Oral x Gut Axis Study

Help us better understand the connection between oral and gut health

Take part in a first-of-its-kind study by Bristle Health and Tiny Health. Receive both an oral and gut microbiome test at exclusive research pricing. By joining, you'll gain insights into your oral and gut health, and help our scientists better understand the connection.

Recruitment starts Oct 2025

For Adults 18+ (see criteria) (see criteria)

Location: United States
By Kimberley Sukhum, PhD and Dr. David Lin, PhD
Gut Health Test

People with gum disease are 2–3× more likely to develop gut conditions like IBD

Research has consistently shown that gum disease, which stems from an imbalanced oral microbiome, is linked to higher risk of gut conditions such as IBS and IBD. Yet despite this connection, oral health is rarely assessed in people with gut disorders. This study, led by Tiny Health and Bristle, aims to fill that gap by analyzing both oral and gut microbiomes together — to uncover patterns that could lead to earlier detection and better treatment options.

* Source: https://bmcoralhealth.biomedcentral.com/articles/10.1186/s12903-020-1053-5

Get a complete picture of your digestive and oral health

Get a complete picture of your digestive and oral health

By joining, you’ll gain comprehensive insights into both your oral and gut microbiomes — giving you a more complete view of your digestive health than either test alone. You’ll collect simple at-home samples and receive clear, personalized reports to help you improve your oral & gut health. Plus, your de-identified results will contribute to research exploring how oral bacteria may influence gut conditions, helping shape future care.

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Am I eligible to participate?

Inclusion criteria

You may be eligible to participate are 18 years or older.

Inclusion Criteria

  • You are eligible to participate if you are over 18 years old. You must be a resident of the US with US postal service (Excluding NY)
  • You must be a resident of the US with US postal service (Excluding NY)

Exclusion criteria

Exclusion Criteria:

  • Participants cannot have taken IV or oral antibiotics in the past 8 weeks. Participants cannot have had dental procedures (ex. cleaning or other in-office work) in the past 2 weeks.
  • Participants do not need to have a gut or oral condition. Healthy participants are encouraged to participate.

How to join the study

If you are interested, please complete the survey below and you will receive a link to purchase the Bristle Oral Health Test and Tiny Health Gut Health Test at research pricing.

Bristle & Tiny Health Bundle
$249
Retail value of $481. That's a savings of $232.
  • 1x Mess-free Tiny Health Gut Microbiome stool test to further understand how gut health relates to oral microbiome
    • Track essential bacteria that support oral health, metabolic health and fight inflammation
    • Gut Health Report with personalized recommendations (delivered in 2-3 weeks)
  • 1X Bristle Oral Health Saliva Test to get to the root cause of oral health issues
    • Identify the root cause of chronic bad breath, inflamed gums, tooth decay, gum recession and more.
    • Personalized results (delivered in 2-3 weeks)
Bristle Health Test
$100
Retail value of $282
  • 1X Bristle Oral Health Saliva Test to get to the root cause of oral health issues
    • Identify the root cause of chronic bad breath, inflamed gums, tooth decay, gum recession and more.
    • Personalized results (delivered in 2-3 weeks)

How to join the study

If you are interested, please complete the survey below and you will receive a link to purchase the Bristle Oral Health Test and Tiny Health Gut Health Test at research pricing.

Bristle & Tiny Health Bundle
$249
Retail value of $481. That's a savings of $232.
  • 1x Mess-free Tiny Health Gut Microbiome stool test to further understand how gut health relates to oral microbiome
    • Track essential bacteria that support oral health, metabolic health and fight inflammation
    • Gut Health Report with personalized recommendations (delivered in 2-3 weeks)
  • 1X Bristle Oral Health Saliva Test to get to the root cause of oral health issues
    • Identify the root cause of chronic bad breath, inflamed gums, tooth decay, gum recession and more.
    • Personalized results (delivered in 2-3 weeks)
Bristle Health Test
$100
Retail value of $282
  • 1X Bristle Oral Health Saliva Test to get to the root cause of oral health issues
    • Identify the root cause of chronic bad breath, inflamed gums, tooth decay, gum recession and more.
    • Personalized results (delivered in 2-3 weeks)

How to join the study

If you are interested, please complete the survey. If you qualify for the study, you will be directed toward a special purchase link to order your gut or vaginal test at the discounted rate.

About Tiny Health

Gut health for every age and every stage

Tiny Health is the first and only precision microbiome wellness platform designed for lifelong health — from the first 1,000 days to the last.

