Healthy AdultNCT07700368
Effect of Monosodium Glutamate on Microbiome-Derived Imidazole Propionate Production in Healthy Volunteers
A study testing L-histidine, Monosodium glutamate (MSG) and Sodium chloride (NaCl) in people with Healthy Adult, run by University of Chicago at 1 site in United States.
Trial summary
The goal of this clinical trial is to learn whether dietary monosodium glutamate (MSG), a common food flavor enhancer, increases the blood level of a gut-microbiome-derived compound called imidazole propionate (ImP) in healthy adult volunteers. Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- Conditions the study is for
- Healthy Adult
- What is being tested?
- L-histidine, Monosodium glutamate (MSG) and Sodium chloride (NaCl)
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 18 participants
- Where
- 1 siteUnited States
- Study dates
- 15 Jul 2026to 31 Dec 2027
- 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 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Age 18 years or older
- No antibiotic use in the previous 3 months
Who cannot join
- Diagnosis of diabetes or prediabetes (any type)
- Inflammatory bowel disease or other gastrointestinal disorder
- Known allergy or intolerance to monosodium glutamate (MSG)
- Pregnancy or breastfeeding
- Current participation in another clinical trial
- High habitual dietary intake of MSG or histidine
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
Duchossois Family Institute, Knapp Center for Biomedical Discovery (KCBD), Room 4214
Chicago, Illinois, 60637
Sam Light, 773-702-3435, samlight@uchicago.edu
About this study
The goal of this clinical trial is to learn whether dietary monosodium glutamate (MSG), a common food flavor enhancer, increases the blood level of a gut-microbiome-derived compound called imidazole propionate (ImP) in healthy adult volunteers. ImP is a compound made by gut bacteria from the amino acid histidine, and higher blood levels have been linked to problems with blood-sugar control. The main questions this trial aims to answer are:
Does taking MSG together with L-histidine increase blood ImP levels compared with taking a salt (sodium chloride) placebo together with L-histidine? How do blood ImP levels change over time in response to MSG and L-histidine taken together?
Read more
Researchers will compare a 7-day period of L-histidine plus MSG against a 7-day period of L-histidine plus sodium chloride (a salt placebo with matching sodium content) to see whether MSG changes blood ImP levels. Each participant completes both periods in random order and serves as their own comparison.
Participants will:
Take L-histidine capsules twice daily (morning and evening with meals) during two separate 7-day periods.
Dissolve either MSG powder or salt powder in water and drink it twice daily during each period, with the two periods separated by a 7-day break (washout).
Give a fasting blood sample at the start of the study and on day 7 of each period.
Optionally provide a stool sample at the end of each period. Complete a daily treatment diary and a follow-up phone call after the final sample.
- Conditions
- Healthy Adult
- Being tested
- L-histidine, Monosodium glutamate (MSG), Sodium chloride (NaCl)
- Keywords
- Monosodium glutamate
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
L-histidineDietary supplement
USP-grade L-histidine, 4 g/day, taken as capsules divided into 2 g in the morning and 2 g in the evening with meals, during each 7-day treatment period. Administered in both treatment periods for all participants.
Monosodium glutamate (MSG)Dietary supplement
Food-grade monosodium glutamate, 3 g/day, provided as identical-appearing single-dose powder sachets divided into 1.5 g in the morning and 1.5 g in the evening, each dissolved in approximately 240 mL
Sodium chloride (NaCl)Dietary supplement
USP-grade sodium chloride, 940 mg/day, provided as identical-appearing single-dose powder sachets divided into 470 mg in the morning and 470 mg in the evening, each dissolved in approximately 240 mL of water and taken with meals during the placebo treatment period. The sodium content is matched to that of the 3 g/day MSG dose to isolate the effect of glutamate.
