AgingPhase 2ENGRAFTNCT07826793
Ecosystem Nourishment for Gut Restoration After Fecal Transplantation
A Phase 2 study testing Fecal Microbiota Transplant Capsules and Microbiome Rejuvenating Diet in people with Aging, run by Stanford University at 1 site in United States.
Trial summary
The purpose of this study is to test whether young-donor fecal microbiome transplantation (FMT) and a fermented, plant-rich high-fiber, microbiome rejuvenating diet (MRD) reduce inflammatory and biological aging markers. Read more about this study
- Who is it for?
- Ages 40 years and olderHealthy volunteers can take part
- Conditions the study is for
- Aging
- What is being tested?
- Fecal Microbiota Transplant Capsules and Microbiome Rejuvenating Diet
- Type of treatment
- Pill or oral medicine, Lifestyle or therapy programme
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 80 participants
- Where
- 1 siteUnited States
- Study dates
- Dec 2026to Jun 2028
- Phase
- Phase 2
- 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 40 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Able and willing to provide written informed consent prior to completion of any study procedures.
- Age ≥40 years at the time of consent.
- In generally good health, as determined by medical history, medication review, and investigator assessment.
- Willing and able to comply with all study procedures, assessments, and study-related restrictions for the duration of participation.
- Willing to adhere to the study's lifestyle considerations for the duration of the study (maintain usual diet unless assigned to the diet arm; maintain usual physical activity; avoid non-essential systemic antibiotics; avoid probiotic/prebiotic/synbiotic supplements).
- Willing and able to attend all required in-person study visits at Stanford University and complete remote assessments, if applicable.
Who cannot join
- Moderate or severe irritable bowel syndrome (IBS).
- Current or prior diagnosis of inflammatory bowel disease (IBD), including ulcerative colitis, Crohn's disease, or indeterminate colitis.
- Active gastrointestinal disease, including infectious gastroenteritis, colitis, gastritis, recurrent Clostridioides difficile infection, untreated Helicobacter pylori infection, or clinically significant malabsorption disorders (e.g., celiac disease).
- Major gastrointestinal surgery within the past 5 years (excluding cholecystectomy and appendectomy), or history of major bowel resection at any time.
- Body mass index (BMI) ≥40 kg/m².
- Diabetes mellitus.
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- Hyperthyroidism or uncontrolled hypothyroidism.
- Clinically significant renal disease.
- Clinically significant hepatic disease or significant liver enzyme abnormalities.
- Clinically significant cardiovascular disease.
- Autoimmune or systemic inflammatory disease.
- Current malignancy or history of malignancy within the past 5 years, excluding adequately treated non-melanoma skin cancer.
- Current use of immunosuppressive medications, including systemic corticosteroids, thiopurines, methotrexate, calcineurin inhibitors, biologic agents, or other immunosuppressive therapies.
- Receipt of fecal microbiota transplantation (FMT) within the previous 12 months.
- Use of systemic antibiotic therapy within 30 days prior to enrollment or anticipated antibiotic use during the study period.
- Use of probiotic supplements, prebiotic supplements, synbiotics, or live microbial therapeutics within 30 days prior to enrollment.
- Current use or use within the previous 6 months of medications prescribed primarily for weight loss.
- Current use of medications known to significantly affect body weight unless the medication and dose have remained stable for at least 6 months prior to enrollment.
- Neurodevelopmental, psychiatric, neurological, or neuromuscular disorders that, in the opinion of the investigator, may impair the participant's ability to provide informed consent, comply with study procedures, or complete study assessments.
- Current diagnosis of schizophrenia, bipolar disorder, or other severe psychiatric illness that may interfere with study participation.
- Current substance use disorder.
- Current smoking or nicotine use, including cigarettes, cigars, electronic cigarettes, vaping products, or nicotine replacement therapy.
- History of anaphylaxis or severe allergic reaction to study-related dietary components.
- Planned major dietary change, initiation of a structured weight-loss program, or initiation of a specialized therapeutic diet during the study period.
- Concurrent participation in another interventional clinical trial.
