Food Contaminants · Gut & Microbiome
glyphosate alters gut microbiome
In plain terms: Does glyphosate damage your gut bacteria?
Contested Food Contaminants 🐭 Non-human evidence🔬 Includes disconfirming
Part of: 🔍 glyphosate
RefutedContestedStrong support
consensus score -0.08
The theory is sound, because gut bacteria have the exact pathway glyphosate blocks. But it has never been tested in a single human. The evidence is rodents, mostly at doses far above anything you would eat.
📅 Last reviewed: 2026-07-29 ⓘ
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: Animal studies (Animal)
MechanismIn-vitroAnimalObservationalRCTMeta-analysis
How the studies fall
3 support 2 contradict 0 tested null 25 mixed · 30 sources, 5 independent groups
What the evidence shows
The mechanism is genuinely plausible: glyphosate blocks the shikimate pathway, gut bacteria have that pathway and humans do not, and sensitivity varies by bacterial strain. But the evidence is almost entirely animal, at doses far above human dietary exposure, and there is NO human gut-microbiome study at all.
The evidence (30)
| Source | Grade | Stance | Quality | Finding |
|---|---|---|---|---|
| Matsuzaki R et al 2026 · study_type: animal | animal | mixed | moderate | Mice given glyphosate via drinking water at the regulatory reference dose for 7 weeks showed altered gut microbiota composition and gut-barrier changes, with male-specific anxiety/social-behavior effects; microbiota transplant from exposed TEMPERED: preclinical (animal/in-vitro) evidence, retained in the ledger but not carrying a human-outcome headline; dosing is typically far above human exposure. |
| Zheng J et al 2026 · study_type: animal | animal | mixed | low | Zebrafish intestinal exposure to glyphosate (not AMPA) increased antibiotic-resistance-gene (ARG) relative abundance 1.67-fold, rising to 2.30-fold with co-exposure to oxytetracycline (dose/route not quantified). Measures gut resistome/ARG TEMPERED: preclinical (animal/in-vitro) evidence, retained in the ledger but not carrying a human-outcome headline; dosing is typically far above human exposure. |
| Mazuryk J et al 2024 · Ecotoxicology and environmental safety | observational | supports | low | Narrative review of preclinical AND clinical evidence on glyphosate/GBH effects on the microbiota-gut-brain axis, concluding GBH exposure causes dysbiosis, GI symptoms, and neuro-behavioral effects, and claiming to be the 'first survey' of |
| Xue-Dong H et al 2026 · study_type: animal | animal | mixed | low | Rana dybowskii tadpoles exposed to glyphosate and/or ZnO nanoparticles (freshwater, concentrations unspecified) showed individually and synergistically altered gut microbiota alpha/beta diversity and an elevated dysbiosis index via 16S sequ |
| Houmenou CT et al 2025 · preprint | animal | contradicts | low | Termite (Trinervitermes spp., field colonies) 16S metabarcoding found glyphosate-treated vs untreated colonies showed NO significant difference in gut alpha or beta diversity, though untreated samples trended toward higher richness. Clean f |
| d10-3389-fenvh-2026-1863758 2026 · Frontiers in Environmental Health | observational | mixed | low | Perspective/opinion piece (Frontiers in Environmental Health) drawing a DDT-safety-history analogy and citing 'emerging evidence' and 'mechanistic insights from microbiome science' linking glyphosate to disease, but reports no new primary d |
| Sun J et al 2026 · study_type: animal | animal | mixed | low | Sea cucumber dietborne exposure via feed matrix at 8.66-6960 mg/kg feed (72h) produced only 'subtle' gut microbiota compositional shifts detectable mainly at fine taxonomic resolution, with alpha-diversity largely unchanged and predicted fu |
| Tall T et al 2026 · bioRxiv | mechanism | mixed | low | Bioinformatic analysis (no glyphosate dosing performed) classified human gut microbiome and ATGC bacterial genomes by EPSPS glyphosate-sensitivity (via EPSPSClass) and found sensitive strains carry more AMR-gene diversity while resistant st |
| Li G et al 2025 · Human & experimental toxicology | animal | mixed | moderate | Mice given glyphosate at 50, 250, or 500 mg/kg/day orally for 30 days showed dose-related gut microbiota shifts (decreased Patescibacteria, 11 genera altered) and serum metabolomic changes linked to hepatic injury. Doses are 30-300x the EPA TEMPERED: preclinical (animal/in-vitro) evidence, retained in the ledger but not carrying a human-outcome headline; dosing is typically far above human exposure. |