Founded in 2020 and built by microbiome scientists and physicians, Tiny Health uses shotgun metagenomics to deliver strain-level and functional microbiome insights. Its clinical-grade gut and vaginal tests help families and practitioners address the root causes of many chronic conditions with evidence-based interventions. Trusted by over 80,000 people worldwide, Tiny Health is redefining the microbiome as a cornerstone of personalized wellness

Hands holding microbiome test tube with graphs showing immune strength and antibiotic resistance data
About Bristle Health

Bristle Health helps you find & fix the root cause of oral health problems

Bristle Health provides at‑home oral microbiome testing and guidance to help people understand their oral health and how to resolve symptoms like bad breath, gum inflammation, tooth decay, and more with evidence-backed recommendations.

How does the Research Edition work?

How does the research edition work?

  • Apply for the study and purchase your kits
  • Complete the qualification survey via the button on this page to see if you qualify, then purchase the Oral and Gut microbiome tests.
  • Both tests will be mailed to you, where you can collect your two samples at-home and mail them back to our respective labs with pre-paid shipping envelopes.
  • You will fill out health history and sample surveys upon sampling.

Send in your sample

a circle icon with the number 3

Receive oral and gut test results

  • Receive actionable, and evidence-based recommendations to help understand your health and course-correct oral and gut imbalances
  • The microbiome result report and action plan are a part of the regular Bristle Health and Tiny Health Gut Test product and not associated with the research study.

How do we look at the microbiome?

High resolution analysis

We use shotgun metagenomics, a technology used in microbiome research. Make informed decisions with a comprehensive list of microbes found in your sample.

Functional insights

Through functional profiling, we tell you what microbes are present, how much of them are there, and what they’re actually doing.

Targeted suggestions

Get actionable advice tailored to your age and unique test results. Our at-home tests empower you with strain-level detail and precision science.

Your privacy comes first

We are dedicated to safeguarding your personal information at every turn and we will never sell your personal information.  Your data is encrypted with high security standards to ensure complete confidentiality.

CLIA & CAP certified lab

Your samples are processed at a U.S. clinical-grade lab to ensure the accuracy, reliability, and timeliness of test results.

Meet our supporters:

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Medical Advisors

Dr. Elisa Song, MD
Chief Medical Officer

Integrative Pediatrician and Pediatric Functional Medicine Expert
Founder, Healthy Kids Happy Kids

Dr. Emeran Mayer, MD
Medical Advisor

Executive director, G. Oppenheimer Center for Neurobiology of Stress and Resilience, UCLA; Author of The Mind-Gut Connection

Dr Qian Yuan, MD, PhD, FAAP
Medical Advisor

Demarest Lloyd Jr Endowed Chair in Food Allergies;  Senior Pediatrician, Pediatric Gastroenterology and Nutrition, Co-Director of Food Allergy Center, Massachusetts General Hospital; Associate Professor in Pediatrics, Harvard Medical School

Ruben Mars, PhD
Founding Advisor

Ruben Mars is an Assistant Professor of Medicine at Mayo Clinic in Rochester, Minnesota.

Noel Mueller, PhD
Scientific Advisor

Associate Professor of Epidemiology, Johns Hopkins University

Meghan Azad, PhD
Scientific Advisor

Associate Professor of Pediatrics and Child Health at the University of Manitoba; Co-Director, Manitoba Interdisciplinary Lactation Center (MILC); Deputy Director, CHILD Cohort Study

Joel Warsh, MD
Medical Advisor

Board-Certified Pediatrician, Creator of Raising Amazing Podcast

Nicole Calloway Rankins, MD, MPH
Medical Advisor

Medical Advisor; Practicing OB/GYN Hospitalist Physician, Creator and Host of The All About Pregnancy & Birth Podcast

Dr. Kim Green, MD
Medical Advisor

Associate Clinical Professor, UCSF; Pediatrician and former Chief Innovation Officer, Kaiser Permanente

Interested? Join this study

If you are interested, please complete the survey. Qualified individuals will be contacted by the study coordinator to provide consent and enroll in the study.

Frequently Asked Questions

What is the cost and time commitment?

There is no cost to participation. You must be capable of taking two microbiome stool samples and filling out two surveys online. Collecting a microbiome sample can be done on your own time, at home, and should take a few minutes. Each of the surveys can take anywhere between 5-15 minutes to complete, depending on the complexity of your answers. The total duration of the study is meant to conclude after taking the supplement for 30 days and completing your second sample and exit survey.

What do I get for participating?

You will receive a Bristle Oral Microbiome and Tiny Health Gut Health Tests (estimated value $TBD) and your personalized reports from each test.