About Dr. Diehl

Internal Medicine & Functional Medicine in Frisco, TX

Dr. Diehl

Dina Diehl, DO, is a highly trained and skilled board certified internal medicine and certified functional medicine specialist at Signature Internal Medicine in Frisco, Texas. She has practiced for over 15 years with medical experience at Texas Health, Plano, as a hospitalist and outpatient internist. She has an impressive educational background.

Dr. Diehl completed medical school at Philadelphia College of Osteopathic Medicine in Philadelphia, Pennsylvania. She then attended a residency program at Summa Health System in Akron, Ohio, and also completed some training at the esteemed Cleveland Clinic in Ohio.

Dr. Diehl is only 1 of 1900 providers worldwide that have earned a certification in functional medicine. 

Functional medicine is an individualized patient-centered scientific-based approach that allows patients and the practitioner to work together to address the root cause of disease instead of just treating the symptoms and she uses this approach to promote optimal wellness.  Dr. Diehl combines conventional internal medicine with functional medicine concepts to help her patients achieve their best health.

Dr. Dina Diehl's focus and passion is on health and wellness and is proactive with preventative care. She has experience in treating many chronic conditions such as hypertension, diabetes, hypercholesterolemia, hormone therapy, gut issues and obesity to name a few. She not only treats these conditions but looks to find the root cause of the disease so she can see why her patients are truly unwell. 

In addition to standard lab tests, Dr. Diehl will use advanced testing to look deeper at patients hormone metabolism, gut microbiomes, adrenal gland function, vitamins and genetics when needed.   By using cutting-edge, holistic  testing and technologies Dr. Diehl is able to help patients take control of their health and works closely with her patients during their health care journey . Her caring, friendly demeanor makes them feel comfortable during each visit

Dr. Diehl maintains her medical credentials to stay current with the latest internal and functional medicine advances. She holds medical licenses in Texas, and is a member of the American College of Physicians and Institute for Functional Medicine. 
In her free time, Dr. Diehl loves spending time with her family and friends, traveling, running, golfing, and skiing, as well as watching her children’s sports games and maintaining a healthy lifestyle. 
Dr. Diehl looks forward to caring for her patients using a concierge medicine model, allowing them 24/7 access to providers, same-day appointments, and little to no office wait times. She welcomes them to Signature Internal Medicine and enjoys exceeding their health care expectations.


Dr. Diehl's Memberships and Awards:

  • Certified Functional Medicine Provider (1 of 1900 in the world)
  • Member of  American Medical Association
  • Member of Institute of Functional Medicine
  • Member of Obesity Medicine Association 
  • American College of Physicans 
  • National Committee for Quality Assurance Excellence in Diabetes Care 2017
  • Board member at Texas Health Presbyterian, 2010 
  • Certificate of Recognition for Delivery of Quality Cardiovascular and Stroke Care 2017-2020
  • Top Internist/Top Doctor 2023 
  • America's Most Honored Professionals 2019 - Top 5%
  • America's Most Honored Professionals 2018 - Top 1%
  • America's Most Honored Professionals 2017 - Top 5%
  • Compassionate Doctor 2015
  • Compassionate Doctor 2016
  • On-Time Physician Award - 2016
  • On-Time Physician Award - 2015
  • Patients' Choice 2016
  • Patients' Choice 2018