About Second Opinion Physician

Second Opinion Physician offers lab testing and medical consultations to assess potential biochemical imbalances that may contribute to mood or behavior disorders, using the Walsh Approach as a guide. Various lab panels and consultation options are available for initial and re-testing evaluation of mood, behavior, and general health disorders.

David Epstein, D.O. is the manager and sole practitioner operating Second Opinion Physician, P.C. and this HIPAA compliant website. Dr Dave is a trained “Walsh Practitioner” and a telehealth care provider with an extensive background in Functional Medicine.

The Walsh Approach is evaluation method developed by Dr. William Walsh, PhD, that aims to address biochemical imbalances in the body that may contribute to mood or behavior disorders, including depression, anxiety, OCD, ODD, BPD, ADHD, and schizophrenia. This approach involves the use of laboratory testing, questionnaire review, to identify potential imbalances and develop a treatment plan that may include the use of nutritional supplements.

Functional medicine is a holistic approach to healthcare that focuses on identifying and addressing the root cause of health issues, rather than just treating the symptoms. It considers the interconnections between different systems in the body and the impact of lifestyle and environmental factors on overall health.

While Dr Epstein is a fully licensed osteopathic physician, this is a telemedicine practice which has limitations in patient management. It is always important to work with a local qualified practitioner when managing prescription medicines and acute health urgencies.

second opinion physician

Focus on the Walsh Approach

Dr. Walsh is an internationally recognized expert in the field of mental disorders and a key scientist paving the way for orthomolecular psychiatry and nutritional medicine.  Over the past 30 years, Walsh has developed biochemical test protocol and supplement plans to optimize the nutrients associated with neurotransmitter production and activity. Through his non-profit research institute, Walsh Research Institute he has sampled and evaluated tens of thousands of cases and datapoints from patients in and around Chicago and the Cook County hospital and prison systems.  His work is applicable to the majority of major mood disorders including severe depression, bipolar disorder, anxiety, shizophrenia, psychosis, post partum depression as well as less severe though very important conditions of insomnia, ADHD, OCD, ODD, Autism, dementia, Alzheimer’s and other disorders that are prescribed pharmacutical medicines almost exclusively, worldwide.

Dr Walsh’s book, Nutrient Power: Heal Your Biochemistry and Heal Your Brain , succinctly describes his evidence-based theory and protocol.  Many of his interviews and podcasts can be seen on our website. According to Dr Walsh, as many as 95% persons, suffering from all types of mood and behavior disorders, fall into one or more of the Five Biotype of Depression. These biochemical imbalances are referred to as Overmethylation, Undermethylation, Copper Overload, Pyrrole Disorder and Toxic Overload.

Second Opinion Physician Founder

With a career long (35 years) dedication to treating health conditions with natural alternatives to pharmaceuticals, my practice... and life, took a step forward the moment I met William Walsh PhD at an ACAM (American College of Advancement in Medicine) conference in 2014. His hands-on experience, scientific acumen, many years of dedication and wonderful grandfatherly kindness won my confidence and determination to study the basis of his theory. After attending my first Walsh-practitioners workshop, I was convinced that doctors finally have a great clinical opportunity to best identify and manage mood and behavior disorders naturally.

In my own career I owned and operated a neighborhood medical clinic in Atlanta with emphasis on EDTA chelation, IV vitamins and oxidative therapy. In the years that followed, I practiced as a medical consultant, opened two unrelated but similarly-oriented businesses, and started a Telemedicine practice and online supplements store dedicated to the Walsh approach to treating mood disorders.

Having now treated several hundred patients with this approach, it is my opinion that the 5 Biotypes of Depression concept developed by Dr Walsh's is a simplified explanation of the eloquent role that nutrients play in mental disorders. This understanding gives practitioners and patients an actionable understanding of the predominant biochemical causes of neurotransmitter imbalance; nutrient imbalances, epigenetics and oxidative stress. My practice experience has affirmed this approach applicable to a wide array of childhood and adult mental issues. To further protect the aging population against the risks of Alzheimers and dementia, the Walsh protocol is complimented by the Dale Bredesen, M.D. model. Bredesen's test evaluates additional biochemical imbalances that are paramount when it comes to brain preservation and risk reduction. Lifestyle, dietary, nutritional, hormonal, genetic and digestive well being are the greatest influences on our vitality and longevity that we could ever come to understand.

I am overjoyed by the success of this protocol and pleased to be able to offer it, online, with the conveniences and operational efficiency that is possible by utilizing the telemedicine platform.


