Poop pills from skinny donors: a new weapon against obesity?
NCT ID NCT06268990
First seen Jun 27, 2026 · Last updated Jun 27, 2026
Summary
This completed pilot study tested whether transferring gut bacteria from lean donors or from people who had gastric bypass surgery could improve metabolism in 29 obese adults with prediabetes or diabetes. Participants received fecal transplants, and researchers measured changes in insulin sensitivity and blood sugar. The goal was to see if changing gut bacteria could help manage obesity and related conditions.
What this could mean
Our plain-language read of the trial. This is informational only, not medical advice or a prediction.
- Active substance
- fecal microbiota transplantation
- What this could lead to
- If it works, this could point toward a new way to treat obesity and related metabolic problems by changing gut bacteria.
- What could go wrong
- This is a small, early pilot study with only 29 people. Results may not apply to everyone, and the effects might be short-lived.
This is an AI summary of the original study and may miss details. Read our disclaimer.
Study facts
What this study's own registry entry says, in plain language.
- Phase
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Not a phased trial
Phase numbers describe drug development. The registry uses this when they do not apply, as it does for trials of devices, procedures or behaviour changes, and for observational studies.
- Participants
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29 people
The number who actually took part.
- Started
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Jan 2023
- Finished
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Apr 2026
- Lead sponsor
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Other sponsor
The registry's catch-all category, for sponsors it does not file as a company, a government agency, or a research network.
Who can take part
This study's own entry requirements. Only the study team can say for certain whether you qualify.
- Ages
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18 to 60 years
- Sex
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Anyone
- Healthy volunteers
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Accepted
You do not need to have the condition being studied to take part.
Show the full entry requirements Hide the full entry requirements
Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.
Inclusion Criteria: \- Inclusion criteria for patients * Age \>18 years * Morbid obesity defined by a BMI ≥ 40 kg/m2 * Prediabetes or diabetes with HbA1C between ≥ 5.7 % OR * Fasting plasma glucose \> 5.6 mmol/l (\> 100 mg/dl) (no caloric intake for at least 8 hours) OR * Random plasma glucose \> 11.1 mmol/l (\> 200 mg/dl) * Informed consent Inclusion criteria for RYGB-FMT intervention donors * Sustained total weight loss of ≥30% ≥12 months after RYGB surgery * HbA1c \< 6.5% without insulin treatment or oral antidiabetic medication * Age \>18 years * Informed consent Inclusion criteria for LEAN-FMT intervention donors * Normal weight (BMI ≥ 20 to \< 25 \>18 years * Informed consent Exclusion Criteria: Exclusion criteria for patients • Non-Compliance * Insulin dependent diabetes mellitus, treated with GLP-1 agonists or poorly controlled on oral antidiabetic medications (HbA1C \> 8%) * Use of any weight loss medication or participation in a weight loss program * History of recent body weight change (defined as body weight loss or body weight gain of ≥ 5 kg within the two months preceding study enrolment). * Use of immunosuppressive medication or immune modulators (glucocorticoids, methotrexate, tacrolimus, cyclosporine, thalidomide, interleukin-10 or -11) within the last three months preceding study enrolment. * Congenital or acquired immunodeficiencies. * Anatomical reconstruction of the nutrient passage (i.e. hemicolectomy, resection of small bowel, gastrectomy, sleeve gastrectomy, gastric bypass surgery, biliopancreatic diversion, fundoplication etc) or cholecystectomy. * Chronic diarrhoea * History of serious chronic disease including malignancy, rheumatic heart disease, endocarditis, or valvular disease (due to risk of bacteremia) * Any condition, based on clinical judgment that may make study participation unsafe * Pregnancy or Breast Feeding Exclusion criteria for RYGB-FMT intervention donors * Intake of pre-, pro- or antibiotics within \< 3 months before study entry * Use of immunosuppressive medication or immune modulators (glucocorticoids, methotrexate, tacrolimus, cyclosporine, thalidomide, interleukin-10 or -11) within the last three months preceding study enrolment. * Congenital or acquired immunodeficiencies. * Chronic or acute infectious diseases (specified under 6.2.1) * Drug abuse * Anatomical reconstruction of the nutrient passage other than surgical RYGB configuration (i.e. hemicolectomy, resection of small bowel, fundoplication, LSG-to-RYGB transformation etc) or cholecystectomy. * History of recent body weight change (defined as body weight loss or body weight gain of ≥ 5 kg within the two months preceding study enrolment). * Chronic diarrhoea or steatorrhea or acute gastrointestinal infection within ≤ 3 months before study entry. * History of serious chronic disease including malignancy, chronic kidney disease (eGFR \< 60 ml/min), heart failure (NYHA ≥ III). * Any further condition, based on clinical judgment that may disqualify the candidate as an appropriate donor. Exclusion Criteria for Lean-FMT Intervention Donors • History of overweight or obesity in the past (BMI \> 25 kg/m2) • History of recent body weight change (defined as body weight loss or body weight gain of ≥ 5 kg within the two months preceding study enrolment). • HbA1C \> 6.5% or treatment with insulin or oral anti-diabetic medication. • Use of any weight loss medication or participation in a weight loss program • Use of immunosuppressive medication or immune modulators (glucocorticoids, methotrexate, tacrolimus, cyclosporine, thalidomide, interleukin-10 or -11) within the last three months preceding study enrolment. • Congenital or acquired immunodeficiencies. • Chronic or acute infectious diseases (specified under 6.2.1) • Drug abuse • Anatomical reconstruction of the nutrient passage (i.e. hemicolectomy, resection of small bowel, fundoplication etc) or cholecystectomy. • Chronic diarrhoea or acute gastrointestinal infection within ≤ 3 months before study entry. • History of serious chronic disease including malignancy, chronic kidney disease (eGFR \< 60 ml/min), heart failure (NYHA ≥ III). • Any further condition, based on clinical judgment that may disqualify the candidate as an appropriate donor.
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Conditions
The condition(s) this trial relates to.
As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
Contacts and locations
Locations
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Department of Internal Medicine, Medical University Graz
Graz, 8010, Austria
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Other studies related to the condition(s) this trial covers.
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