- Any other medical, psychiatric, or social condition that, in the opinion of the investigator, could compromise participant safety, study compliance, or interpretation of study outcomes.
- Pregnancy or breastfeeding
- Known immunodeficiency state, including HIV infection, primary immunodeficiency, active hematologic or solid-organ malignancy under treatment, or other clinically significant immunocompromise, independent of medication use.
- Dysphagia or any condition impairing the ability to swallow oral capsules.
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
Stanford University
Stanford, California, 94305
Sean P Spencer, MD PhD, 650-736-6555, seanspen@stanford.edu
Roujheen Sabetan, MPH, 650-498-8188, rsabetan@stanford.edu
About this study
The purpose of this study is to test whether young-donor fecal microbiome transplantation (FMT) and a fermented, plant-rich high-fiber, microbiome rejuvenating diet (MRD) reduce inflammatory and biological aging markers. Participants (≥40 years) will be randomized (1:1:1:1) for 8 weeks with 4-week follow-up to: (A) diet alone, (B) FMT alone, (C) diet + FMT, or (D) Placebo FMT. We will use rigorously screened young and healthy FMT donors and encapsulated delivery. Outcomes include change from baseline to end of dietary intervention (week 8) in markers of aging and inflammation. Secondary outcomes include defining microbiome engraftment/diversity/function, key metabolites, diet adherence, and quality-of-life.
Read the detailed description
For this study, the research participant will receive a once daily oral dose of healthy young FMT and diet modification to increase fiber and fermented food consumption. Throughout the study's duration, the participant will provide stool, blood and urine samples as well as a series of health questionnaires to track the impact of the intervention.
*PROTOCOL OVERVIEW* The study will begin with the selection of possible participants through the samples collected through the Stanford Microbiome Bank (IRB 85544), the participants identified will be contacted through the appropriate channels and asked to complete a short online questionnaire if interested in continuing with being a part of the protocol.After completing the questionnaire, those selected will be contacted via phone to schedule an in person appointment in the Clinical and Translational Research Unit (CTRU). During this appointment, the study team will obtain informed consent and one stool sample. Their initial stool sample will be sent outside Stanford for microbiome composition analysis which will determine if the participant is a good candidate for the protocol.
After enrollment in the protocol, the participants will be randomized in a 1:1:1:1 ratio to one of four study arms: Placebo, placebo + diet, FMT no diet, or FMT + diet. Those randomized to one of the FMT groups will be instructed to take a single oral dose of young FMT (4 capsules) for two weeks, and those randomized to a diet arm will have an initial appointment with the study's dietitian to establish a microbiome rejuvenating diet (MRD) starting with a one week ramp up period and continued for a total of 8 weeks. The main factors incorporated into the MRD will be ~3 servings/day fermented foods and ≥30-40 g/day or +20g fiber(plant-based whole food), 5g of resistant starch supplements and 5g of psyllium husk.
Throughout their enrollment in the protocol, the participants will provide stool samples weekly for analysis and complete general health and lifestyle questionnaires to assess protocol adherence and any changes in their health status. On weeks 0, 2, 4, 8 \& 12 participants will be asked to give a blood, urine and stool sample for further analysis and to complete a Nutrition Data System for Research (NDSR) questionnaire; stool is additionally collected at Week 6.
All patient samples will be coded and stored in Stanford facilities for further processing.
- Conditions
- Aging
- Being tested
- Fecal Microbiota Transplant Capsules, Microbiome Rejuvenating Diet, Placebo Fecal Microbiota Transplantation
- Keywords
- Fecal Microbiome Transplant, Aging, Young-donor FMT, Microbiome Rejuvenating Diet, Inflammaging, Gut Microbiome, DunedinPACE
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Fecal Microbiota Transplant CapsulesDrug
Also called FMT
Each dose (4 capsules) will be taken daily in the morning on an empty stomach. Clear liquids are allowed and regular breakfast can follow one hour later. If the dose is skipped, the missed dose should be skipped and the standard 4-capsule dose resumed the following morning; doses must not be doubled. There should be no solid food at the time of ingestion , solid food should be avoided at least 4 hours prior to ingestion of capsules, however, liquid diet is always allowed and a full glass of water should be taken after every dose ingestion. The treatment will be administered daily for 2 weeks.
