Patients Using Olanzapine, Quetiapine, Risperidone or ClozapinePhase 2/3NGNGPNCT07606014
No Guts No Glory Probiotics
A Phase 2/3 study testing Probiotic Formula in people with Patients Using Olanzapine, Quetiapine, Risperidone or Clozapine, run by University Medical Center Groningen at 3 sites in Netherlands.
Trial summary
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… Read more about this study
- Who is it for?
- Ages 18 to 65 years
- Conditions the study is for
- Patients Using Olanzapine, Quetiapine, Risperidone or Clozapine
- What is being tested?
- Probiotic Formula
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 112 participants
- Where
- 3 sitesNetherlands
- Study dates
- 1 Jun 2026to 1 May 2029
- Phase
- Phase 2/3
- 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 65 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- About to start, or having started within the last 8 weeks, antipsychotic treatment with olanzapine, quetiapine*, clozapine or risperidone for treating psychosis
- Aged between 18 - 65
- 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)
- 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
Who cannot join
- 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
- 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
- Pregnancy or breastfeeding
- 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
Trial locations and contacts
3 sites in 1 country. Contact the study team or a site near you to ask about taking part.
Netherlands3 sites, 3 recruiting
- Recruiting
University Medical Center Groningen
Groningen, Provincie Groningen, 9713GZ
Toon A.W. Scheurink, MSc, +31681528283, a.w.scheurink@umcg.nl
Iris E.C. Sommer, MD, PhD
- Recruiting
KieN VIP Leeuwarden
Leeuwarden, Provincie Friesland, 8911KJ
Marrit Wiersma, +31614734656, marrit@kien.nu
Hesra Bijen, +31614734656, bijenhesra@gmail.com
- Recruiting
Antes Parnassia Groep
Rotterdam, South Holland, 3083AK
Yunus A.W. Yalcin, PhD, +310613434115, y.yalcin@parnassiagroep.nl
Nico van Beveren, MD, PhD
About this study
Official title: 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:
Read more
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
Read the 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.
- Being tested
- Probiotic Formula, Placebo
- Keywords
- Antipsychotics, Probiotics, Psychosis, Schizophrenia, Metabolic syndrome, HbA1c, Blood glucose, Weight gain, Olanzapine, Quetiapine, Risperidone, Clozapine
- Medical subject headings
- Psychotic Disorders, Schizophrenia, Metabolic Syndrome, Weight Gain
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Probiotic FormulaDietary supplement
Also called Ecologic Barrier
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
PlaceboDietary supplement
Also called Placebo formulation
- 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
| Study group | Role | What they receive |
|---|---|---|
| Probiotic intervention | Experimental | This group uses a probiotic formulation to prevent metabolic risk factors of antipsychotics Receives: Dietary Supplement: Probiotic Formula |
| Placebo | Placebo comparator | This group uses a placebo Receives: Dietary Supplement: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Hemoglobin A1C
Average blood glucose levels during the past 2 or 3 months
Measured: From enrollment to the end of treatment at 12 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted26 May 2026
- Study start1 Jun 2026 (estimated)
- Primary completion1 May 2029 (estimated)
- Study completion1 May 2029 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Patients Using Olanzapine, Quetiapine, Risperidone or ClozapineStudies of the same condition, open and under way.
- 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 2/3
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Single group
- Masking
- Triple blind
- Who is masked
- Participant, Care provider, Investigator
- Enrolment
- 112 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University Medical Center Groningen
- Sponsor type
- University, hospital or other
- Collaborators
- The Dutch Brain Foundation, Parnassia Groep, KienVIP
- Responsible party
- Sponsor
- Investigators
- Iris E.C. Sommer, Prof. Dr., Principal investigator, University Medical Center Groningen
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07606014
- Sponsor's protocol ID
- NL88832.042.25
- Acronym
- NGNGP
- Status last verified
- May 2026
- First submitted
- 18 May 2026
- Last updated
- 26 May 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Study at a glance
From the registry record, last updated by the sponsor on 26 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Probiotic Formulation to Prevent or Mitigate Antipsychotic Induced Metabolic Side-effects - A Multi-centre Randomized Placebo-controlled Double-blind Trial
- ClinicalTrials.gov ID
- NCT07606014
- Acronym / sponsor ID
- NGNGP / NL88832.042.25
- Keywords
- Antipsychotics, Probiotics, Psychosis, Schizophrenia, Metabolic syndrome, HbA1c, Blood glucose, Weight gain
- Phase
- Phase 2/3
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 112 participants (estimated)
- Lead sponsor
- University Medical Center GroningenUniversity, hospital or other
- Collaborators
- The Dutch Brain Foundation, Parnassia Groep, KienVIP
- Study start
- 1 Jun 2026 (estimated)
- Primary completion
- 1 May 2029 (estimated)
- Study completion
- 1 May 2029 (estimated)
- First posted
- 26 May 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 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
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 design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Single group
- Masking
- Triple blind (participant, care provider, investigator)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Probiotic intervention | Experimental | Dietary Supplement: Probiotic FormulaThis group uses a probiotic formulation to prevent metabolic risk factors of antipsychotics |
| Placebo | Placebo comparator | Dietary Supplement: PlaceboThis group uses a placebo |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (5 listed)
- About to start, or having started within the last 8 weeks, antipsychotic treatment with olanzapine, quetiapine*, clozapine or risperidone for treating psychosis
- Aged between 18 - 65
- 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)
- The participant understands the study and is able to provide written informed consent.
Key exclusion criteria (4 listed)
- 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
- 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
- Pregnancy or breastfeeding
- 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
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 |
|---|---|---|
| Probiotic FormulaAlso: Ecologic BarrierAfter 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 | Dietary supplement | Probiotic intervention |
| PlaceboAlso: Placebo formulation* 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 | Dietary supplement | Placebo |
Primary outcome
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
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 26 May 2026.
- Individual participant dataSharing planned: Undecided
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.
Iris E.C. Sommer, Prof. Dr. principal investigator
University Medical Center Groningen
3 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2/3 study testing Probiotic Formula in people with Patients Using Olanzapine, Quetiapine, Risperidone or Clozapine, run by University Medical Center Groningen at 3 sites in Netherlands.
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 5 inclusion and 4 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: looking for participants now, as of the sponsor's last update on 26 May 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 3 sites in Netherlands. 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. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this combined phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
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 Toon A.W. Scheurink, MSc (+31681528283, a.w.scheurink@umcg.nl), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Hemoglobin A1C (time frame: From enrollment to the end of treatment at 12 weeks). 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 26 May 2026.