| Study group | Role | What they receive |
|---|---|---|
| Sequence 1: L-histidine + MSG, then L-histidine + NaCl | Experimental | Participants receive L-histidine (4 g/day) plus monosodium glutamate (MSG; 3 g/day) during the first 7-day treatment period, followed by a 7-day washout, then L-histidine (4 g/day) plus sodium chloride (NaCl; 940 mg/day) during the second 7-day treatment period. L-histidine is taken as capsules (2 g morning, 2 g evening with meals); MSG and NaCl are dissolved in approximately 240 mL of water and taken twice daily (morning and evening with meals). Receives: Dietary Supplement: L-histidine; Dietary Supplement: Monosodium glutamate (MSG); Dietary Supplement: Sodium chloride (NaCl) |
| Sequence 2: L-histidine + NaCl, then L-histidine + MSG | Experimental | Participants receive L-histidine (4 g/day) plus sodium chloride (NaCl; 940 mg/day) during the first 7-day treatment period, followed by a 7-day washout, then L-histidine (4 g/day) plus monosodium glutamate (MSG; 3 g/day) during the second 7-day treatment period. L-histidine is taken as capsules (2 g morning, 2 g evening with meals); MSG and NaCl are dissolved in approximately 240 mL of water and taken twice daily (morning and evening with meals). Receives: Dietary Supplement: L-histidine; Dietary Supplement: Monosodium glutamate (MSG); Dietary Supplement: Sodium chloride (NaCl) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Difference in blood imidazole propionate concentration between the monosodium glutamate and sodium chloride treatment periods
Blood imidazole propionate concentration measured by liquid chromatography-mass spectrometry (LC-MS) from the blood sample collected on day 7 of each 7-day treatment period. The outcome is the within-participant difference between the day-7 concentration following the L-histidine + MSG period and the day-7 concentration following the L-histidine + NaCl period.
Measured: Day 7 of each treatment period
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted14 Jul 2026
- Study start15 Jul 2026 (estimated)
- Primary completion31 Dec 2027 (estimated)
- Study completion31 Dec 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Healthy AdultStudies of the same condition, open and under way.
- More trials run by University of ChicagoThe 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
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 18 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of Chicago
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07700368
- Sponsor's protocol ID
- IRB25-1212
- Status last verified
- Jul 2026
- First submitted
- 8 Jul 2026
- Last updated
- 14 Jul 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes
Study at a glance
From the registry record, last updated by the sponsor on 14 Jul 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effect of Monosodium Glutamate on Microbiome-Derived Imidazole Propionate Production in Healthy Volunteers
- ClinicalTrials.gov ID
- NCT07700368
- Acronym / sponsor ID
- IRB25-1212
- Conditions
- Healthy Adult
- Keywords
- Monosodium glutamate
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 18 participants (estimated)
- Lead sponsor
- University of ChicagoUniversity, hospital or other
- Study start
- 15 Jul 2026 (estimated)
- Primary completion
- 31 Dec 2027 (estimated)
- Study completion
- 31 Dec 2027 (estimated)
- First posted
- 14 Jul 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 goal of this clinical trial is to learn whether dietary monosodium glutamate (MSG), a common food flavor enhancer, increases the blood level of a gut-microbiome-derived compound called imidazole propionate (ImP) in healthy adult volunteers. ImP is a compound made by gut bacteria from the amino acid histidine, and higher blood levels have been linked to problems with blood-sugar control. The main questions this trial aims to answer are:
Does taking MSG together with L-histidine increase blood ImP levels compared with taking a salt (sodium chloride) placebo together with L-histidine? How do blood ImP levels change over time in response to MSG and L-histidine taken together?
Researchers will compare a 7-day period of L-histidine plus MSG against a 7-day period of L-histidine plus sodium chloride (a salt placebo with matching sodium content) to see whether MSG changes blood ImP levels. Each participant completes both periods in random order and serves as their own comparison.
Participants will:
Take L-histidine capsules twice daily (morning and evening with meals) during two separate 7-day periods.
Dissolve either MSG powder or salt powder in water and drink it twice daily during each period, with the two periods separated by a 7-day break (washout).
Give a fasting blood sample at the start of the study and on day 7 of each period.
