Tests probiotics for digestive side effects in adults with obesity starting GLP-1 medicines

Trial details

Who runs it

Hospices Civils de Lyon

Trial code

NCT07213323

Record updated

19 August 2026

Original description

Obesity is a prevalent chronic disease affecting 17% of the French population. Treatment involves multiple factors, with pharmacotherapy playing an increasingly important role. GLP-1 receptor agonists (GLP1 RAs) are considered revolutionary in obesity treatment, with three approved molecules available in France: liraglutide, semaglutide, and tirzepatide. These treatments, combined with a healthy lifestyle, induce significant weight loss: 9% with liraglutide, 15% with semaglutide, and 20% with tirzepatide.Read full original descriptionShow less

Evaluation of the Efficacy of Probiotics on Digestive Quality of Life in Patients Initiating GLP-1 Receptor Agonists for the Treatment of Obesity. A Randomized, Double-blind Trial

Obesity is a prevalent chronic disease affecting 17% of the French population. Treatment involves multiple factors, with pharmacotherapy playing an increasingly important role. GLP-1 receptor agonists (GLP1 RAs) are considered revolutionary in obesity treatment, with three approved molecules available in France: liraglutide, semaglutide, and tirzepatide. These treatments, combined with a healthy lifestyle, induce significant weight loss: 9% with liraglutide, 15% with semaglutide, and 20% with tirzepatide.

The most common adverse events (AEs) associated with GLP-1 RAs are gastrointestinal (GI) disorders, including nausea, vomiting, diarrhea, and abdominal pain. These AEs are dose-dependent and often decline over time. In phase 3 trials, semaglutide 2.4 mg showed higher rates of GI AEs compared to placebo, but most were mild to moderate and transient. GI AEs led to dose reduction or temporary treatment interruption in 12.5% of participants, with few permanent discontinuations.

Probiotics, are live microorganisms that benefit the host by improving gut microflora. Probiotics has been clinically proven to benefit gastrointestinal health. Probiotics may reduces symptoms of irritable bowel syndrome (IBS), improves gut barrier function, reduces inflammation, and decreases the incidence of C. difficile infection (CDI) in patients taking antibiotics.

Probiotics is therefore theorized to potentially reduce GI side effects associated with GLP-1 RA treatment for obesity.

Hypothesis Probiotics will prevent and limit the digestive disorders induced by GLP-1 R agonists, particularly during the dose escalation period. This would allow better digestive tolerance of the treatments, limiting the number of definitive treatment interruptions, facilitating compliance and dose escalation with a larger number of subjects at full dose and therefore with better systemic exposure to the compounds, a key factor in their effects on weight loss.

Inclusion: Patient who is going to start a GLP-1 RA (semaglutide or tirzepatide) for weight management; Men or Women; BMI ≥ 30 kg/m2 or BMI ≥ 27 kg/m2 associated with one or more co-morbidities (arterial hypertension, sleep apnea, dyslipidemia, arthritis); Between 18 and 75 years old; In the opinion of the investigator, the patient must have adequate support to comply with the entire study requirements as described in the protocol (e.g. transportation to and from trial site, ability to understand and fill the self-rating scales, drug compliance, availability to attend to the scheduled visits, etc…); Patient who agrees to be included in the study and who signs the informed consent form; Female participants of childbearing potential must agree to use effective contraception; Patient affiliated to a healthcare insurance plan.

Exclusion: Patients scheduled for bariatric surgery during the study period; Patients who have had bariatric surgery in the last 12 months; Patient with a current diagnosis of diabetes; Patients with a current diagnosis of liver cirrhosis, short bowel syndrome or inflammatory bowel disease (IBD); Clinically unstable medical disease, including cardiovascular, hepatic, renal, gastrointestinal, pulmonary, metabolic, endocrine, or other systemic disease; Product criteria:; Patient with known allergy to the product of the study; Prohibited treatments :; Current associated treatments or used in the last 30 days: GLP-1 RA, Anti-obesity drugs (AOD), Corticosteroids, Atypical neuroleptics, Antibiotics, Probiotics, Prebiotics; Regulatory criteria :; Persons under psychiatric care; Patients under 18 years old; Criteria relating to the study population:; Patient with contraindication to semaglutide or tirzepatide according to the Summary of Product Characteristics (SPC); Patients with severely weakened immune system; Persons deprived of their liberty by a judicial or administrative decision; Persons admitted to a health or social institution for purposes other than research; Adults subject to a legal protection measure (guardianship, curatorship); Persons not affiliated to a social security scheme or beneficiaries of a similar scheme; Subjects participating in other interventional research with an exclusion period still in progress at pre-inclusion.

ClinicalTrials.gov NCT07213323