| Liu JB et al 2026 · study_type: animal | animal | mixed | moderate | Mice given dietary glyphosate at the regulatory 'safe' level in a DSS-colitis model showed gut dysbiosis (increased Bacteroides thetaiotaomicron) driving palmitic-acid/JAK-STAT-mediated colitis worsening; effect was in a disease (DSS-induce TEMPERED: preclinical (animal/in-vitro) evidence, retained in the ledger but not carrying a human-outcome headline; dosing is typically far above human exposure. |
| Duan T et al 2024 · study_type: animal | animal | mixed | moderate | Rats given Roundup at 500 mg/kg body weight orally showed gut microbial dysbiosis, oxidative stress, and colonic inflammation (IL-6 up 3.29-fold, IL-1beta up 0.65-fold), independent of aromatic-amino-acid deficiency; fecal microbiota transp TEMPERED: preclinical (animal/in-vitro) evidence, retained in the ledger but not carrying a human-outcome headline; dosing is typically far above human exposure. |
| Liu J et al 2025 · study_type: animal | animal | mixed | moderate | Laying hens fed glyphosate at 47 mg/kg body weight/day (described as 'below no-observed-adverse-effect-level') for 6 weeks in a fatty-liver-disease model showed gut dysbiosis (decreased Lactobacillus/Bifidobacterium, increased Escherichia-S TEMPERED: preclinical (animal/in-vitro) evidence, retained in the ledger but not carrying a human-outcome headline; dosing is typically far above human exposure. |
| Barnett JA et al 2025 · study_type: animal | animal | mixed | moderate | Mice given glyphosate via drinking water at dietary-relevant levels (0.01 mg/kg/day, Average American Diet) or the EPA's acceptable daily intake (1.75 mg/kg/day) during mating/gestation showed gut microbiome shifts (altered Akkermansia muci TEMPERED: preclinical (animal/in-vitro) evidence, retained in the ledger but not carrying a human-outcome headline; dosing is typically far above human exposure. |
| Fenech K et al 2025 · preprint | observational | mixed | low | Narrative review covering glyphosate plus 3 other EU-approved pesticides, synthesizing epidemiological, animal, and in-vitro evidence linking pesticide exposure (including general-population background exposure, not just occupational) to gu |
| Maddalon A et al 2025 · study_type: observational | observational | mixed | low | HUMAN study: 26 occupationally-exposed Italian vineyard workers, pre/post glyphosate application, showed shifted cytokine profiles (increased IL-4/IL-5, Th1->Th2 shift) and a slight drop in plasma LPS, which authors interpret as 'hinting at |
| Ignácio ADC et al 2024 · Food & function | animal | mixed | moderate | PRISMA-based systematic review (using SYRCLE, an ANIMAL-study risk-of-bias tool) of glyphosate/GBH effects on intestinal microbiota, metabolism, and gut microstructure concluded consistent findings of induced dysbiosis, altered intestinal p TEMPERED: preclinical (animal/in-vitro) evidence, retained in the ledger but not carrying a human-outcome headline; dosing is typically far above human exposure. |
| Vardazaryan N et al 2026 · Scientific Reports | animal | mixed | moderate | Global meta-analysis of honeybee (insect) gut microbiome across 7 regions found glyphosate exposure linked to disruption of core taxa (Snodgrassella alvi) alongside enrichment of Pseudomonas (hypothesized glyphosate-degrading), interpreted TEMPERED: preclinical (animal/in-vitro) evidence, retained in the ledger but not carrying a human-outcome headline; dosing is typically far above human exposure. |
| Muñoz JP et al 2025 · study_type: observational | observational | supports | low | Narrative review of honeybee/bumblebee gut microbiota literature concludes glyphosate 'can alter the gut microbiome in some bee species' but effects are highly variable by species, exposure conditions, and formulation, with surfactants in c |
| Sun J et al 2026 · study_type: animal | animal | mixed | moderate | Sea cucumber (marine invertebrate) waterborne exposure (measured 0.09-4.49 mg/L, 24h, low/med/high) shifted gut 16S alpha diversity (Shannon p=0.0497, Simpson p=0.0484) and beta diversity (PERMANOVA p=0.008), with mortality (36.7%) only at TEMPERED: preclinical (animal/in-vitro) evidence, retained in the ledger but not carrying a human-outcome headline; dosing is typically far above human exposure. |
| Zheng J et al 2026 · study_type: animal | animal | mixed | low | Zebrafish exposed to glyphosate/AMPA and oxytetracycline (aquatic, dose unspecified) showed gut dysbiosis (raised Firmicutes/Bacteroidetes ratio) linked to liver lipid accumulation and inflammation via the gut-liver axis; combined exposure TEMPERED: preclinical (animal/in-vitro) evidence, retained in the ledger but not carrying a human-outcome headline; dosing is typically far above human exposure. |