Microbiome Rejuvenating DietBehavioural
Fiber intake: participants will be instructed to increase their fiber intake to >30/40g or +20g per day . There will be a 1 week ramp-up period in which participants will increase their intake progressively. Detailed instructions will be provided to include a variety of fiber sources (legumes, seeds, whole grains, nuts, vegetables, and fruits). Participants will also be instructed to include 5g of resistant starch supplements and 5g of psyllium husk in their diet.
Fermented food intake: participants will be instructed to add at least 3 portions of fermented food into their daily diet. There will be a 1 week ramp-up period in which participants will increase their intake progressively and maintain a high level of consumption for the following 8 weeks. Detailed instructions will be provided to include a variety of fermented foods (fermented dairy products, fermented vegetables, fermented non-alcoholic drinks, etc.).
Placebo Fecal Microbiota TransplantationOther
Participants will receive a once daily dose (4 pills) of inactive pills that are identical in size, shape, color, taste and feel to the active FMT pills
| Study group | Role | What they receive |
|---|---|---|
| FMT and Diet intervention | Experimental | Participants will receive a once daily dose (4 pills) of young donor fecal microbiome transplant (FMT) for two weeks and a microbiome rejuvenating diet (MRD) intervention for 8 weeks. The dietary intervention consists of dietitian-guided increase to ~3 servings/day fermented foods and ≥30-40 g/day or +20g fiber(plant-based whole food) and 5g of resistant starch and 5g of psyllium husk supplements over 8 weeks. Receives: Drug: Fecal Microbiota Transplant Capsules; Behavioral: Microbiome Rejuvenating Diet |
| FMT | Experimental | Participants will receive a once daily dose of young donor FMT for two weeks. Receives: Drug: Fecal Microbiota Transplant Capsules |
| Placebo FMT and diet | Active comparator | Participants receive placebo pills that are identical in shape size and feel to the active therapeutic daily for 2 weeks and will comply with a microbiome rejuvenating diet (MRD) for 8 weeks. The dietary intervention consists of dietitian-guided increase to ~3 servings/day fermented foods and ≥30-40 g/day or +20g fiber(plant-based whole food) and 5g of resistant starch and 5g of psyllium husk supplements over 8 weeks. Receives: Behavioral: Microbiome Rejuvenating Diet; Other: Placebo Fecal Microbiota Transplantation |
| Placebo FMT | Placebo comparator | Participants receive placebo pills that are identical in shape size and feel to the active therapeutic daily for 2 weeks Receives: Other: Placebo Fecal Microbiota Transplantation |
What is being measured
The primary outcome is the main question the study is designed to answer.
Difference in DunedinPACE
Difference in the 8-week change from baseline in DunedinPACE among the four randomized groups (FMT + MRD, FMT alone, MRD + placebo FMT, and placebo FMT), assessed by DNA methylation analysis of whole blood. DunedinPACE is a DNA methylation biomarker that quantifies the pace of biological aging, reported as a rate of biological aging per chronological year; higher values indicate a faster pace of aging and lower values indicate a slower pace.
Measured: Baseline and 8 weeks
Secondary outcomes (27)
Difference in Epigenetic Age
Difference in the 8-week change from baseline in epigenetic age among the four randomized groups (FMT + MRD, FMT alone, MRD + placebo FMT, and placebo FMT), assessed by epigenetic clocks (PC GrimAge, PC PhenoAge, and Horvath).
Measured: Baseline and 8 weeks
Difference in Telomere Length
Difference in the 8-week change from baseline in telomere length among the four randomized groups (FMT + MRD, FMT alone, MRD + placebo FMT, and placebo FMT), assessed by DNA methylation-based estimation.
Measured: Baseline and 8 weeks
Difference in Gut Microbial Alpha Diversity
Difference in the 8-week change from baseline in gut microbial alpha diversity among the four randomized groups (FMT + MRD, FMT alone, MRD + placebo FMT, and placebo FMT), assessed by the Shannon diversity index from shotgun metagenomic sequencing of stool.
