Supplements · Metabolic & Cardiometabolic · Gut & Microbiome
Lactobacillus reuteri increases GLP-1
In plain terms: Does the probiotic L. reuteri raise the appetite-and-blood-sugar hormone GLP-1?
Yes in one small human trial, but it rests on just 21 people and didn't improve insulin sensitivity or weight.
📅 Last reviewed: 2026-07-15 ⓘ
Evidence ladder
How far up the ladder this claim has climbed. A high consensus on a low rung means "consistent so far," not "proven in people."
Top evidence so far: Human trials (RCT / n-of-1)
How the studies fall
What the evidence shows
L. reuteri SD5865 raised GLP-1 and GLP-2 release and insulin/incretin secretion in glucose-tolerant adults — the single best human-grade taxon->GLP-1 signal, but n=21 and no change in insulin sensitivity or weight.
The evidence (9)
| Source | Grade | Stance | Quality | Finding |
|---|---|---|---|---|
| Hsieh 2013 · Nutr Metab | animal | supports | low | L. reuteri GMNL-263 improved insulin resistance in high-fructose rats (GLP-1 indirect) |
| Natividad 2018 · Cell Metabolism | animal | supports | moderate | AhR-ligand Lactobacillus strain improves glucose dysmetabolism in mice via enhanced intestinal GLP-1 secretion |
| Nilsson 2016 · Clin Nutr ESPEN | RCT | mixed | low | Commercial probiotic mix (incl lactobacilli) did not consistently augment barley-induced GLP-1 in humans |
| Verma 2026 · Probiotics Antimicrob Proteins | observational | mixed | low | Systematic review finds skin-derived Bifidobacterium (not L. reuteri) can stimulate GLP-1, indirect and off-organism support only. |
| Lai 2024 · npj Biofilms Microbiomes | animal | contradicts | moderate | Colonizing L. reuteri in microbiota-deficient mice SUPPRESSED elevated GLP-1 (directionally opposite the claim) |
| Wang JX et al 2025 · study_type: animal | animal | mixed | moderate | L. reuteri gavage in HFD/db-db mice raised fecal eicosatrienoic acid, which promoted GLP-1 secretion via CD36/PLC/IP3R/Ca2+ in intestinal cells, improving glucose homeostasis; in-vitro STC-1 cells confirmed. |
| Simon MC, et al. (Holst) 2015 · Diabetes Care | RCT | supports | moderate | [FT-verified] SD5865 DB-RCT n=21 +76% GLP-1 P<.01 +49% insulin; key human positive |
| Zeng 2024 · mBio | observational | supports | low | [FT-verified] mBio review microbiota-GLP1 crosstalk; mechanistic only |
| Tenorio-Jiménez 2018 · BMC Complement Altern Med | RCT | tested-null | low | RCT of L. reuteri V3401 in obese metabolic-syndrome adults found no significant improvement in insulin-resistance/incretin markers, tempering the GLP-1 claim. |
Disagree, or know a study we missed?
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Educational only, not medical advice. Grades and scores reflect published evidence weighted by study design and quality; see the methodology.