| Afridi R et al 2026 · study_type: animal | animal | mixed | low | Zebrafish 21-day co-exposure to polyethylene microplastics + glyphosate (concentration unspecified) via 16S rRNA sequencing showed glyphosate alone significantly enriched Aeromonas hydrophila in gut, with combined exposure causing the large TEMPERED: preclinical (animal/in-vitro) evidence, retained in the ledger but not carrying a human-outcome headline; dosing is typically far above human exposure. |
| Su Z et al 2026 · study_type: animal | animal | contradicts | moderate | Predatory insect (Arma chinensis) given a field-recommended glyphosate concentration (3.5 g/L) showed reduced growth/reproduction, but gut bacterial abundance shifts were NOT statistically significant and overall microbiota diversity remain |
| Vardazaryan N et al 2025 · preprint | animal | mixed | moderate | Honeybee gut microbiome meta-analysis/co-abundance-network study across 8 published studies + new Armenia 16S data found glyphosate disrupted core gut taxa, with stronger effects in newly-emerged bees under prolonged exposure, and enrichmen TEMPERED: preclinical (animal/in-vitro) evidence, retained in the ledger but not carrying a human-outcome headline; dosing is typically far above human exposure. |
| Romero-Alfano I et al 2026 · study_type: animal | animal | mixed | low | Daphnia magna (invertebrate) exposed to glyphosate at ppb-ppt concentrations (near environmentally-relevant, not human dietary) showed altered gut microbiome by 16S rDNA sequencing, correlated with neurotransmitter changes and reduced repro TEMPERED: preclinical (animal/in-vitro) evidence, retained in the ledger but not carrying a human-outcome headline; dosing is typically far above human exposure. |
| Malinoski L et al 2026 · study_type: observational | observational | supports | low | Narrative review (host-associated + environmental microbiomes, species/dose unspecified) concludes glyphosate exposure is associated with 'microbiome restructuring... often without major shifts in overall diversity,' but states this evidenc |
| Zhang Q et al 2024 · Journal of agricultural and food chemistry | animal | mixed | low | Soil invertebrate (Enchytraeus crypticus) exposed to glyphosate (dose/route not quantified in abstract) showed gut microbiota disorder plus increased abundance of antibiotic-resistance determinants, alongside oxidative stress and detoxifica TEMPERED: preclinical (animal/in-vitro) evidence, retained in the ledger but not carrying a human-outcome headline; dosing is typically far above human exposure. |
| Wu Y et al 2026 · study_type: animal | animal | mixed | low | Honeybees co-exposed to polystyrene microplastics + glyphosate (20 days, oral/dietary, concentrations unspecified) showed midgut damage and microbial dysbiosis alongside cognitive/behavioral impairment. Co-exposure design cannot isolate gly |
| Cáceres-Chacón M et al 2025 · study_type: animal | animal | mixed | moderate | Rats given oral glyphosate at 'a dose considered safe' for 16 weeks showed increased anxiety-like behavior (elevated plus maze) and 16S-confirmed gut microbiota changes, specifically decreased Lactobacillus, a serotonin-linked genus. Author TEMPERED: preclinical (animal/in-vitro) evidence, retained in the ledger but not carrying a human-outcome headline; dosing is typically far above human exposure. |
| Manandhar I et al 2026 · bioRxiv | animal | mixed | low | Mouse study (oral glyphosate exposure, dose not stated) found gut microbiota causally mediates glyphosate-induced hypertension via FXR-signaling disruption and accumulation of the microbial metabolite shikimic acid. Preprint (bioRxiv, not p TEMPERED: preclinical (animal/in-vitro) evidence, retained in the ledger but not carrying a human-outcome headline; dosing is typically far above human exposure. |
| Yang H et al 2025 · Journal of hazardous materials | animal | mixed | low | Soil invertebrate (Enchytraeus crypticus) gut microbiome, exposed to glyphosate at 'environmentally relevant concentrations' (exact dose not given) alone or with microplastics, showed glyphosate primarily reduced gut microbial diversity and TEMPERED: preclinical (animal/in-vitro) evidence, retained in the ledger but not carrying a human-outcome headline; dosing is typically far above human exposure. |
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