An interventional study of Truvaga Plus in Irritable Bowel Syndrome (IBS), sponsored by University of California, Los Angeles. Not yet recruiting at 1 site in United States. Open to participants aged 18 Years to 50 Years. Per ClinicalTrials.gov, last updated 2026-11-09.
Sponsored by University of California, Los Angeles · Not applicable, Interventional, and Treatment
Irritable bowel syndrome (IBS) is a chronic disorder of gut-brain interaction that causes abdominal pain and altered bowel habits. Many people with IBS also experience symptoms outside the bowel, such as headaches, widespread pain, poor sleep, anxiety, and depression; these symptoms are especially common in females. This study focuses on stress reactivity (SR), a persistent pattern of stress-system activity that may be linked to autonomic nervous system function, immune activity, the gut microbiome, and brain processing. The investigators will enroll adults with at least moderate IBS symptoms and randomly assign them to 8 weeks of non-invasive vagal nerve stimulation (nVNS) or Usual Care. Participants assigned to nVNS will use a handheld device on the left side of the neck at home twice daily. The investigators will compare changes in IBS severity and other physical symptoms and examine whether baseline or treatment-related changes in blood, stool, heart-rate variability, sex hormones, and brain imaging measures are associated with response. The study will also explore whether treatment effects and predictors differ by sex.
1,116 studies on the registry are indexed under Irritable Bowel Syndrome; 208 are open to participants now.
This study's planned enrollment of 200 is above the median of 70 across 896 interventional studies indexed under Irritable Bowel Syndrome.
Browse Irritable Bowel Syndrome studies →University of California, Los Angeles is the lead sponsor of 1,170 studies on the registry; 195 are open to participants now.
Of its 95 completed or terminated interventional studies of FDA-regulated products, 70 (74%) have results posted.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Periods have stopped for good: usually no period for 12 months in a row without another medical reason, sometimes confirmed by a blood test (FSH).
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Postmenopausal
Periods have stopped for good: usually no period for 12 months in a row without another medical reason, sometimes confirmed by a blood test (FSH).
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Device: Participants will self-administer a transcutaneous cervical nVNS device, Truvaga Plus, which is identical to GammaCore but is rechargeable. Truvaga Plus is classified as a general wellness product that does not require FDA clearance and can be purchased without a prescription (electroCore LLC, Basking Ridge, NJ, USA, letter of support). Usage: The nVNS will be delivered via two stainless steel contact surfaces that are coated with conductive gel before each treatment. The device will be positioned in parallel with the carotid pulse on the left side of the neck. Two back-to-back 2-minute nVNS stimulations (4 minutes total) will be administered twice daily at home for 8 weeks. Intensity: Level is dependent on the patient. They will be instructed to increase the intensity until they feel a strong but comfortable sensation-tingling or a slight lip pull is common. Most users find the ideal intensity between levels 4 and Frequency: 2 sessions, 2x daily; 224 sessions total
Device: Truvaga Plus
Participants assigned to the Usual Care arm will undergo the same assessments as those in the nVNS arm but will not receive any specific intervention from the project. No restrictions will be placed on participants, except that they will be asked not to start any new therapies for IBS or any new medicines unless deemed necessary by their healthcare provider.
Self-administered transcutaneous cervical nVNS device
Change in IBS Severity Scoring System (IBS-SSS)
The IBS-SSS questionnaire is a validated measure of IBS symptom severity and has been shown to be responsive to treatment. The IBS-SSS assesses the severity of abdominal pain, frequency of abdominal pain, severity of abdominal distention, dissatisfaction with bowel habits, and interference of IBS with daily life over a 10-day period. Each of the five categories will receive a score from 0-100, and the total IBSSSS is calculated by taking the sum of these categories (range 0-500, 0 - no symptoms, 500 - very severe symptoms).
Time frame: 8 weeks, from baseline to end of intervention
Change in Patient Health Questionnaire-15 (PHQ-15)
The PHQ-15 is a widely used measure of widespread somatic symptoms over 1 month that is sensitive to treatment effects. The PHQ-15 assess 15 different somatic symptoms (back pain, stomach pain, headaches, chest pain, trouble sleeping, etc.) rated by 0 - not bothered at all to 3 - bothered a lot. The scale is scored as follows: 0-4: Minimal somatic symptom severity, 5-9: Low somatic symptom severity, 10-14: Medium somatic symptom severity, 15-30: High somatic symptom severity.
Time frame: 8 weeks, from baseline to end of intervention
Change in stress reactivity (SR)-related brain phenotypes.
SR-related brain phenotypes will be derived from prespecified MRI measures of brain structure, functional connectivity, and brain activity. MRI data will be collected at baseline and Week 8. The primary imaging analysis will compare baseline-to-Week-8 change in prespecified SR-related brain phenotypes between nVNS and Usual Care.
Time frame: 8 weeks, from baseline to end of intervention
IBS Severity Scoring System (IBS-SSS) responder rate
The proportion of participants with IBS who experience a ≥50-point reduction in IBS-SSS score from baseline will be compared between treatment groups. A reduction of at least 50 points represents a clinically meaningful improvement in IBS symptoms. The IBS-SSS questionnaire is a validated measure of IBS symptom severity and has been shown to be responsive to treatment. The IBS-SSS assesses the severity of abdominal pain, frequency of abdominal pain, severity of abdominal distention, dissatisfaction with bowel habits, and interference of IBS with daily life over a 10-day period. Each of the five categories will receive a score from 0-100, and the total IBSSSS is calculated by taking the sum of these categories (range 0-500, 0 - no symptoms, 500 - very severe symptoms).
