Gut Dysbiosis for TMAO Production From L-carnitine ConsumptionNCT05980884
Using Gut Microbial Gbu Gene Testing to Estimate Host TMAO Production Capacity
A study testing L-carnitine in people with Gut Dysbiosis for TMAO Production From L-carnitine Consumption, run by National Taiwan University Hospital at 1 site in Taiwan.
Trial summary
The risk of cardiovascular diseases from red meat consumption varies among individuals due to variations in gut microbiota. L-carnitine in red meat can be converted to TMAO in the body by certain bacteria. Not everyone experiences a significant increase in TMAO levels after consuming carnitine. Read more about this study
- Who is it for?
- Ages 18 to 70 yearsHealthy volunteers can take part
- Conditions the study is for
- Gut Dysbiosis for TMAO Production From L-carnitine Consumption
- What is being tested?
- L-carnitine
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 230 participants
- Where
- 1 siteTaiwan
- Study dates
- 24 Jul 2023to 30 Jul 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 70 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Adult with age between 18 to 70
- Must be able to swallow tablets
Who cannot join
- Antibiotics use within one month
- L-carnitine supplement use within one month
- Chronic diarrhea
- Myasthenia gravis
- Diabetes mellitus
- Parathyroid disorders
Show all 10Show fewer
- Chronic kidney disease
- Epilepsy
- Severe anemia
- Cardiovascular diseases.
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Evaluation of Microbial-derived TMAO Production From Carnitine Intake by Testing Fecal Gbu Gene
The risk of cardiovascular diseases from red meat consumption varies among individuals due to variations in gut microbiota. L-carnitine in red meat can be converted to TMAO in the body by certain bacteria. Not everyone experiences a significant increase in TMAO levels after consuming carnitine. Gut microbiota differences are observed between high and low TMAO producers. The presence of the gbu gene in gut microbiota is linked to TMAO production. This clinical research aims to determine if the gbu gene can predict TMAO levels after dietary carnitine intake.
Read the detailed description
The risk of developing cardiovascular diseases due to the consumption of red meat varies among individuals, and this may be attributed to differences in the composition and function of gut microbiota. Studies have found that red meat, rich in L-carnitine, may be metabolized by certain anaerobic bacteria in the intestines to produce trimethylamine N-oxide (TMAO) in the human body. Previous research utilizing the oral carnitine challenge test (OCCT) revealed that not everyone experiences a significant increase in blood TMAO levels after consuming carnitine. Moreover, individuals with high TMAO production and low TMAO production showed distinct differences in their gut microbiota.
Furthermore, we have discovered a significant correlation between the abundance of the gbu gene in gut microbiota and the production of TMAO in response to dietary carnitine intake. Therefore, through the design of clinical research, we aim to investigate and assess whether the abundance of the gbu gene in gut microbiota can predict the levels of TMAO produced in the human body under dietary carnitine intake.
- Being tested
- L-carnitine
- Keywords
- gbu gene cluster, TMAO, gut microbiota, red meat, cardiovascular disease
- Medical subject headings
- Cardiovascular Diseases
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
L-carnitineDietary supplement
Participants are required to take a capsule containing 500mg L-carnitine/day continuous for 7-10 days.
| Study group | Role | What they receive |
|---|---|---|
| L-Carnitine supplementation | Experimental | Participants are required to take a capsule containing 500mg L-carnitine/day continuous for 7-10 days. During the intervention, participants are asked to collect urine sample and dietary record each day. Blood and fecal samples will be collected before and after the intervention. Each participant needs to complete a food frequency questionnaire. Receives: Dietary Supplement: L-carnitine |
What is being measured
The primary outcome is the main question the study is designed to answer.
Blood TMAO level measured by LC-MS/MS
Measured: up to 7-10 days
Urine TMAO level measured by LC-MS/MS
Measured: up to 7-10 days
Fecal gbuB gene abundance measured by qPCR
Measured: up to 7-10 days
Secondary outcomes (2)
Carnitine intake measured by 24hr dietary record
Measured: up to 7-10 days
Gut microbiome profiles measured by shotgun metagenome sequencing
Measured: up to 7-10 days
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted8 Aug 2023
- Study start24 Jul 2023
- Primary completion25 Apr 2026 (estimated)
- Study completion30 Jul 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Gut Dysbiosis for TMAO Production From L-carnitine ConsumptionStudies of the same condition, open and under way.
- More trials run by National Taiwan University HospitalThe 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
- 230 participants (estimated)
Sponsor and investigators
- Lead sponsor
- National Taiwan University Hospital
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05980884
- Sponsor's protocol ID
- 202303144RINA
- Status last verified
- Jan 2026
- First submitted
- 20 Jul 2023
- Last updated
- 12 Jan 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: The data will be uploaded to be public when the research is published
Publications
Wu WK, Lo YL, Chiu JY, Hsu CL, Lo IH, Panyod S, Liao YC, Chiu THT, Yang YT, Kuo HC, Zou HB, Chen YH, Chuang HL, Yen JJY, Wang JT, Chiu HM, Hsu CC, Kuo CH, Sheen LY, Kao HL, Wu MS. Gut microbes with the gbu genes determine TMAO production from L-carnitine intake and serve as a biomarker for precision nutrition. Gut Microbes. 2025 Dec;17(1):2446374. doi: 10.1080/19490976.2024.2446374. Epub 2024 Dec 26.
