Microbiome AnalysisBREAKNCT06954675
Comparison of Microbiome Changes in Healthy Adults Following Ketone Ester Consumption
A study testing Exogenous ketone ester in people with Microbiome Analysis, run by University of California, San Francisco at 1 site in United States.
Trial summary
The goal of this observational study is to learn if a ketone ester can improve the content of the gut microbiome. The main questions it aims to answer are: Does a ketone ester reduce age-related signatures in the gut microbiome? What changes occur in the gut microbiome after consuming a ketone ester? Participants… Read more about this study
- Who is it for?
- Ages 18 to 40 yearsHealthy volunteers can take part
- Conditions the study is for
- Microbiome Analysis
- What is being tested?
- Exogenous ketone ester
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 20 participants
- Where
- 1 siteUnited States
- Study dates
- 21 Nov 2025to 30 Oct 2026
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 40 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Subject is male or female, 18 to 40 years of age, inclusive, at Virtual Visit 1.
- Subject has a self-reported BMI of 18.5 to 39.9 kg/m2 (inclusive) at Virtual Visit 1.
- Subject is willing and able to comply with all study procedures including maintenance of habitual dietary intake, consumption of study product at specified intervals, written questionnaires including study log and beverage tolerability questionnaire (KETQ), habitual exercise and medication and supplement use.
- Subject has an email address and internet access via computer, phone, or other device, and is willing and able to maintain internet access throughout the trial to complete virtual visits via video conference.
- Subject has no health conditions that would prevent them from fulfilling the study requirements as judged by the Study Clinician on the basis of medical history.
- Subject understands the study procedures and signs forms providing informed consent to participate in the study.
Who cannot join
- Subject is unable to converse in English or Spanish
- Subject is unable to provide informed consent due to cognitive impairment or insufficient English or Spanish language comprehension
- Subject has been hospitalized within 30 days of Virtual Visit 1.
- Subject has a history or presence of uncontrolled and/or clinically active pulmonary, cardiac (e.g. >= New York Heart Association class III), hepatic, renal, endocrine (including type 1 diabetes), hematologic, immunologic, neurologic (e.g., Alzheimer's or Parkinson's diseases), psychiatric (including unstable depression and/or anxiety disorders) or biliary disorders. Stable chronic disease is not an exclusion criterion unless specified.
- Subject has a clinically important gastrointestinal condition that would potentially interfere with the evaluation of the study beverage [e.g., inflammatory bowel disease, irritable bowel syndrome, chronic constipation, severe constipation (in the opinion of the Study Clinician), history of frequent diarrhea, history of surgery for weight loss, gastroparesis, systemic disease that might affect gut motility according to the Study Clinician, reflux requiring daily medication, history of gastrointestinal ulcers or bleeding, celiac disease, and/or clinically important lactose intolerance].
- Subject has a known allergy, intolerance, or sensitivity to any of the ingredients in the study product, including milk protein.
Show all 13Show fewer
- Subject is undergoing treatment or active surveillance for cancer, or has been diagnosed with cancer in the prior two years, except for non-melanoma skin cancer.
- Subject has recently used antibiotics within 60 days of Virtual Visit 1.
- Subject has extreme dietary habits (e.g., intermittent fasting or time restricted eating, Atkins diet, vegan, very high protein/low carbohydrate or has used weight-loss medications (including over-the-counter medications and/or supplements) or programs within 30 days of Virtual Visit 1.
- Subject has used medications (over-the-counter or prescription) known to influence gastrointestinal function including, but not limited to, opioids, weight loss medications, antidiarrheals, and antispasmodics) within 30 days of Virtual Visit 1.
- Subject has used ketone supplements (ketone salts or esters, and medium chain triglycerides [MCT]) within 30 days of Virtual Visit 1.
- Subject is a female who is pregnant, planning to be pregnant during the study period, lactating, or is of childbearing potential and is unwilling to commit to the use of a medically approved form of contraception throughout the study period. The method of contraception must be recorded.