Time frame: 8 weeks, from baseline to end of intervention
Biologic measures of Stress Reactivity - SNS-Immune gene expression profile
Changes in the sympathetic nervous system (SNS)-immune gene expression profile will be evaluated as a peripheral biologic measure of stress reactivity. Whole-blood SNS-immune gene expression will be measured using mRNA-targeted sequencing. Total RNA will be isolated from whole blood, converted to cDNA using Lexogen QuantSeq 3' FWD, sequenced using Illumina sequencing, mapped to the GRCh38 reference human transcriptome using STAR, and quantified as gene-specific reads per million mapped reads. Baseline-to-Week-8 changes will be compared between nVNS and Usual Care and examined in relation to clinical symptom change. Moderator analyses will also test whether baseline SNS-immune gene expression modifies the treatment response using an SNS-immune measure-by-treatment-by-time interaction.
Time frame: 8 weeks, from baseline to end of intervention
Biologic measures of Stress Reactivity - heart rate variability (HRV)
HRV will be evaluated as a peripheral autonomic measure of stress reactivity and compared over the treatment period. HRV will be derived from physiologic data collected using a Fitbit equipped with photoplethysmography sensors that estimate heart rate and intervals between successive beats. Participants will wear the device from baseline through the post-intervention assessment, including during sleep, to characterize longitudinal and circadian HRV. Changes in HRV will be compared between nVNS and Usual Care and correlated with symptom change. Moderator analyses will additionally test whether baseline HRV modifies treatment response through an HRV-by-treatment-by-time interaction.
Time frame: 8 weeks, from baseline to end of intervention
Biologic measures of Stress Reactivity - fecal microbial stress index
Changes in the fecal microbial stress index will be evaluated as a peripheral biologic measure of stress reactivity. The fecal microbial stress index will be derived from stool samples collected at baseline and Week 8 using shotgun metagenomic sequencing. Microbial sequencing data will undergo species-level taxonomic and functional characterization. Baseline-to-Week-8 changes in the microbial stress index will be compared between nVNS and Usual Care and correlated with clinical symptom change.
Time frame: 8 weeks, from baseline to end of intervention
Biologic measures of Stress Reactivity - fecal metabolite stress index
Changes in the fecal metabolite stress index will be evaluated as a peripheral biologic measure of stress reactivity. The fecal metabolite stress index will be derived from stool metabolomic data obtained using LC-MS/MS-based profiling. Baseline-to-Week-8 changes in the metabolite stress index will be compared between nVNS and Usual Care and correlated with clinical symptom change. Moderator analyses will additionally test whether the baseline metabolite stress index modifies treatment response through a metabolite stress index-by-treatment-by-time interaction.
Time frame: 8 weeks, from baseline to end of intervention
Brain changes associated with IBS severity, comorbid symptom scores, and peripheral biologic measures of SR
Examine associations between changes in scores on the SR-related brain phenotype signatures and changes in IBS severity, comorbid symptom scores, and peripheral biologic measures of SR. General linear models will examine associations between baseline-to-Week-8 changes in SR-related brain phenotype signature scores and corresponding changes in IBS-SSS, PHQ-15, HRV, SNS-immune gene expression, and microbial and metabolite stress indices, with adjustment for relevant covariates. Alternative approaches may be used to examine multivariate associations between changes in symptom severity, stress reactivity, comorbidity, and brain connectivity.
Time frame: 8 weeks, from baseline to end of intervention
Change in extraintestinal symptoms in nVNS compared to Usual Care
Predict response (Pre-Post change in extraintestinal symptoms) in nVNS compared to Usual Care. General linear model-based moderator analyses will evaluate whether baseline SR-related brain phenotype scores predict pre- to post-treatment change in extraintestinal symptom severity differently in participants assigned to nVNS versus Usual Care. Models will include baseline SR brain phenotype score, treatment group, the brain phenotype-by-treatment interaction, and prespecified covariates. A significant interaction will indicate differential prediction of treatment response.
Time frame: 8 weeks, from baseline to end of intervention
Exploratory outcome - Sex differences
Examine whether females with IBS with higher comorbid symptom scores will present with greater changes in SR-related brain signatures following the nVNS intervention compared to male IBS. Exploratory models will examine whether females with IBS with greater baseline comorbid symptom burden demonstrate greater baseline-to-Week-8 changes in SR-related brain signatures following nVNS compared with males with IBS. The moderator analysis includes the comorbid symptom score-by-group interaction, with adjustment for age, BMI, and diet.
Time frame: 8 weeks, from baseline to end of intervention
PDFs hosted by the registry, ClinicalTrials.gov.
Plan to share: No — No plans to share individual participant data.
Start is estimated for Dec 2026; primary completion for Dec 2031, 60 months later.
Of 305 non-industry interventional studies with no phase under Irritable Bowel Syndrome, half reached primary completion within 21 months of starting (the median), counting those still running; a quarter within 9 and three quarters within 40. This study's planned 60 months is above that.
Counting every sponsor, half of 357 studies reached it within 19 months; a quarter within 9 and three quarters within 38.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is not yet recruiting, as verified in Nov 2026. You cannot join it, but the record below documents what was studied.
Get an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
University of California, Los Angeles →