Measured: Baseline and 8 weeks
Difference in Interleukin-6 (IL-6)
Difference in the 8-week change from baseline in Interleukin-6 (IL-6) among the four randomized groups (FMT + MRD, FMT alone, MRD + placebo FMT, and placebo FMT).
Measured: Baseline and 8 weeks
Difference in High-Sensitivity C-Reactive Protein (hsCRP)
Difference in the 8-week change from baseline in High-Sensitivity C-Reactive Protein (hsCRP) among the four randomized groups (FMT + MRD, FMT alone, MRD + placebo FMT, and placebo FMT).
Measured: Baseline and 8 weeks
Difference in Growth Differentiation Factor-15 (GDF-15)
Difference in the 8-week change from baseline in Growth Differentiation Factor-15 (GDF-15) among the four randomized groups (FMT + MRD, FMT alone, MRD + placebo FMT, and placebo FMT).
Measured: Baseline and 8 weeks
Difference in Cytokines and Inflammatory Proteins
Difference in the 8-week change from baseline in a panel of cytokines and inflammatory proteins, including CC- and CXC-motif chemokines (CCL and CXCL), among the four randomized groups (FMT + MRD, FMT alone, MRD + placebo FMT, and placebo FMT), assessed by the NUcleic acid Linked Immuno-Sandwich Assay (NULISA™) and Olink proximity extension assay.
Measured: Baseline and 8 weeks
Difference in Gut Microbiome Composition
Difference in the 8-week change from baseline in gut microbiome composition among the four randomized groups (FMT + MRD, FMT alone, MRD + placebo FMT, and placebo FMT), assessed by shotgun metagenomic sequencing of stool.
Measured: Baseline and 8 weeks
Difference in Gut Microbial Beta Diversity
Difference in the 8-week change from baseline in gut microbial beta diversity among the four randomized groups (FMT + MRD, FMT alone, MRD + placebo FMT, and placebo FMT), assessed by between-sample dissimilarity from shotgun metagenomic sequencing of stool.
Measured: Baseline and 8 weeks
Difference in Gut Microbiome Functional Capacity
Difference in the 8-week change from baseline in gut microbiome functional capacity among the four randomized groups (FMT + MRD, FMT alone, MRD + placebo FMT, and placebo FMT), assessed by functional pathway and gene content profiling from shotgun metagenomic sequencing of stool.
Measured: Baseline and 8 weeks
Engraftment of Donor-Derived Microbial Strains
Detection, relative abundance, and persistence of donor-derived microbial strains in recipient stool in the FMT-treated groups compared with the placebo FMT groups, assessed by shotgun metagenomic sequencing.
Measured: Baseline, 8 weeks, and 12 weeks
Difference in Metabolomic Profiles
Difference in the 8-week change from baseline in metabolomic profiles, including short-chain fatty acids, secondary bile acids, and aryllactates, among the four randomized groups (FMT + MRD, FMT alone, MRD + placebo FMT, and placebo FMT), assessed by targeted and untargeted metabolomics of stool and blood.
Measured: Baseline and 8 weeks
Difference in Grip Strength
Difference in the 8-week change from baseline in grip strength among the four randomized groups (FMT + MRD, FMT alone, MRD + placebo FMT, and placebo FMT), assessed by hand dynamometry and measured in kilograms. Higher values indicate greater muscle strength.
Measured: Baseline and 8 weeks
Difference in Timed Up and Go (TUG)
Difference in the 8-week change from baseline in the Timed Up and Go (TUG) test among the four randomized groups (FMT + MRD, FMT alone, MRD + placebo FMT, and placebo FMT), measured in seconds. Lower values indicate better mobility.
Measured: Baseline and 8 weeks
Difference in Cognitive Function, Mini-Mental State Examination (MMSE)
Difference in the 8-week change from baseline in cognitive function among the four randomized groups (FMT + MRD, FMT alone, MRD + placebo FMT, and placebo FMT), assessed by the Mini-Mental State Examination (MMSE). Scores range from 0 to 30; higher scores indicate better cognitive function.
