No Guts No Glory Probiotics (NGNGP)

May 18, 2026 updated by: University Medical Center Groningen

Probiotic Formulation to Prevent or Mitigate Antipsychotic Induced Metabolic Side-effects - A Multi-centre Randomized Placebo-controlled Double-blind Trial

The goal of this clinical trial is to learn if probiotics work to prevent or reduce metabolic side effects caused by antipsychotic medication in adults.

The main question it aims to answer is:

Do probiotics reduce weight gain, blood sugar levels, and blood fat levels in people using antipsychotics?

Researchers will compare a probiotic (Ecologic® Barrier) to a placebo (a look-alike powder without active bacteria) to see if the probiotic is effective.

Participants will:

Take either probiotics or a placebo daily for 12 weeks (3 months) Dissolve two sachets in water and drink them each morning Visit the clinic (or receive home visits) four times: at the start, after 6 weeks, and after 12 weeks, plus an initial screening visit Undergo physical measurements (e.g., weight, blood pressure), complete questionnaires, and perform a cognitive test at specific visits Provide blood samples and stool samples at the beginning and end of the study Complete two 3-day food diaries during the study

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

Antipsychotic medications such as olanzapine, quetiapine, clozapine, and risperidone are widely used for the treatment of psychotic and mood disorders. Although effective, these medications are frequently associated with adverse metabolic effects, including weight gain, increased blood glucose levels, and dyslipidemia. These side effects can negatively impact physical health and increase the risk of cardiovascular disease and diabetes.

Emerging evidence suggests that the gut microbiome may play a role in metabolic regulation and that modulation of gut microbiota through probiotics could mitigate antipsychotic-induced metabolic disturbances. Probiotics are live microorganisms that, when administered in adequate amounts, may confer health benefits by improving gut barrier function and influencing metabolic processes.

This study is a randomized, double-blind, placebo-controlled clinical trial designed to investigate the efficacy and safety of a multispecies probiotic formulation (Ecologic® Barrier) in preventing or reducing metabolic side effects in patients initiating treatment with antipsychotic medication. A total of 112 participants will be enrolled and randomly assigned to receive either the probiotic or a placebo for a duration of 12 weeks.

The investigational product consists of a powder formulation containing nine bacterial strains, administered as two sachets dissolved in water once daily in the morning. The placebo consists of an inert powder (e.g., maize starch and maltodextrin) with identical appearance and administration schedule. Participants, investigators, and study personnel will remain blinded to treatment allocation throughout the study.

Participants will continue their standard psychiatric treatment, including antipsychotic and/or mood-stabilizing medication, with minimal changes where possible. Concomitant use of additional psychotropic medications such as a second antipsychotic, lithium, or antiepileptic drugs is permitted.

Study procedures include baseline, interim (6 weeks), and end-of-study (12 weeks) assessments. These assessments involve physical measurements (e.g., body weight, waist and hip circumference, blood pressure), laboratory analyses of metabolic parameters using blood samples, and stool sample collection for microbiome-related analyses. In addition, participants will complete validated questionnaires assessing quality of life, eating behavior, and gastrointestinal symptoms, as well as cognitive testing at baseline and study completion.

Dietary intake will be monitored using two 3-day food diaries (pre-intervention and prior to the final visit) to account for potential dietary influences on metabolic outcomes and gut microbiota.

The primary objective is to evaluate whether probiotic supplementation reduces antipsychotic-induced metabolic disturbances compared to placebo. Secondary objectives include assessing safety and tolerability, as well as exploring changes in gastrointestinal symptoms, cognitive functioning, and potential microbiome-related mechanisms.

The total study duration per participant is approximately 3 months, with an additional optional one-month post-study probiotic use. After study completion, treatment allocation will be unblinded. Participants will be monitored throughout the study for adverse events, with particular attention to gastrointestinal symptoms, which are expected to be mild and transient.

This study aims to provide further evidence on the role of probiotics as a low-risk, adjunctive intervention to improve metabolic health in patients treated with antipsychotic medication.