Optionally provide a stool sample at the end of each period. Complete a daily treatment diary and a follow-up phone call after the final sample.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind (participant, investigator)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Sequence 1: L-histidine + MSG, then L-histidine + NaCl | Experimental | Dietary Supplement: L-histidine, Dietary Supplement: Monosodium glutamate (MSG), Dietary Supplement: Sodium chloride (NaCl)Participants receive L-histidine (4 g/day) plus monosodium glutamate (MSG; 3 g/day) during the first 7-day treatment period, followed by a 7-day washout, then L-histidine (4 g/day) plus sodium chloride (NaCl; 940 mg/day) during the second 7-day treatment period. L-histidine is taken as capsules (2 g morning, 2 g evening with meals); MSG and NaCl are dissolved in approximately 240 mL of water and taken twice daily (morning and evening with meals). |
| Sequence 2: L-histidine + NaCl, then L-histidine + MSG | Experimental | Dietary Supplement: L-histidine, Dietary Supplement: Monosodium glutamate (MSG), Dietary Supplement: Sodium chloride (NaCl)Participants receive L-histidine (4 g/day) plus sodium chloride (NaCl; 940 mg/day) during the first 7-day treatment period, followed by a 7-day washout, then L-histidine (4 g/day) plus monosodium glutamate (MSG; 3 g/day) during the second 7-day treatment period. L-histidine is taken as capsules (2 g morning, 2 g evening with meals); MSG and NaCl are dissolved in approximately 240 mL of water and taken twice daily (morning and evening with meals). |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (2 listed)
- Age 18 years or older
- No antibiotic use in the previous 3 months
Key exclusion criteria (6 listed)
- Diagnosis of diabetes or prediabetes (any type)
- Inflammatory bowel disease or other gastrointestinal disorder
- Known allergy or intolerance to monosodium glutamate (MSG)
- Pregnancy or breastfeeding
- Current participation in another clinical trial
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-histidineUSP-grade L-histidine, 4 g/day, taken as capsules divided into 2 g in the morning and 2 g in the evening with meals, during each 7-day treatment period. Administered in both treatment periods for all participants. | Dietary supplement | Sequence 1: L-histidine + MSG, then L-histidine + NaCl, Sequence 2: L-histidine + NaCl, then L-histidine + MSG |
| Monosodium glutamate (MSG)Food-grade monosodium glutamate, 3 g/day, provided as identical-appearing single-dose powder sachets divided into 1.5 g in the morning and 1.5 g in the evening, each dissolved in approximately 240 mL | Dietary supplement | Sequence 1: L-histidine + MSG, then L-histidine + NaCl, Sequence 2: L-histidine + NaCl, then L-histidine + MSG |
| Sodium chloride (NaCl)USP-grade sodium chloride, 940 mg/day, provided as identical-appearing single-dose powder sachets divided into 470 mg in the morning and 470 mg in the evening, each dissolved in approximately 240 mL of water and taken with meals during the placebo treatment period. The sodium content is matched to that of the 3 g/day MSG dose to isolate the effect of glutamate. | Dietary supplement | Sequence 1: L-histidine + MSG, then L-histidine + NaCl, Sequence 2: L-histidine + NaCl, then L-histidine + MSG |
Primary outcome
Difference in blood imidazole propionate concentration between the monosodium glutamate and sodium chloride treatment periods
Time frame: Day 7 of each treatment period
Blood imidazole propionate concentration measured by liquid chromatography-mass spectrometry (LC-MS) from the blood sample collected on day 7 of each 7-day treatment period. The outcome is the within-participant difference between the day-7 concentration following the L-histidine + MSG period and the day-7 concentration following the L-histidine + NaCl period.
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 14 Jul 2026.
- Individual participant dataSharing planned: Yes
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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 study testing L-histidine, Monosodium glutamate (MSG) and Sodium chloride (NaCl) in people with Healthy Adult, run by University of Chicago 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 2 inclusion and 6 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 14 Jul 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 Sam Light, PhD (773-702-3435, samlight@uchicago.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Difference in blood imidazole propionate concentration between the monosodium glutamate and sodium chloride treatment periods (time frame: Day 7 of each treatment period). 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 14 Jul 2026.