Measured: Baseline and 8 weeks
Difference in Cognitive Function, Montreal Cognitive Assessment (MoCA)
Difference in the 8-week change from baseline in cognitive function among the four randomized groups (FMT + MRD, FMT alone, MRD + placebo FMT, and placebo FMT), assessed by the Montreal Cognitive Assessment (MoCA). Scores range from 0 to 30; higher scores indicate better cognitive function.
Measured: Baseline and 8 weeks
Difference in Physical Function
Difference in the 8-week change from baseline in self-reported physical function among the four randomized groups (FMT + MRD, FMT alone, MRD + placebo FMT, and placebo FMT), assessed by the Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function short form. Scores are reported as T-scores standardized to a population mean of 50 and standard deviation of 10; higher scores indicate better physical function.
Measured: Baseline and 8 weeks
Difference in Fatigue
Difference in the 8-week change from baseline in self-reported fatigue among the four randomized groups (FMT + MRD, FMT alone, MRD + placebo FMT, and placebo FMT), assessed by the Patient-Reported Outcomes Measurement Information System (PROMIS) Fatigue short form. Scores are reported as T-scores standardized to a population mean of 50 and standard deviation of 10; higher scores indicate greater fatigue.
Measured: Baseline and 8 weeks
Difference in Frailty
Difference in the 8-week change from baseline in frailty among the four randomized groups (FMT + MRD, FMT alone, MRD + placebo FMT, and placebo FMT), assessed by the FRAIL scale. Scores range from 0 to 5; higher scores indicate greater frailty.
Measured: Baseline and 8 weeks
Difference in Weight
Difference in the 8-week change from baseline in weight among the four randomized groups (FMT + MRD, FMT alone, MRD + placebo FMT, and placebo FMT), measured in kilograms.
Measured: Baseline and 8 weeks
Difference in Body Mass Index (BMI)
Difference in the 8-week change from baseline in Body Mass Index (BMI) among the four randomized groups (FMT + MRD, FMT alone, MRD + placebo FMT, and placebo FMT), measured in kilograms per square meter.
Measured: Baseline and 8 weeks
Difference in Systolic Blood Pressure
Difference in the 8-week change from baseline in systolic blood pressure among the four randomized groups (FMT + MRD, FMT alone, MRD + placebo FMT, and placebo FMT), measured in millimeters of mercury.
Measured: Baseline and 8 weeks
Difference in Diastolic Blood Pressure
Difference in the 8-week change from baseline in diastolic blood pressure among the four randomized groups (FMT + MRD, FMT alone, MRD + placebo FMT, and placebo FMT), measured in millimeters of mercury.
Measured: Baseline and 8 weeks
Difference in Dietary Fiber Intake
Difference in the 8-week change from baseline in total dietary fiber intake among the four randomized groups (FMT + MRD, FMT alone, MRD + placebo FMT, and placebo FMT), measured in grams per day and assessed by 24-hour dietary recalls using the Nutrition Data System for Research (NDSR).
Measured: Baseline and 8 weeks
Difference in Fermented Food Intake
Difference in the 8-week change from baseline in fermented food intake among the four randomized groups (FMT + MRD, FMT alone, MRD + placebo FMT, and placebo FMT), measured in servings per day and assessed by 24-hour dietary recalls using the Nutrition Data System for Research (NDSR).
Measured: Baseline and 8 weeks
Incidence of Treatment-Emergent Adverse Events
Number of participants with treatment-emergent adverse events and serious adverse events among the four randomized groups (FMT + MRD, FMT alone, MRD + placebo FMT, and placebo FMT), with severity graded by the Common Terminology Criteria for Adverse Events (CTCAE) version 5.0 and relatedness assessed by the investigator.
Measured: Informed consent through 12 weeks
Difference in Gastrointestinal and Systemic Tolerability Symptom Scores
Difference in the 8-week change from baseline in gastrointestinal and systemic tolerability symptom scores among the four randomized groups (FMT + MRD, FMT alone, MRD + placebo FMT, and placebo FMT), assessed by the weekly study tolerability questionnaire.
Measured: Baseline and 8 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted17 Sep 2026
- Study startDec 2026 (estimated)
- Primary completionJan 2028 (estimated)
- Study completionJun 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for AgingStudies of the same condition, open and under way.