PubMed 39722590
Study at a glance
From the registry record, last updated by the sponsor on 12 Jan 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Evaluation of Microbial-derived TMAO Production From Carnitine Intake by Testing Fecal Gbu Gene
- ClinicalTrials.gov ID
- NCT05980884
- Acronym / sponsor ID
- 202303144RINA
- Keywords
- gbu gene cluster, TMAO, gut microbiota, red meat, cardiovascular disease
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 230 participants (estimated)
- Lead sponsor
- National Taiwan University HospitalUniversity, hospital or other
- Study start
- 24 Jul 2023 (actual)
- Primary completion
- 25 Apr 2026 (estimated)
- Study completion
- 30 Jul 2026 (estimated)
- First posted
- 8 Aug 2023 (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 risk of cardiovascular diseases from red meat consumption varies among individuals due to variations in gut microbiota. L-carnitine in red meat can be converted to TMAO in the body by certain bacteria. Not everyone experiences a significant increase in TMAO levels after consuming carnitine. Gut microbiota differences are observed between high and low TMAO producers. The presence of the gbu gene in gut microbiota is linked to TMAO production. This clinical research aims to determine if the gbu gene can predict TMAO levels after dietary carnitine intake.
Detailed description
The risk of developing cardiovascular diseases due to the consumption of red meat varies among individuals, and this may be attributed to differences in the composition and function of gut microbiota. Studies have found that red meat, rich in L-carnitine, may be metabolized by certain anaerobic bacteria in the intestines to produce trimethylamine N-oxide (TMAO) in the human body. Previous research utilizing the oral carnitine challenge test (OCCT) revealed that not everyone experiences a significant increase in blood TMAO levels after consuming carnitine. Moreover, individuals with high TMAO production and low TMAO production showed distinct differences in their gut microbiota.
Furthermore, we have discovered a significant correlation between the abundance of the gbu gene in gut microbiota and the production of TMAO in response to dietary carnitine intake. Therefore, through the design of clinical research, we aim to investigate and assess whether the abundance of the gbu gene in gut microbiota can predict the levels of TMAO produced in the human body under dietary carnitine intake.
Study design
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| L-Carnitine supplementation | Experimental | Dietary Supplement: L-carnitineParticipants are required to take a capsule containing 500mg L-carnitine/day continuous for 7-10 days. During the intervention, participants are asked to collect urine sample and dietary record each day. Blood and fecal samples will be collected before and after the intervention. Each participant needs to complete a food frequency questionnaire. |
Who may qualify
- Ages
- 18 to 70 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (2 listed)
- Adult with age between 18 to 70
- Must be able to swallow tablets
Key exclusion criteria (10 listed)
- Antibiotics use within one month
- L-carnitine supplement use within one month
- Chronic diarrhea
- Myasthenia gravis
- Diabetes mellitus
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 |
|---|---|---|
| L-carnitineParticipants are required to take a capsule containing 500mg L-carnitine/day continuous for 7-10 days. | Dietary supplement | L-Carnitine supplementation |
Primary outcome
Blood TMAO level measured by LC-MS/MS
Time frame: up to 7-10 days
Urine TMAO level measured by LC-MS/MS
Time frame: up to 7-10 days
Fecal gbuB gene abundance measured by qPCR
Time frame: up to 7-10 days
2 secondary outcomes
Carnitine intake measured by 24hr dietary record
Time frame: up to 7-10 days
Gut microbiome profiles measured by shotgun metagenome sequencing
Time frame: up to 7-10 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 12 Jan 2026.
- Results publication: PubMed 39722590Wu WK, Lo YL, Chiu JY, Hsu CL, Lo IH, Panyod S, Liao YC, Chiu THT, Yang YT, Kuo HC, Zou HB, Chen YH, Chuang HL, Yen JJY, Wang JT, Chiu HM, Hsu CC, Kuo CH, Sheen LY, Kao HL, Wu MS. Gut microbes with the gbu genes determine TMAO production from L-carnitine intake and serve as a biomarker for precision nutrition. Gut Microbes. 2025 Dec;17(1):2446374. doi: 10.1080/19490976.2024.2446374. Epub 2024 Dec 26.
- Individual participant dataSharing planned: No. The data will be uploaded to be public when the research is published
Related trials for Gut Dysbiosis for TMAO Production From L-carnitine Consumption
Not yet recruiting
Development of Microbial Metabolism Gene Tests for Facilitating Precision Health and Preventive Medicine-Evaluation of TMAO Production in Human Body From High-carnitine Diet by Fecal Gbu Gene Testing
Gut Dysbiosis for TMAO Production From Red Meat Consumption
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. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing L-carnitine in people with Gut Dysbiosis for TMAO Production From L-carnitine Consumption, run by National Taiwan University Hospital at 1 site in Taiwan.
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 2 inclusion and 10 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: under way, not looking for participants, as of the sponsor's last update on 12 Jan 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 Taiwan. 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?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Blood TMAO level measured by LC-MS/MS (time frame: up to 7-10 days). The study lists 3 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT05980884, which also lists 1 linked publication.
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 12 Jan 2026.