Probiotic Study in Alcohol Recovery

March 27, 2026 updated by: Kim-Marie Gehrke, Loughborough University

Effects of Probiotic Supplementation in Alcohol Use Disorder: A Randomised, Placebo-Controlled Pilot Trial

Alcohol Use Disorder (AUD) is a common condition that can affect physical and mental health. Current treatments do not work for everyone, and new approaches are needed.

This study is investigating whether taking a probiotic supplement (a type of "good bacteria") can help reduce alcohol craving and improve psychological, biological, and cognitive wellbeing.

Participants are randomly assigned to receive either a probiotic supplement or a placebo (a capsule with no active ingredients) for four weeks. Neither the participants nor the researchers know which treatment is given during the study.

The study measures alcohol craving, gastrointestinal composition, thinking and memory, mental health, and eating and drinking behaviour at the start and end of the study.

The aim is to understand whether probiotics could be a helpful additional approach to support people with AUD.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Active, not recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
38

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • A self-reported history of heavy drinking
  • At least one heavy drinking episode (≥8 units) in the last 28 days

Exclusion Criteria:

  • Participants being under 18 years of age
  • Supplementation of probiotics or prebiotics within the past 4 weeks
  • Antibiotic use within the past 4 weeks
  • Major psychiatric conditions diagnosed e.g., bipolar disorder, schizophrenia
  • Current pregnancy or breastfeeding
  • Having had a heavy drinking episode (≥8 units) in the last 12 hours OR a breath alcohol reading above 35 µg/100 ml

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Quadruple

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Active Comparator: Probiotic Group
Capsules contain the active ingredient (live bacteria)
Dietary supplement: Probiotic Formula Capsule
A probiotic or placebo is randomly administered to patients with alcohol use disorder
Placebo Comparator: Placebo Group
Capsules look identical to the probiotic but contain no live bacteria
Dietary supplement: Probiotic Formula Capsule
A probiotic or placebo is randomly administered to patients with alcohol use disorder

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
38 participants with Alcohol Use Disorder assessed for Working Memory by n-back task
Time Frame: From enrollment to the end of the treatment at 4 weeks
Working memory will be assessed using a computerized N-back task (1-back, 2-back, 3-back conditions). Participants respond when a stimulus matches one presented previously (1-3 trials earlier). The task includes 50 trials per condition with 10 target stimuli. Each stimulus is presented for 1000 ms. Performance will be measured based on the number of commission errors (count) and number of correct responses (count), with higher correct responses indicating better working memory performance and higher commission errors indicating poorer performance.
From enrollment to the end of the treatment at 4 weeks
38 participants with Alcohol Use Disorder assessed for Gut Microbiome Composition by 16S rRNA Gene Sequencing
Time Frame: From enrollment to the end of the treatment at 4 weeks
Gut health will be assessed using 16S ribosomal RNA (rRNA) gene sequencing of stool samples collected and analysed in the laboratory. Microbial composition will be characterised using standard bioinformatics pipelines. Outcomes will include alpha diversity (within-sample diversity; e.g., Shannon diversity index) and beta diversity (between-sample differences in microbial composition). Performance will be measured as diversity indices (unitless values) and distance metrics for beta diversity, with higher alpha diversity generally indicating greater microbial diversity and gut health.
From enrollment to the end of the treatment at 4 weeks
38 participants with Alcohol Use Disorder assessed for Alcohol Craving by Penn Alcohol Craving Scale
Time Frame: From enrollment to the end of the treatment at 4 weeks
Alcohol craving will be assessed using the Penn Alcohol Craving Scale (PACS), a 5-item self-report questionnaire measuring frequency, intensity, and duration of alcohol cravings over the past week. Each item is rated on a scale from 0 to 6, yielding a total score ranging from 0 to 30. Performance will be measured as the total PACS score (range 0-30), with higher scores indicating greater alcohol craving severity.
From enrollment to the end of the treatment at 4 weeks
38 participants with Alcohol Use Disorder assessed for Response Inhibition by Go/No-Go task
Time Frame: From enrollment to the end of the treatment at 4 weeks
Response inhibition will be assessed using a computerized Go/No-Go task. Participants are required to respond to "go" stimuli and withhold responses to "no-go" stimuli. Performance will be measured as the number of commission errors (responses during no-go trials; count) and the number of correct responses (correct responses to go trials; count), with higher commission errors indicating poorer response inhibition and higher correct responses indicating better task performance.
From enrollment to the end of the treatment at 4 weeks

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
38 participants with Alcohol Use Disorder assessed for Depression, Anxiety, and Stress by Depression Anxiety Stress Scales-12
Time Frame: From enrollment to the end of the treatment at 4 weeks
Mental health symptoms will be assessed using the Depression Anxiety Stress Scales-12 (DASS-12), a 12-item self-report questionnaire measuring symptoms of depression, anxiety, and stress. Each item is rated on a 4-point Likert scale (0-3), yielding a total score ranging from 0 to 36. Performance will be measured as the total DASS-12 score (range 0-36), with higher scores indicating greater psychological distress.
From enrollment to the end of the treatment at 4 weeks
38 participants with Alcohol Use Disorder assessed for Drinking Behaviour by Loughborough Alcohol Drinking Questionnaire
Time Frame: From enrollment to the end of the treatment at 4 weeks

Drinking behaviour will be assessed using the Loughborough Alcohol Drinking Questionnaire (LoAD-Q), a 33-item self-report questionnaire measuring three dimensions: emotional drinking, external drinking, and restrained drinking. Each item is rated on a 5-point Likert scale (1 = never to 5 = very often). Subscale scores are calculated by summing item responses within each dimension.