- Subject has a condition the Study Clinician believes would interfere with their ability to provide informed consent, comply with the study protocol, which might confound the interpretation of the study results, or put the subject at undue risk.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site, 1 recruiting
- Recruiting
UCSF Wayne and Gladys Valley Center for Vision
San Francisco, California, 94158
Sidharth S Madhavan, PhD, 248-797-1025, sidharth.madhavan@ucsf.edu
John C Newman, MD, PhD
About this study
Official title: Bacterial Responses to Enteric Alterations After Ketones
The goal of this observational study is to learn if a ketone ester can improve the content of the gut microbiome. The main questions it aims to answer are:
- Does a ketone ester reduce age-related signatures in the gut microbiome?
- What changes occur in the gut microbiome after consuming a ketone ester?
Participants will:
- Take a ketone ester every day for seven (7) days
- Collect and ship stool samples within seven (7) days before, during, and within seven (7) days after the study period
- Measure their ketone levels with a urine strip every day after having the drink
- Answer questions about their typical diet on a normal day
- Record their symptoms, if any arise
- Conditions
- Microbiome Analysis
- Being tested
- Exogenous ketone ester
- Keywords
- Microbiome, Exogenous ketone, Ketone ester
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Exogenous ketone esterDietary supplement
25g Bis-octanoyl-(R)-1,3-butanediol (C8)
| Study group | Role | What they receive |
|---|---|---|
| 25g Bis-octanoyl-(R)-1,3-butanediol (C8) | Experimental | Participants will receive 25g of the ketone ester bis-octanoyl-(R)-1,3-butanediol (C8) daily. Receives: Dietary Supplement: Exogenous ketone ester |
What is being measured
The primary outcome is the main question the study is designed to answer.
Longitudinal Change in Microbiome Composition
Microbiome composition will be defined as the following components: 1) alpha-diversity as calculated by Shannon Index; 2) beta-diversity; and 3) microbial community taxa and gene number.
Measured: From baseline sampling to final sampling, including intervention period, at 21 days
Secondary outcomes (1)
Acute Tolerability Symptoms related to Product Ingestion
Symptoms will be assessed daily using a standardized Beverage Tolerability Questionnaire (Stubbs et al. J Nutr Health Aging 2024). Symptoms are rated on a scale of mild, moderate, and severe with the following symptoms: 1) gas/flatulence; 2) nausea; 3) vomiting; 4) abdominal cramping; 5) stomach rumbling; 6) burping; 7) reflux/heartburn; 8) diarrhea; 9) headache; and 10) dizziness.
Measured: From start to end of intervention at 7 days
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted1 May 2025
- Study start21 Nov 2025
- Primary completion30 Oct 2026 (estimated)
- Study completion30 Oct 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Microbiome AnalysisStudies of the same condition, open and under way.
- More trials run by University of California, San FranciscoThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 20 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of California, San Francisco
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- John C Newman, MD, PhD, Principal investigator, University of California, San Francisco
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06954675
- Sponsor's protocol ID
- 25-43835
- Acronym
- BREAK
- Status last verified
- Sep 2026
- First submitted
- 11 Apr 2025
- Last updated
- 24 Sep 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: This is a pilot study that will only be used to inform future trial design, no IPD will be shared externally.
Study at a glance
From the registry record, last updated by the sponsor on 24 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Bacterial Responses to Enteric Alterations After Ketones
- ClinicalTrials.gov ID
- NCT06954675
- Acronym / sponsor ID
- BREAK / 25-43835
- Conditions
- Microbiome Analysis
- Keywords
- Microbiome, Exogenous ketone, Ketone ester
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 20 participants (estimated)
- Lead sponsor
- University of California, San FranciscoUniversity, hospital or other
- Study start
- 21 Nov 2025 (actual)
- Primary completion
- 30 Oct 2026 (estimated)
- Study completion
- 30 Oct 2026 (estimated)
- First posted
- 1 May 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The goal of this observational study is to learn if a ketone ester can improve the content of the gut microbiome. The main questions it aims to answer are:
- Does a ketone ester reduce age-related signatures in the gut microbiome?
- What changes occur in the gut microbiome after consuming a ketone ester?
