, Utah, is an ear, nose and throat surgeon. He obtained his medical degree at Columbia University in New York, and did his residency at the University of Utah. He has been involved in research of drug toxicity and hearing restoration in Los Angeles at the prestigious House Ear Institute, and at the University of Utah. He obtained further fellowship training in ear surgery at the University of Minnesota, and now works in Bismarck, North Dakota for Sanford Health as a cochlear implant surgeon and hearing and balance specialist. He is a clinical faculty for the University of North Dakota.

While in practice for the past five years, he has been supportive of alternative medicine, and has used essential oils in his practice. He is a clinical faculty for the University of North Dakota.

Dr. Jessica L.M. Herzog, MD, FAAP, ABHIM

Dr. Herzog is a board certified Holistic Integrative Medicine physician and pediatrician who is devoted to true wellness. She currently practices in York, PA and lives with her husband and three children in Baltimore County, Maryland. She completed her undergraduate degree, medical doctorate, and pediatric residency at the University of Maryland. During her studies, she was involved in research at the NIH and the University of Maryland, and although she loved the basic science, she found her true calling at the bedside of sick newborns and children. She has worked as a pediatric hospitalist in Maryland, Utah, and Pennsylvania. Wellness is a lifestyle that she demonstrates and teaches to her family, friends, patients and their families, medical students, residents, and colleagues. She is a daily user of doTERRA essential oils. She believes that essential oils are a modern miracle of medicine that will continue to shape healthcare worldwide.

Dr. Gregory L. Woodfill, D.O.

Dr. Gregory L. Woodfill is a board certified Obstetrician and Gynecologist. He completed his medical training at Michigan State University College of Osteopathic Medicine in 1997 and completed his residency in Obstetrics and Gynecology there in 2001. Dr. Woodfill was elected chief resident from 2000–2001 and educated medical students as clinical faculty at Michigan State University College of Osteopathic Medicine 1998-2002. Upon completion of residency, he developed the women’s health program at the Virginia College of Osteopathic Medicine and served as Department Chairman of Obstetrics and Gynecology from 2001–2008. He has previously served as Department Chairman of Obstetrics and Gynecology at Wythe County Community Hospital and as Division Chief of Obstetrics and Gynecology at Wilmington Health Associates. He currently lives in Wilmington, NC, where he performs a full scope of practice with emphasis in minimally invasive office procedures, advanced laparoscopy and urogynecology. He also provides clinical education to the residents at SEAHEC where he was honored to be elected Professor of the Year in Obstetrics and Gynecology 2014-2015.
Dr. Woodfill and his wife, Ashley, co-founded East Coast Oils (ECO), where they study the safe and effective use of essential oils and direct research for the advancement of essential oils in professional health-care settings and home use. He provides education for many health-care providers and Wellness Advocates across the US.

Dr. Amy Wolthoff, MD

Dr. Amy Wolthoff grew up in Grapevine, Texas (a suburb of Dallas). In 2009, she received her Doctor of Medicine from the University of Texas Health Science Center in San Antonio, Texas. Dr. Wolthoff completed her internship year of Internal Medicine at Texas Health Resources Presbyterian Hospital, Dallas, Texas. She then joined the Department of Dermatology at the Texas Tech Health Science Center in Lubbock, Texas, where she received the Resident Leadership Award for recognition in superior leadership qualities, professionalism, teamwork and dedication to the residency program. She completed her Dermatology Board Exam and became Board Certified in Dermatology July 2013.

Since starting in private practice in Dallas, Texas Dr. Wolthoff has been blessed with many awards from both her patients and peers including “Three Best Rated Dermatologist in Dallas 2016”, “Texas Super Doctors Texas Rising Star” from 2014-2017, “Top 10 Doctor 2015”, “Most Compassionate Doctor” from 2013-2017, and “Patient’s Choice Award” from 2013-2017.

Dr. Andrew Gough, DO

Dr. Andrew Gough was born and raised in England to parents who both practiced medicine and believed in the effectiveness of alternative medicine. He completed a Sports Science degree from Chelmsford College before moving to the States where he graduated with honors from BYU-Idaho where he studied Psychology and Chemistry. Dr Gough graduated from the founding school of Osteopathic Medicine, Andrew Taylor Still University and completed his Residency in Emergency Medicine in the St. Joseph Hospital System in Detroit, Michigan.

Dr. Gough is currently practicing Emergency Medicine at Sanford Hospital in Aberdeen, South Dakota. He is passionate about learning, studying, and educating people about the many health benefits of dōTERRA essential oils and natural products and is dedicated to sharing how essential oils have blessed his family and continue to bring hope and healing to so many people worldwide.


Dr. Christopher M. Spelman, DDS

Dr. Chris Spelman is a general dentist in private practice in New Jersey. He graduated with honors from the University of Maryland in 2001. Dr. Spelman is a Member of the Academy of General Dentistry and offers a full scope of dental services in his practice. He studies essential oils extensively and uses them regularly in his dental practice. He has a passion for educating both his patients and colleagues about the importance of living a wellness-based lifestyle.

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