David Epstein DO Physician
Dr. David Epstein, D.O.
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Patient and Attorney Testimonials

My 22-year old daughter was hospitalized in a mental facility in November 2018. She was a nursing student and was the life of the party; no issues. Then all of a sudden I started to notice some things she would said just didn’t make sense. She had what I thought was a panic attack and said she wanted to kill herself and would have blank emotionless stares. So, I immediately took her to the emergency room in which they admitted her with a 72-hour hold in a psychiatric facility. I was devasted. I didn’t know what the outcome would be.

After a couple of days the physicians finally diagnosed her with schizoaffective disorder and bipolar disorder. I was devastated and started to read every single book I could find on schizophrenia, schizoaffective disorder and bipolar disorder. I would read and not even get any sleep or eat anything because I was determined to understand this disease. I remember reading an article where an individual diagnosed with a mental health condition said that “orthomolecular” psychiatry is what helped him to cope along with maintaining a good diet. I had never heard that term before. So, I immediately looked up the term and came across a book written by A. Hoffer called “Orthomolecular Treatment for Schizophrenia.” I ordered the book and read the 55-page book as soon as I got it. In the meantime, my daughter is now on day 4 in the psychiatric hospital. When I read the book, Dr. Hoffer’s approach of using vitamins and supplements and nutritional strategies to help with this disease all made sense to me. It made sense because I was myself already on a natural healing journey with some of my physical ailments of migraine headaches, anemia, acne etc. and vitamins and supplements and eating a wholefood organic diet cleared all of that up. I had seen it work in myself and started thinking….I have clear personal evidence that this has worked for my “physical” chronic issues, so how come the same approach can’t work for my daughter’s “mental” issues? I realized that the physical body and the brain are NOT disconnected but are one in the same. The more I read about the Gut-Brain connection and also Dr. William Walsh’s book called “Nutrient Power,” a light bulb went off and I just wanted to get my daughter out of that hospital immediately, so she could be home where I could help her.  

I immediately began to look for a physician in my area who specialized in the Walsh Protocol and came across Dr. Epstein. Just looking on his website and the content of his blog I knew that I was in the right place. I contacted Dr. Epstein through his online chat and he responded immediately. I was shocked to even find him available. But I believe that Dr. Epstein truly understands that anyone contacting him is in desperate and dire need and because of that makes himself available. I explained to him my daughter’s situation and he immediately had a plan of action. I was in tears.

The physicians at the psychiatric hospital never even spoke to me, let alone had a plan of action for how I can help my daughter. They only prescribed her antipsychotic drugs of Abilify and Lithium and sent her home on day 7. We completed several tests recommended by Dr. Epstein January 2019 and sure enough the results came back that she had pyroluria, copper overload, vitamin D deficiency and was undermethylated but Dr. Epstein immediately had a plan in place and emailed and discussed with me the protocol. I followed everything he said. It was a struggle at first to get my daughter to comply. She came home with 1200 mg of Lithium and 10 mg of Abilify to take everyday from the physicians at the psychiatric hospital. After I started Dr. Epstein’s protocol, he said that I may be able to titrate the medication down during this process. We started to see results in about 2 months.

My daughter used to sit and stare at the wall and cry for hours or sit with an emotionless gaze for hours. She would also throw herself down the stairs amongst other things. But in the first 2 months those behaviors ceased. So I took off 300 mg of the Lithium and 5 mg of the Abilify. I was afraid that symptoms might return but they did not. I continued the vitamin regimen for another 2 months and she started doing even better. I was amazed. She was able to now hold conversations with me and her siblings. She begin to care about her hygiene and wanting to do her hair and nails again. I was ecstatic.

Then I decided to take off another 300 mg of the Lithium bringing her down to 600 mg of Lithium. During this time I took off the other 5 mg of Abilify. She was now only taking 600 mg of Lithium and no Abilify at all. She still continued to progress. About 2 months later she applied for a job online working for a customer service company, which I though was an intense feat because she was holding complex conversations with real people and was enjoying it and getting paid. She had a new found desire to cook and be a chef and was making all sorts of gourmet dishes for the family. She had already been driving her car again for about 3 months and drove to a restaurant that she liked and asked them if they were hiring and they hired her on the spot. She came home excited and said she even renegotiated her pay for an extra $2 per hour. My daughter is living her life again and enjoying time again with family and friends. She was able to join us for a family gathering with friends and was able to hold conversations with everyone instead of retreating to her room due to anxiety like before.

I am truly grateful to Dr. Epstein and the Walsh Protocol without him, my daughter would be another statistic going in and out of the mental health facility without any recovery in sight. I can’t thank you enough Dr. Epstein.

Leona L.