Study Type

Interventional

Enrollment (Estimated)

112

Phase

  • Phase 2
  • Phase 3

Contacts and Locations

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

Study Contact

Study Locations

  • Netherlands
    • Provincie Friesland
      • Leeuwarden, Provincie Friesland, Netherlands, 8911KJ
        • Recruiting
        • KieN VIP Leeuwarden
        • Contact:
        • Contact:
        • Principal Investigator:
          • Nynke Boonstra, PhD
    • Provincie Groningen
      • Groningen, Provincie Groningen, Netherlands, 9713GZ
        • Recruiting
        • University Medical Center Groningen
        • Contact:
        • Principal Investigator:
          • Iris E.C. Sommer, MD, PhD
    • South Holland
      • Rotterdam, South Holland, Netherlands, 3083AK
        • Recruiting
        • Antes Parnassia Groep
        • Contact:
        • Principal Investigator:
          • Nico van Beveren, MD, PhD

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

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. About to start, or having started within the last 8 weeks, antipsychotic treatment with olanzapine, quetiapine*, clozapine or risperidone for treating psychosis
  2. Aged between 18 - 65
  3. No exposure to these four antipsychotic medications for longer than one week continuously in the last 6 months (except starting the treatment with the current medication 8 weeks prior to the inclusion)

  4. The participant understands the study and is able to provide written informed consent.

    • Quetiapine prescribed in a low dose for use as a sleep aid does not apply

Exclusion Criteria:

  1. Critically ill patients (e.g. ICU), diagnosed comorbid eating disorders, chronic GI-disorders, disorders of the liver or pancreas, pre-existing diagnosed diabetes mellitus or metabolic syndrome
  2. Current use of medications known to target metabolism or weight (e.g, diabetes medication and GLP-1 agonists, proton pump inhibitors and diuretics/beta blockers) or use of antibiotics or probiotics (such as Yakult, Activia, or other probiotic supplements containing ≥10⁹ CFUs) in the past 4 weeks
  3. Pregnancy or breastfeeding
  4. Inability to follow the intervention or other conditions that according to the investigator might interfere with the evaluation of the study objectives as judged by the treating physician

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: Prevention
  • Allocation: Randomized
  • Interventional Model: Single Group Assignment
  • Masking: Triple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Probiotic intervention
This group uses a probiotic formulation to prevent metabolic risk factors of antipsychotics
Dietary supplement: Probiotic Formula

After informed consent, participants will be randomized 1:1 to either:

  • Intervention group: Ecologic® Barrier
  • Control group: Placebo powder (identical in appearance, taste, and packaging but without active bacterial strains)

Ecologic® Barrier

  • Dosage form: Powder formulation containing a multi-strain probiotic mixture
  • Dosage: Standard manufacturer-recommended dose per sachet
  • Frequency: Twice daily (morning and evening)
  • Route of administration: Oral, dissolved in water or another non-carbonated beverage
  • Duration: 12 weeks (3 months)
  • Distinguishing characteristics:
  • Contains a defined combination of probiotic strains specifically formulated to support gut ba- rrier integrity
  • Delivered as a powder sachet to ensure stability of live bacterial cultures
  • Designed to modulate gut-brain axis pathways relevant to antipsychotic-associated metabolic effects
Other Names:
  • Ecologic Barrier
Placebo Comparator: Placebo
This group uses a placebo
Dietary supplement: Placebo
  • Dosage form: Powder identical in appearance, texture, and packaging to the active product
  • Dosage: One sachet per administration
  • Frequency: Twice daily
  • Route of administration: Oral
  • Duration: 12 weeks
  • Distinguishing characteristics:
  • Contains no active probiotic strains
  • Formulated to match the organoleptic properties of Ecologic® Barrier to maintain blinding
Other Names:
  • Placebo formulation

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Hemoglobin A1C
Time Frame: From enrollment to the end of treatment at 12 weeks
Average blood glucose levels during the past 2 or 3 months
From enrollment to the end of treatment at 12 weeks

Collaborators and Investigators

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

Sponsor

University Medical Center Groningen

Collaborators

Parnassia Groep
The Dutch Brain Foundation (funding)
KienVIP

Investigators

  • Principal Investigator: Iris E.C. Sommer, Prof. Dr., University Medical Center Groningen

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 (Estimated)

June 1, 2026

Primary Completion (Estimated)

May 1, 2029

Study Completion (Estimated)

May 1, 2029

Study Registration Dates

First Submitted

May 18, 2026

First Submitted That Met QC Criteria

May 18, 2026

First Posted (Actual)

May 26, 2026

Study Record Updates

Last Update Posted (Actual)

May 26, 2026

Last Update Submitted That Met QC Criteria

May 18, 2026

Last Verified

May 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • NL88832.042.25

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.

Clinical Trials on Probiotic Formula

Search Similar Trials

Sponsors and Collaborators

Medical Conditions

Drug Interventions

CROs by country

CROs in Italy

Conditions

Rare Diseases

Drug Interventions

Dietary Supplements

Sponsor/Collaborators

Locations

Subscribe