- More trials run by Stanford UniversityThe 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 2
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Factorial
- Model description
- Study will consist of 4 arms Arm 1: FMT + Diet Arm 2: FMT Arm 3: Placebo + Diet Arm 4: Placebo
- Masking
- Double blind
- Who is masked
- Participant, Care provider
- Enrolment
- 80 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Stanford University
- Sponsor type
- University, hospital or other
- Collaborators
- University of Minnesota
- Responsible party
- Principal investigator, Sean Spencer, Stanford University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07826793
- Sponsor's protocol ID
- IRB-87419
- Acronym
- ENGRAFT
- Status last verified
- Sep 2026
- First submitted
- 25 Aug 2026
- Last updated
- 17 Sep 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 17 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Ecosystem Nourishment for Gut Restoration After Fecal Transplantation
- ClinicalTrials.gov ID
- NCT07826793
- Acronym / sponsor ID
- ENGRAFT / IRB-87419
- Conditions
- Aging
- Keywords
- Fecal Microbiome Transplant, Aging, Young-donor FMT, Microbiome Rejuvenating Diet, Inflammaging, Gut Microbiome, DunedinPACE
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 80 participants (estimated)
- Lead sponsor
- Stanford UniversityUniversity, hospital or other
- Collaborators
- University of Minnesota
- Study start
- Dec 2026 (estimated)
- Primary completion
- Jan 2028 (estimated)
- Study completion
- Jun 2028 (estimated)
- First posted
- 17 Sep 2026 (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 purpose of this study is to test whether young-donor fecal microbiome transplantation (FMT) and a fermented, plant-rich high-fiber, microbiome rejuvenating diet (MRD) reduce inflammatory and biological aging markers. Participants (≥40 years) will be randomized (1:1:1:1) for 8 weeks with 4-week follow-up to: (A) diet alone, (B) FMT alone, (C) diet + FMT, or (D) Placebo FMT. We will use rigorously screened young and healthy FMT donors and encapsulated delivery. Outcomes include change from baseline to end of dietary intervention (week 8) in markers of aging and inflammation. Secondary outcomes include defining microbiome engraftment/diversity/function, key metabolites, diet adherence, and quality-of-life.
Detailed description
For this study, the research participant will receive a once daily oral dose of healthy young FMT and diet modification to increase fiber and fermented food consumption. Throughout the study's duration, the participant will provide stool, blood and urine samples as well as a series of health questionnaires to track the impact of the intervention.
*PROTOCOL OVERVIEW* The study will begin with the selection of possible participants through the samples collected through the Stanford Microbiome Bank (IRB 85544), the participants identified will be contacted through the appropriate channels and asked to complete a short online questionnaire if interested in continuing with being a part of the protocol.After completing the questionnaire, those selected will be contacted via phone to schedule an in person appointment in the Clinical and Translational Research Unit (CTRU). During this appointment, the study team will obtain informed consent and one stool sample. Their initial stool sample will be sent outside Stanford for microbiome composition analysis which will determine if the participant is a good candidate for the protocol.
After enrollment in the protocol, the participants will be randomized in a 1:1:1:1 ratio to one of four study arms: Placebo, placebo + diet, FMT no diet, or FMT + diet. Those randomized to one of the FMT groups will be instructed to take a single oral dose of young FMT (4 capsules) for two weeks, and those randomized to a diet arm will have an initial appointment with the study's dietitian to establish a microbiome rejuvenating diet (MRD) starting with a one week ramp up period and continued for a total of 8 weeks. The main factors incorporated into the MRD will be ~3 servings/day fermented foods and ≥30-40 g/day or +20g fiber(plant-based whole food), 5g of resistant starch supplements and 5g of psyllium husk.
Throughout their enrollment in the protocol, the participants will provide stool samples weekly for analysis and complete general health and lifestyle questionnaires to assess protocol adherence and any changes in their health status. On weeks 0, 2, 4, 8 \& 12 participants will be asked to give a blood, urine and stool sample for further analysis and to complete a Nutrition Data System for Research (NDSR) questionnaire; stool is additionally collected at Week 6.
