Dr. Sarah Khan, PhD, MBA · Integrative & Functional Nutrition
Online Functional Nutritionist for Gut, Thyroid, and Autoimmune Health
Your labs keep coming back normal, but you still feel awful. I work virtually with clients across the United States to find what is actually driving your symptoms, then build a plan around your biology instead of a generic template.
Not sure where to start? Take the free 2-minute Root Cause Quiz
PhD, Integrative & Functional Nutrition
5.0 on Google · 21 five-star reviews
Clients seen virtually nationwide
You do not need to live in New York to get real answers
Most people who find me have already seen several practitioners. They have been told everything looks fine. They have tried elimination diets, probiotics, and a cabinet full of supplements, and they still feel exhausted, bloated, foggy, or inflamed.
The problem is almost never a missing supplement. It is that no one has asked why your body is responding this way. That question does not require us to be in the same room.
This is usually the pattern
Bone-deep fatigue
Exhausted no matter how much you sleep. Wired and depleted at the same time.
Digestion that runs your life
Bloating, IBS, or reacting to foods you used to tolerate without a thought.
Brain fog that will not lift
Focus takes effort it never used to, and the words are not there when you need them.
Hormones that feel off
Cycles, mood, sleep, or weight shifting, and nothing you try seems to move them.
Autoimmune flares
Managing a condition and quietly planning your life around the next flare.
Normal labs, no answers
Everything comes back in range and you are tired of being told you are fine.
What working together online actually looks like
Same depth, same concierge access, no commute.
Step 01
Comprehensive Assessment
You complete a detailed intake covering your health history, major life events, current diet, medications, and daily routines. I review every lab you already have before we ever meet.
Step 02
Your Personalized Protocol
We meet by video for an in-depth review. You leave with a sequenced nutrition and lifestyle plan built around your biology and your actual schedule, plus a written guide to implement it.
Step 03
Ongoing Refinement
Between sessions you have direct access to me for questions and real-time adjustments. Healing is rarely linear, so we track, retest when it helps, and adjust as we go.
What I work on with virtual clients
These overlap far more than most people realize, which is often why earlier attempts did not hold.
SIBO and IMO
Hydrogen, methane, and hydrogen sulfide overgrowth. Breath testing ships to you at home anywhere in the country.
Gut Health and IBS
Bloating, reflux, food sensitivities, and irregular digestion that a restrictive diet alone never resolved.
Hashimoto’s and Thyroid
Fatigue, hair loss, and rising antibodies, addressed through the gut, blood sugar, and nutrient status driving them.
Autoimmune Disease
Fewer flares and a body that feels stable again, by looking at the systems driving immune activity.
Hormone Imbalances
Hormone symptoms are usually downstream of blood sugar, gut function, liver health, and stress physiology.
Perimenopause
Weight, mood, sleep, and energy shifts in your 30s and 40s that do not match what you are doing.
Based in New York and prefer to be seen in person? See the Manhattan functional nutrition practice.
Does online functional nutrition work as well as in person?
In this work, yes. Functional nutrition is built on your history, your symptom timeline, your labs, and how your systems interact. All of that travels perfectly well over video. There is no physical exam that changes the plan, and I am not diagnosing disease or adjusting your medications. That stays with your physician.
What actually determines results is the depth of the assessment and the quality of the follow-up. Virtual clients get the same comprehensive intake, the same lab interpretation, and the same concierge access between sessions as anyone I see at my Manhattan office.
Functional testing ships to your door
When testing adds clarity, at-home collection kits are mailed to you anywhere in the country. That includes SIBO and IMO breath testing, comprehensive stool testing, full thyroid panels, and hormone testing. You collect at home, the lab processes it, and we review the results together on video.
I use testing to confirm what your symptoms are already pointing toward and to make your plan more precise, never to order for its own sake. You will not be left with a printout and no direction.
Who you are working with
Dr. Sarah Khan, PhD, MBA
I hold a PhD in Integrative and Functional Nutrition from Saybrook University, where my dissertation examined inflammatory markers in thyroid conditions, along with an MBA from Long Island University and a BS in Community Health and Biology from Hofstra University. I founded Sarah Integrative and Functional Nutrition in 2024 as a concierge practice at 136 Madison Avenue in Manhattan, and I now see clients both in the office and virtually across the country.
My approach is root cause and systems based. Rather than treating gut, thyroid, hormone, and immune symptoms as separate problems, I look at how they drive one another, which is usually where earlier attempts stalled. More about my background and approach.
This page is educational and is not medical advice. Functional nutrition complements your medical care and does not replace diagnosis or treatment from your physician.
What clients say
★★★★★ 5.0 on Google · 21 five-star reviews
★★★★★
“In 20 years of dealing with health issues, I have never found someone more willing to help me find relief.”
She approaches each client dimensionally and offers life-changing solutions for every aspect of health. I had often felt left on an island by conventional medicine. Now I have someone in the trenches with me.
Alisha R.
★★★★★
“As a skeptic, I was relieved by the scientific, detailed explanations she provided.”
Sarah gave me extremely personalized advice and created a safe space to discuss my health in detail. She truly listens and encourages diverse, expert ways to tackle health concerns.
Aditya A.
★★★★★
“It is so reassuring to finally know exactly what is going on with my body.”
It is hard having sleep issues and getting no answers from doctors, but Sarah knows exactly what to pinpoint and improve. She is also extremely kind and empathetic.
Nathan A.
Ready to stop guessing?
Book a free discovery call and we will talk through what you have been experiencing, whether we are a good fit, and what the right level of support looks like. Wherever you are in the country.
Not ready to book? Start with the free 2-minute Root Cause Quiz
Dr. Sarah Khan, PhD, MBA · Integrative & Functional Nutrition
136 Madison Avenue, New York, NY 10016 · Seeing clients virtually nationwide