Dr. Epstein’s Walsh approach for treating Depression is God send! My 15 year old son was diagnosed with bi-polar by a psychiatrist and medicated heavily with multiple medications for over 2 years, and wasn’t getting better. The therapist finally figured out he did not have bi-polar, but was depressed with OCD. Also, his body could not process folic acid! After a lot of research, I found the Walsh approach. I wanted to find a functional medicine doctor that practiced his approach, when Dr. Epstein’s web page appeared. We ordered the Comprehensive Biotype lab, he was diagnosed with undermethylation and leaky gut. Dr. Epstein prescribed several supplements, and my son, so far, isn’t experiencing depression. Thank you Dr. Epstein!

Helena D.

David has a reputation as the pre-eminent expert on biochemistry in this area and was referred to me by someone I think highly of as well.  The biochemical basis for mental health, and the interplay between it and criminal behavior is a fresh approach to criminal defense.  David was very effective in his presentation of information during the hearing on this subject.  He made difficult concepts understandable for the judge. He was patient in preparation beforehand.  I received positive feedback from other professionals who heard the case.   

Chandelle Summer, Esq.

Summer Law Firm

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Hello Dr. Epstein

My daughter is doing soooooo much better with the 5 months of treatment you recommended. With new she is 100% her normal self. However, the final piece remaining is she has a lot of anxiety around other people and doesn't want to interact with anyone outside our family. 

I would like to retest and see what the data looks like now. What retesting do you recommend and what is the cost for each? I was thinking I would like to retest the methylation panel, copper, pyrroles and vitamins D.

Please let me know your thoughts when you get the chance. It will he 6 months beginning Aug 6th

Thank you soooooo much!!



Dr. Epstein,

I can't thank you enough for saving my daughters life. She is back in Ballet, active in School and with friends; she wants to get involved with more than she can handle and wear herself out. I'm looking forward to getting an assessment done on myself very soon. 

Ramona C

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Dr. Epstein, Thank You so much!!! I have finally gotten to an optimal state of cognitive health. Your tailored supplements have given me a sense of wellbeing which I never had. I always suffered from ADD and for few years, took Adderall. The Adderall kept me dependent, and at best, masked the symptoms. Following your recommendation, I no longer need Adderall. My ADD symptoms are being addressed in a proper way. Read More


Patient of Dr Dave


Dr Dave is a talented compassionate integrative physician. He places his patients 1st and utilizes cutting edge therapies that help patients regain optimal health. I enjoyed working along side him and I highly endorse his clinical skills. Not only do I recommend that patients see him but I myself as an integrative physician would consult with him about my own healthcare needs. Read More

Gez Agolli NMD, PhD, DrPH

Managing Director at Progressive Medical Center

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Dr. Epstein came to our community as a family practice physician in the late 80s. I noticed that he was an osteopath, with a respectful, holistic approach to treating the body. Our community was so grateful that he chose to be our doctor.  It was the birth of my son that made me question the medical model of treating symptoms in the body rather than supporting our bodies so they in turn are able to take care of us. Read More

Anita B.

Patient of Dr Dave

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Hello Dr. Epstein,

Richard's health has really turned around!  His anxiety is gone, he has energy again, and his pain has lessened dramatically!  He is living his life learning to drive, looking for work and being out in public with no fatigue!  It's amazing! Thanks so much for you knowledge and help!

Sandy P


I became a patient of Dr. David Epstein roughly 2 months ago. I was in terrible shape at the time. I was suicidal, suffering from multiple anxiety disorders, PTSD and OCD. I found Dr. Epstein to be wonderful from the start. He ordered my blood and urine tests right away and as soon as all the results were in he started my on my Walsh Protocol. It has been 2 months now and I am no longer suicidal and depressed. My anxiety has been greatly reduced. My PTSD symptoms have improved along with my OCD symptoms. My energy is up and my sleep is sound. I urge anyone who is suffering from mental and emotional disorders not to hesitate and pick up the phone and call Dr. Epstein. He is by far the most caring and knowledgeable physician I have ever met, and there have been many. He encouraged me and he is always quick to answer e-mails with any questions I may have. I no longer feel like I live in the prison of Aspergers.
Thank you Dr. Epstein (and Dr. Walsh) - Your patient James from Florida

James B

Mood and Behavior Disorders Treated

Alcohol Abuse
Anger Management
Antisocial Personality
Asperger’s Syndrome
Autoimmune Disorders
Bipolar Disorder
Borderline Personality

Chronic Relapse
Developmental Disorders
Digestive Disorders
Drug Abuse
Eating Disorders
Emotional Disturbance
Learning Disabilities
Medication Management
Narcissistic Personality

Obsessive-Compulsive (OCD)
Oppositional Defiance
Oxidative Stress
Sleep or Insomnia
Substance Abuse
Suicidal Ideation
Trauma and PTSD
Weight Loss

Schedule a no-charge 'pre-consultation' with David Epstein, D.O.

Speak directly with our Walsh-trained physician to confirm the best approach for your unique situation.