The emotional drinking subscale (13 items) has a score range of 13 to 65, the external drinking subscale (10 items) ranges from 10 to 50, and the restrained drinking subscale (10 items) ranges from 10 to 50. Performance will be measured as subscale total scores, with higher scores indicating greater levels of emotional, external, and restrained drinking behaviour, respectively.
From enrollment to the end of the treatment at 4 weeks
38 participants with Alcohol Use Disorder assessed for Attention by Visual Search task
Time Frame: From enrollment to the end of the treatment at 4 weeks
Attention will be assessed using a computerized visual search task in which participants identify target stimuli among distractors. Performance will be measured as reaction time (milliseconds) and accuracy (percentage of correct responses, %) across trials, with lower reaction times indicating better attentional performance and higher accuracy indicating better task performance.
From enrollment to the end of the treatment at 4 weeks
38 participants with Alcohol Use Disorder assessed for Cognitive Bias by Rough Estimation Task
Time Frame: From enrollment to the end of the treatment at 4 weeks
Cognitive bias will be assessed using the Rough Estimation Task (REsT), where participants read a list of alcohol-related, semantically related, and unrelated words and estimate the proportion of alcohol-related words. Performance will be measured as the percentage (%) of words estimated as alcohol-related, with overestimation (>33%) indicating cognitive bias.
From enrollment to the end of the treatment at 4 weeks

Other Outcome Measures

Other Outcome Measures

For clinical trials, a planned measurement described in the protocol that is used to determine the effect of an intervention/treatment on participants. For observational studies, a measurement or observation that is used to describe patterns of diseases or traits, or associations with exposures, risk factors, or treatment. Types of outcome measures include primary outcome measure and secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
38 participants with Alcohol Use Disorder assessed for Inflammation by Salivary Interleukin-6 (IL-6) using Enzyme-Linked Immunosorbent Assay (ELISA)
Time Frame: From enrollment to the end of the treatment at 4 weeks
Inflammation will be assessed using salivary interleukin-6 (IL-6) measured via enzyme-linked immunosorbent assay (ELISA) using commercially available kits according to manufacturer protocols. Performance will be measured as IL-6 concentration in picograms per millilitre (pg/mL), with higher values indicating greater systemic inflammation.
From enrollment to the end of the treatment at 4 weeks
38 participants with Alcohol Use Disorder assessed for Disordered Eating by Eating Disorder Examination Questionnaire Short Form
Time Frame: From enrollment to the end of the treatment at 4 weeks
Disordered eating behaviours will be assessed using the Eating Disorder Examination Questionnaire Short Form (EDE-QS), a 12-item self-report questionnaire measuring eating disorder psychopathology over the past 7 days. Each item is rated on a 4-point scale (0-3), yielding a total score ranging from 0 to 36. Performance will be measured as the total EDE-QS score (range 0-36), with higher scores indicating greater severity of disordered eating behaviours.
From enrollment to the end of the treatment at 4 weeks
38 participants with Alcohol Use Disorder assessed for Physiological Stress by Salivary Cortisol using Enzyme-Linked Immunosorbent Assay (ELISA)
Time Frame: From enrollment to the end of the treatment at 4 weeks
Physiological stress will be assessed using salivary cortisol measured via enzyme-linked immunosorbent assay (ELISA) using commercially available kits according to manufacturer protocols. Performance will be measured as cortisol concentration in nanomoles per litre (nmol/L), with higher values indicating greater physiological stress.
From enrollment to the end of the treatment at 4 weeks
38 participants with Alcohol Use Disorder assessed for Gut Barrier Function by Caco-2 Cell Trans-Epithelial Electrical Resistance (TEER) and Scratch Assay Using Faecal Water Samples
Time Frame: From enrollment to the end of the treatment at 4 weeks
Gut barrier function will be assessed using in vitro assays applying cell-free faecal water prepared from participant stool samples to a Caco-2 intestinal epithelial cell model. Barrier integrity will be evaluated using trans-epithelial electrical resistance (TEER) measurements, and epithelial repair will be assessed using a scratch (wound healing) assay. Performance will be measured as TEER values (ohms·cm²) and percentage wound closure (%), with higher TEER values indicating improved barrier integrity and greater wound closure indicating enhanced epithelial repair capacity.
From enrollment to the end of the treatment at 4 weeks

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Loughborough University

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
Innovate UK

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
December 15, 2025

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
April 17, 2026

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
April 17, 2026

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
March 19, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
March 27, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
April 3, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
April 3, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
March 27, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
March 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 22834

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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