Participants will:
- Take a ketone ester every day for seven (7) days
- Collect and ship stool samples within seven (7) days before, during, and within seven (7) days after the study period
- Measure their ketone levels with a urine strip every day after having the drink
- Answer questions about their typical diet on a normal day
- Record their symptoms, if any arise
Study design
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| 25g Bis-octanoyl-(R)-1,3-butanediol (C8) | Experimental | Dietary Supplement: Exogenous ketone esterParticipants will receive 25g of the ketone ester bis-octanoyl-(R)-1,3-butanediol (C8) daily. |
Who may qualify
- Ages
- 18 to 40 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (6 listed)
- Subject is male or female, 18 to 40 years of age, inclusive, at Virtual Visit 1.
- Subject has a self-reported BMI of 18.5 to 39.9 kg/m2 (inclusive) at Virtual Visit 1.
- Subject is willing and able to comply with all study procedures including maintenance of habitual dietary intake, consumption of study product at specified intervals, written questionnaires including study log and beverage tolerability questionnaire (KETQ), habitual exercise and medication and supplement use.
- Subject has an email address and internet access via computer, phone, or other device, and is willing and able to maintain internet access throughout the trial to complete virtual visits via video conference.
- Subject has no health conditions that would prevent them from fulfilling the study requirements as judged by the Study Clinician on the basis of medical history.
Key exclusion criteria (13 listed)
- Subject is unable to converse in English or Spanish
- Subject is unable to provide informed consent due to cognitive impairment or insufficient English or Spanish language comprehension
- Subject has been hospitalized within 30 days of Virtual Visit 1.
- Subject has a history or presence of uncontrolled and/or clinically active pulmonary, cardiac (e.g. >= New York Heart Association class III), hepatic, renal, endocrine (including type 1 diabetes), hematologic, immunologic, neurologic (e.g., Alzheimer's or Parkinson's diseases), psychiatric (including unstable depression and/or anxiety disorders) or biliary disorders. Stable chronic disease is not an exclusion criterion unless specified.
- Subject has a clinically important gastrointestinal condition that would potentially interfere with the evaluation of the study beverage [e.g., inflammatory bowel disease, irritable bowel syndrome, chronic constipation, severe constipation (in the opinion of the Study Clinician), history of frequent diarrhea, history of surgery for weight loss, gastroparesis, systemic disease that might affect gut motility according to the Study Clinician, reflux requiring daily medication, history of gastrointestinal ulcers or bleeding, celiac disease, and/or clinically important lactose intolerance].
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Exogenous ketone ester25g Bis-octanoyl-(R)-1,3-butanediol (C8) | Dietary supplement | 25g Bis-octanoyl-(R)-1,3-butanediol (C8) |
Primary outcome
Longitudinal Change in Microbiome Composition
Time frame: From baseline sampling to final sampling, including intervention period, at 21 days
Microbiome composition will be defined as the following components: 1) alpha-diversity as calculated by Shannon Index; 2) beta-diversity; and 3) microbial community taxa and gene number.
1 secondary outcome
Acute Tolerability Symptoms related to Product Ingestion
Time frame: From start to end of intervention at 7 days
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 24 Sep 2026.
- Individual participant dataSharing planned: No. This is a pilot study that will only be used to inform future trial design, no IPD will be shared externally.
Related trials for Microbiome Analysis
RecruitingObservational study
Sample Collection From Healthy Volunteers for Assay Optimization
Healthy Volunteers
Active, not recruitingObservational study
Antibiotic Resistance Genes in Periodontitis
Periodontal Disease, Periodontitis
Active, not recruitingObservational study
Microbiome Characterization in Fatty Pancreas
Fatty Pancreas, Microbiome Analysis
Not yet recruitingObservational study
Sepsis ICU Gut Microbiome Analysis
Sepsis, Septic Shock
Active, not recruiting
Probiotics in Adults With Rheumatoid Arthritis
Rheumatoid Arthritis (RA)
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
John C Newman, MD, PhD principal investigator
University of California, San Francisco
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Exogenous ketone ester in people with Microbiome Analysis, run by University of California, San Francisco at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 13 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 24 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Sidharth S Madhavan, PhD (248-797-1025, sidharth.madhavan@ucsf.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Longitudinal Change in Microbiome Composition (time frame: From baseline sampling to final sampling, including intervention period, at 21 days). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 24 Sep 2026.