All patient samples will be coded and stored in Stanford facilities for further processing.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Factorial
- Masking
- Double blind (participant, care provider)
- Number of arms
- 4
- Model description
- Study will consist of 4 arms Arm 1: FMT + Diet Arm 2: FMT Arm 3: Placebo + Diet Arm 4: Placebo
| Arm | Type | Receives |
|---|---|---|
| FMT and Diet intervention | Experimental | Drug: Fecal Microbiota Transplant Capsules, Behavioral: Microbiome Rejuvenating DietParticipants will receive a once daily dose (4 pills) of young donor fecal microbiome transplant (FMT) for two weeks and a microbiome rejuvenating diet (MRD) intervention for 8 weeks. The dietary intervention consists of dietitian-guided increase to ~3 servings/day fermented foods and ≥30-40 g/day or +20g fiber(plant-based whole food) and 5g of resistant starch and 5g of psyllium husk supplements over 8 weeks. |
| FMT | Experimental | Drug: Fecal Microbiota Transplant CapsulesParticipants will receive a once daily dose of young donor FMT for two weeks. |
| Placebo FMT and diet | Active comparator | Behavioral: Microbiome Rejuvenating Diet, Other: Placebo Fecal Microbiota TransplantationParticipants receive placebo pills that are identical in shape size and feel to the active therapeutic daily for 2 weeks and will comply with a microbiome rejuvenating diet (MRD) for 8 weeks. The dietary intervention consists of dietitian-guided increase to ~3 servings/day fermented foods and ≥30-40 g/day or +20g fiber(plant-based whole food) and 5g of resistant starch and 5g of psyllium husk supplements over 8 weeks. |
| Placebo FMT | Placebo comparator | Other: Placebo Fecal Microbiota TransplantationParticipants receive placebo pills that are identical in shape size and feel to the active therapeutic daily for 2 weeks |
Who may qualify
- Ages
- 40 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (6 listed)
- Able and willing to provide written informed consent prior to completion of any study procedures.
- Age ≥40 years at the time of consent.
- In generally good health, as determined by medical history, medication review, and investigator assessment.
- Willing and able to comply with all study procedures, assessments, and study-related restrictions for the duration of participation.
- Willing to adhere to the study's lifestyle considerations for the duration of the study (maintain usual diet unless assigned to the diet arm; maintain usual physical activity; avoid non-essential systemic antibiotics; avoid probiotic/prebiotic/synbiotic supplements).
Key exclusion criteria (29 listed)
- Moderate or severe irritable bowel syndrome (IBS).
- Current or prior diagnosis of inflammatory bowel disease (IBD), including ulcerative colitis, Crohn's disease, or indeterminate colitis.
- Active gastrointestinal disease, including infectious gastroenteritis, colitis, gastritis, recurrent Clostridioides difficile infection, untreated Helicobacter pylori infection, or clinically significant malabsorption disorders (e.g., celiac disease).
- Major gastrointestinal surgery within the past 5 years (excluding cholecystectomy and appendectomy), or history of major bowel resection at any time.
- Body mass index (BMI) ≥40 kg/m².
