Effects of liraglutide on gut bacterial community dynamics

Liraglutide rapidly reshaped the gut bacterial community in diet-induced obese mice, favouring lactic acid-producing bacteria and reducing fermentative taxa; these shifts mostly reversed after a 7-day washout. Liraglutide also produced significant weight loss by day 4 that partially reversed post-treatment. The microbiome effects were diet-dependent, occurring in mice on a high-fat diet.

Journal article — controlled murine interventional study with washout. Population: diet-induced obese male C57BL/6J mice on high-fat or low-fat diets. Sample size: 24 male C57BL/6J mice. Follow-up: 21 days (14-day treatment plus 7-day washout). Interventions: liraglutide daily for 14 days.

Liraglutide produced significant weight loss by Day 4 that persisted during treatment and partially reversed post-washout. The gut bacterial community structure shifted distinctly during liraglutide treatment and mostly returned to baseline after 7-day washout. Among 21 ASVs identified as major contributors, 9 ASVs related to Lactobacillus gasseri, L. paragasseri, L. johnsonii and Leptogranulimonas caecicola increased with treatment and declined after washout, while 12 ASVs associated with Romboutsia, Faecalicatena and Oscillibacter decreased. Cross-group comparison identified 29 ASVs in seven phylogenetic groups, indicating enrichment of bile acid- and mucin-associated taxa and suppression of carbohydrate-fermentative genera.

For researchers studying liraglutide, this paper provides evidence that the drug alters gut microbial community structure in obese mice within days, with a reversible profile after washout and a high-fat-diet-dependent signature. It does not establish causality between microbiome shifts and metabolic benefits, and it does not demonstrate these effects in humans or at any specific liraglutide dose.

Key findings

Liraglutide induced significant weight loss by Day 4 that persisted during treatment and partially reversed after a 7-day washout.
Liraglutide treatment shifted the gut bacterial community structure, and the shifts mostly returned to baseline after the 7-day washout.
Of 21 major-contributor ASVs, 9 related to Lactobacillus gasseri, L. paragasseri, L. johnsonii and Leptogranulimonas caecicola increased during treatment and declined post-washout.
The remaining 12 ASVs, associated with Romboutsia, Faecalicatena and Oscillibacter, decreased during liraglutide treatment.
Across all groups, 29 ASVs clustered into seven phylogenetic groups, showing enrichment of bile acid- and mucin-associated taxa and suppression of carbohydrate-fermentative genera.
7.1 million 16S rRNA gene sequences were analysed from Illumina paired-end sequencing.

Limitations

Mouse model limits direct translation to humans
Small sample size (24 mice)
Short 21-day treatment and washout period
Microbiome shifts were not proven to cause liraglutide's metabolic effects

The record

Journal: Microbiology spectrum: e0034326
Published: 2026-08-03
PMID: 42545022 — DOI: 10.1128/spectrum.00343-26
Author countries: USA

Peptide profiles: Liraglutide.

All indexed evidence: Liraglutide trials & papers.