About Us

Advanced Functional Medicine's mission is to utilize the latest scientific research to diagnose and formulate a customized treatment plan for each individual patient to help reverse chronic disease, eliminating the need for dangerous or unnecessary drug or surgical interventions. We have created a practice that we believe in and choose for our own family members.

What Is Advanced Functional Medicine?

Based on cutting-edge science, functional medicine offers a whole new way to understand and look at chronic illnesses from diabetes to heart disease; autoimmune disease to fibromyalgia; thyroid to anxiety, and more. The core concept is that chronic illness is an outcome of imbalances in the key underlying physiological systems in your body. When inflammation, blood sugar imbalances, insulin resistance, oxidative stress, hormonal problems, and systemic upsets occur, the body spirals out of balance.

At Our Clinic Health Is Being Restored:

  • Blood sugar, triglycerides and cholesterol levels are normalizing.
  • Hormonal imbalances are corrected.
  • Stubborn weight is coming off.
  • Energy levels are being dramatically improved.
  • Pain and aches are reduced and resolved.
  • Brain fog is lifted.
  • Mental clarity returns.
  • Sleep difficulties are improved.

Meet The Doctors


Dr. Matthew Willis, DC, DABCI

Dr. Matthew Willis, DC, DABCI

Dr. Willis has completed over 4 years of post-doctorate education in functional medicine, diagnosis & internal disorders, and is a board certified diplomate internist (DABCI). Dr. Willis believes that we all deserve a life of great health—and that we can create it for ourselves. That’s why he is dedicated to treating the root causes of chronic disease by using the dynamic model of Functional Medicine, which has been transforming the way healthcare is practiced. He is a practicing doctor, a recognized leader, speaker, educator, and advocate in his field. He is also the founder and director of Advanced Functional Medicine of San Diego and Advanced Functional Medicine of Los Angeles, a speaker for the nonprofit group Doctors for Health and Wellness, and has been a regular medical contributor on many functional medicine and integrative health websites around the country. He is a member of the nationally recognized Institute for Functional Medicine, the Council on Diagnosis of Internal Disorders, and an active member of the American Diabetes Association.


Dr. Sonia Mohan, MD

Dr. Sonia Mohan, MD

Dr. Sonia Mohan has years of research experience in pathology at the renowned Cedars Sinai Medical Institute in Los Angeles, CA. This was followed by post-graduate residency training in the field of Pathology and Laboratory medicine at Loma Linda University Medical Center. Most recently, seeking a transition from the confines of traditional medicine and learning about the many advantages of a whole-body approach, Dr. Mohan has now dedicated her career to healing, using the latest research in functional medicine. It is Dr. Mohan’s full intention to target the root causes of illness and embrace the patient’s true path to a long-term well being. Serving as owner and medical director of Advanced Functional Medicine has enabled Dr. Mohan to fulfill her patient’s needs in a more comprehensive and fulfilling manner than typical conventional medicine allows.

San Diego

Los Angeles

Office Hours


Saturday by Appointment Only

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