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 |
|---|---|---|
| Fecal Microbiota Transplant CapsulesAlso: FMTEach dose (4 capsules) will be taken daily in the morning on an empty stomach. Clear liquids are allowed and regular breakfast can follow one hour later. If the dose is skipped, the missed dose should be skipped and the standard 4-capsule dose resumed the following morning; doses must not be doubled. There should be no solid food at the time of ingestion , solid food should be avoided at least 4 hours prior to ingestion of capsules, however, liquid diet is always allowed and a full glass of water should be taken after every dose ingestion. The treatment will be administered daily for 2 weeks. | Drug | FMT, FMT and Diet intervention |
| Microbiome Rejuvenating DietFiber intake: participants will be instructed to increase their fiber intake to >30/40g or +20g per day . There will be a 1 week ramp-up period in which participants will increase their intake progressively. Detailed instructions will be provided to include a variety of fiber sources (legumes, seeds, whole grains, nuts, vegetables, and fruits). Participants will also be instructed to include 5g of resistant starch supplements and 5g of psyllium husk in their diet. Fermented food intake: participants will be instructed to add at least 3 portions of fermented food into their daily diet. There will be a 1 week ramp-up period in which participants will increase their intake progressively and maintain a high level of consumption for the following 8 weeks. Detailed instructions will be provided to include a variety of fermented foods (fermented dairy products, fermented vegetables, fermented non-alcoholic drinks, etc.). | Behavioural | FMT and Diet intervention, Placebo FMT and diet |
| Placebo Fecal Microbiota TransplantationParticipants will receive a once daily dose (4 pills) of inactive pills that are identical in size, shape, color, taste and feel to the active FMT pills | Other | Placebo FMT, Placebo FMT and diet |
Primary outcome
Difference in DunedinPACE
Time frame: Baseline and 8 weeks
Difference in the 8-week change from baseline in DunedinPACE among the four randomized groups (FMT + MRD, FMT alone, MRD + placebo FMT, and placebo FMT), assessed by DNA methylation analysis of whole blood. DunedinPACE is a DNA methylation biomarker that quantifies the pace of biological aging, reported as a rate of biological aging per chronological year; higher values indicate a faster pace of aging and lower values indicate a slower pace.
27 secondary outcomes
Difference in Epigenetic Age
Time frame: Baseline and 8 weeks
Difference in Telomere Length
Time frame: Baseline and 8 weeks
Difference in Gut Microbial Alpha Diversity
Time frame: Baseline and 8 weeks
Difference in Interleukin-6 (IL-6)
Time frame: Baseline and 8 weeks
Difference in High-Sensitivity C-Reactive Protein (hsCRP)
Time frame: Baseline and 8 weeks
Difference in Growth Differentiation Factor-15 (GDF-15)
Time frame: Baseline and 8 weeks
Difference in Cytokines and Inflammatory Proteins
Time frame: Baseline and 8 weeks
Difference in Gut Microbiome Composition
Time frame: Baseline and 8 weeks
Difference in Gut Microbial Beta Diversity
Time frame: Baseline and 8 weeks
Difference in Gut Microbiome Functional Capacity
Time frame: Baseline and 8 weeks
Engraftment of Donor-Derived Microbial Strains
Time frame: Baseline, 8 weeks, and 12 weeks
Difference in Metabolomic Profiles
Time frame: Baseline and 8 weeks
Difference in Grip Strength
Time frame: Baseline and 8 weeks
Difference in Timed Up and Go (TUG)
Time frame: Baseline and 8 weeks
Difference in Cognitive Function, Mini-Mental State Examination (MMSE)
Time frame: Baseline and 8 weeks
Difference in Cognitive Function, Montreal Cognitive Assessment (MoCA)
Time frame: Baseline and 8 weeks
Difference in Physical Function
Time frame: Baseline and 8 weeks
Difference in Fatigue
Time frame: Baseline and 8 weeks
Difference in Frailty
Time frame: Baseline and 8 weeks
Difference in Weight
Time frame: Baseline and 8 weeks
Difference in Body Mass Index (BMI)
Time frame: Baseline and 8 weeks
Difference in Systolic Blood Pressure
Time frame: Baseline and 8 weeks
Difference in Diastolic Blood Pressure
Time frame: Baseline and 8 weeks
Difference in Dietary Fiber Intake
Time frame: Baseline and 8 weeks
Difference in Fermented Food Intake
Time frame: Baseline and 8 weeks
Incidence of Treatment-Emergent Adverse Events
Time frame: Informed consent through 12 weeks
Difference in Gastrointestinal and Systemic Tolerability Symptom Scores
Time frame: Baseline and 8 weeks
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 17 Sep 2026.
- Individual participant dataSharing planned: No
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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.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing Fecal Microbiota Transplant Capsules and Microbiome Rejuvenating Diet in people with Aging, run by Stanford University 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 29 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: opening soon, as of the sponsor's last update on 17 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. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
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 Sean P Spencer, MD PhD (650-736-6555, seanspen@stanford.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Difference in DunedinPACE (time frame: Baseline and 8 weeks). 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 17 Sep 2026.