We solve and prevent health problems using functional medicine, advanced testing and nutrition.

At root,

We’re dedicated to helping you address the root causes of your symptoms in order to restore wellness and prevent disease.


Functional Medicine

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We're a team of Institute of Functional Medicine trained MDs and Functional Dietitian Nutritionists. True Functional Medicine is what we do.

root offers

a therapeutic partnership whether you haven’t found answers for the way you’ve been feeling, or you simply want access to the most advanced care and prevention.

We consider your unique genetic and biochemical make-up, microbiome, environment, lifestyle, and nutrition.

We empower you with the right information for a healthy lifestyle and support you on your journey to heal from the inside out.

As Seen In

patient testimonials

Working with Dr. Marzena Slater and Amy Masterson has been the most rewarding health experience. First, they want to hear your story, not just a list of your symptoms. You are working with health professionals who listen and validate your concerns! I've struggled with getting traditional doctors to believe that I had issues when their tests weren't registering it. After confirming a diagnosis of Hashimoto's, they walked and supported me through a detailed plan of recovery. The team at Root Functional Medicine help you treat issues at the source instead of just treating the symptoms. They focus on all areas of your life that contribute to your heath: sleep, stress, diet, supplementation and exercise. It's a long road to recovery but worth the journey! Within a month I saw a dramatic reduction in my symptoms and over time they continue to improve. Thank-you!


After a year and a half of struggling through failed infertility treatments, our RE recommended we move to IVF. A big expense, we decided to stop all treatment until we could save enough for it-we we’re estimating a few years until we could. In the interim, I decided to see what I could do to treat my PCOS and prepare my body to be more receptive.
Right away, Kelsey and Dr. Erica pinpointed insulin resistance (I’ve been telling traditional doctors for 7 years that I have this problem, nobody would test); among other items.
Kelsey tailored a PCOS friendly diet and supplement protocol and introduced me to some products designed specifically for PCOS.
After three months, my husband and I were IN SHOCK to find out I was pregnant. We were given a 4% chance of conceiving on our own.
Kelsey helped me to heal the root cause of my infertility. Fertility treatments are designed to make your body do a certain thing, instead of fixing the problem at hand. For anyone trying to conceive, Root is a must first step. I don’t know if we could have saved months of heartache (and so much money) if we had begun here—but I can’t help but equate my success to the lifestyle changes Kelsey helped me make. We are forever grateful to this team! You have given us a family!


I originally reached out to Root Functional Medicine for their PCOS program and began working with Kelsey. Mid-way thru my Rheumatoid Arthritis flares up to the point where I was struggling to walk and function. I immediately asked Kelsey if there was a food allergy test that could test for possible food allergies that my body reacts too and causes inflammation. Kelsey mentions the Leap/MRT program. I did the Leap/MRT blood test, followed the
eating plan she provided based on my results and started this in early April. I am now in my final phase of the Leap/MRT program and I am 99.9% pain free. I cannot thank Kelsey enough for her help and for helping me get my life back!


Dr. Armstrong pulled me out of a pretty bad health state, spent the time to get to know and understand me, and also gave me recommendations and a path that really changed my life. I've lost nearly 70 pounds now, my blood pressure is normal, and I'm living / eating way better than I ever have. I have more energy, I sleep better, I just overall feel better! Really all of the recommendations she gave me really opened my eyes - and quite frankly I feel helped to save my life... So very sincerely - thank you for saving me, and being the best doctor I've ever had.


I made the appointment to see Dr. Armstrong mainly to talk about my migraines, which had really gotten out of control (10+ per month). But I also wanted to talk to her about my thyroid disease, and my family history with autoimmune disease. I knew from filling out the online forms that I was going to like the approach of Dr. Armstrong, because the focus seemed to be on finding the underlying causes rather than just treating symptoms. Dr. Armstrong is a great communicator. She listened to my story and we came up with a plan together to help address my migraines and other concerns. I really loved the idea of thinking about nutrition, stress reduction and exercise as part of a treatment plan. At my second visit, my migraines were down by more than half, which in and of itself was fantastic, but I was (and continue to be) feeling super energetic and optimistic about my health. Dr. Armstrong keeps patients feeling like she is with them working on their plan for health, and I really appreciated that. My messages and questions were always answered immediately, and she always followed up with me. I’m 100% sold on the idea of functional medicine as the best approach to overall health. I recommend so strongly Dr. Armstrong! The results for me have really been life-changing and I am so happy that I made the decision to contact her.


When I first went to Root as a patient, I had recently lost 55 pounds and was feeling relatively healthy. Even though I had lost the weight and was feeling good I felt like there was something missing in my diet. I wasn't experiencing this overall sense of euphoria people describe after losing a lot of weight. Since starting a nutrition program three weeks ago, my anxiety has drastically decreased, my moods don't dip during the 2-4pm slump, I no longer have intense sugar cravings, and overall I feel healthier and happier! The information that I have received from Root has been invaluable and I highly recommend this program to anyone interested in improving their overall health.


Kelsey's advice has been very helpful in tweaking things for me and making this a long-term way of living not a quick fix or "diet". I'm excited about how the slight changes have kept me fuller longer and I don't feel as restricted as in the past.


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