Glyphosate is the most widely used herbicide in human history. Since Monsanto introduced Roundup in 1974, and particularly since the introduction of Roundup Ready genetically modified crops in 1996, global glyphosate use has increased by approximately 15-fold. In the UK, it is applied to wheat, oats, barley, oilseed rape, and numerous other crops — and since 2022 it has also been approved for use in urban green spaces, parks, and roadsides. You are consuming it. The question that matters clinically is not whether — it is what it does once it gets inside you, and whether the regulatory framework designed to tell us it is safe has actually answered that question.
The short answer is that it has not. The regulatory safety assessment for glyphosate is based primarily on its intended mechanism of action — inhibition of the EPSPS enzyme in the shikimate pathway, which plants and some bacteria use to synthesise aromatic amino acids. Humans do not have the shikimate pathway. Therefore, the regulatory conclusion runs, glyphosate cannot directly harm human cells in the way it kills plants.
This framing has one significant problem: your gut microbiome does have the shikimate pathway. And glyphosate is a mineral chelator that operates entirely separately from EPSPS inhibition. These two mechanisms — microbiome disruption and mineral chelation — produce downstream effects that the original safety framework was never designed to capture, and that nobody with the power to change the regulatory conclusion has a financial interest in funding research to investigate properly.
Glyphosate is not just a herbicide.
It is also a broad-spectrum antibiotic and mineral chelator.
Glyphosate was first patented not as a herbicide but as a chelating agent — a compound that binds to metal ions. Its original US patent (1964, Stauffer Chemical Company) described it as a descaling agent for industrial pipes — it bound to calcium, magnesium, manganese, zinc, and iron deposits and stripped them away. Monsanto subsequently discovered its herbicidal properties and patented it for agricultural use.
The chelating mechanism never went away. Glyphosate binds to divalent cations in soil, reducing mineral bioavailability to plants. It binds to the same minerals in biological systems — including the human gut lumen, where manganese, zinc, iron, and cobalt are essential cofactors for hundreds of enzymatic processes.
The antibiotic mechanism was patented by Monsanto in 2010 — US Patent 7,771,736 — as a method of treating infections in animals and humans using glyphosate as an antimicrobial agent. This patent exists. The regulatory agencies that approved glyphosate as safe decades earlier did not assess its safety as an antibiotic compound, because it was not approved as one.
The regulatory gap at the centre of this
Glyphosate was approved as a herbicide based on safety data generated for a herbicide. Its mechanism as a mineral chelator and its antimicrobial properties — both patented separately — were never part of the primary safety assessment framework. This is not a conspiracy. It is a regulatory system designed around the compound's stated use, not its full biochemical activity in biological systems. Subsequent evidence of these alternative mechanisms has not triggered reassessment because the regulatory burden of proof runs in the wrong direction: industry must prove safety to a standard set before these mechanisms were characterised, not to a standard informed by what we now know.
Your gut bacteria have the pathway
glyphosate is designed to destroy.
The shikimate pathway — the enzymatic route glyphosate blocks in plants — is present in bacteria, fungi, and some parasites. It is absent in human cells. This is the basis of the standard safety claim. What the claim omits is that your gut microbiome contains trillions of bacterial organisms, many of which rely on the shikimate pathway for amino acid synthesis.
Glyphosate's differential toxicity to gut bacteria has been characterised in several studies. The pattern that emerges is consistent with a broad-spectrum antibiotic selectively targeting bacteria that rely on the shikimate pathway — which includes many of the Lactobacillus, Bifidobacterium, and Akkermansia species associated with gut barrier integrity, immune regulation, and neurotransmitter synthesis.
"The organisms that appear most sensitive to glyphosate disruption are not pathogens. They are the commensal bacteria most associated with health — the species that produce short-chain fatty acids, maintain the gut lining, and regulate immune tolerance."
The organisms that appear more resistant are, disproportionately, opportunistic pathogens — Clostridium, certain Salmonella strains, and Enterococcus species. A herbicide that preferentially suppresses beneficial bacteria while leaving pathogenic ones relatively unharmed is, functionally, a slow-acting prebiotic for dysbiosis.
The downstream effects of this selective pressure on the microbiome connect to almost every system that functional testing assesses:
- Gut barrier integrity — Akkermansia muciniphila, which maintains the mucus layer protecting the gut lining, is particularly sensitive to glyphosate. Reduced Akkermansia correlates with increased intestinal permeability. Zonulin — the protein marker of leaky gut — rises when Akkermansia falls.
- Short-chain fatty acid production — Butyrate-producing bacteria (Faecalibacterium prausnitzii, Roseburia) are among the most glyphosate-sensitive species. Butyrate is the primary fuel for colonocytes, the regulator of colonic inflammation, and an epigenetic modifier. Its depletion cascades into mucosal inflammation and impaired gut immune function.
- Neurotransmitter synthesis — approximately 90% of serotonin is produced in the gut by enterochromaffin cells, guided by microbial signals. Tryptophan metabolism toward serotonin requires healthy Lactobacillus populations. Dysbiosis shifts tryptophan toward the kynurenine pathway — associated with depression, inflammation, and neurotoxic metabolite production.
- Immune regulation — the gut microbiome trains immune tolerance. Dysbiosis driven by antibiotic-like compounds disrupts Treg/Th17 balance, increasing susceptibility to autoimmunity. The connection between gut dysbiosis and autoimmune conditions — Hashimoto's, rheumatoid arthritis, multiple sclerosis — is one of the more robustly established areas of microbiome research.
- Oestrogen clearance — beta-glucuronidase activity in the gut, which determines oestrogen recirculation, is microbiome-dependent. Dysbiosis alters the oestrogen enterohepatic circulation, contributing to oestrogen dominance patterns independent of what the ovaries are producing.
It binds the minerals your enzymes
cannot function without.
The mineral chelation mechanism is, in some ways, the more tractable clinical concern — because its downstream effects are measurable, dose-dependent, and mechanistically coherent even where direct causation from dietary glyphosate exposure has not been established in humans.
Glyphosate has a particularly high affinity for manganese, zinc, cobalt, and iron — binding them in both soil and biological systems and reducing their bioavailability. The minerals it preferentially chelates are not metabolically peripheral. They are central cofactors for processes that appear in almost every system of functional medicine assessment:
| Mineral | Key enzymatic roles | Functional consequence of depletion |
|---|---|---|
| Manganese | Mitochondrial superoxide dismutase (MnSOD), arginase, glutamine synthetase, MTHFR cofactor | Oxidative stress, impaired urea cycle, glutamate excess, impaired folate conversion |
| Zinc | MTHFR activity, >300 enzyme cofactor roles, immune cell production, insulin signalling, DNA repair | Impaired methylation, immune deficiency, blood sugar dysregulation, reduced wound healing |
| Cobalt | Vitamin B12 core element — cobalamin synthesis in gut bacteria | Functional B12 deficiency; impaired methylation cycle at MTR enzyme |
| Iron | Haemoglobin, cytochrome P450 enzymes (liver detoxification), ribonucleotide reductase (DNA synthesis) | Anaemia, impaired detoxification capacity, reduced cellular energy production |
| Calcium | Neuronal signalling, muscle contraction, enzyme activation, bone mineralisation | Neuromuscular dysfunction, impaired cellular signalling cascades |
The connection to folate metabolism deserves particular attention given the folic acid fortification context. MTHFR — the enzyme that converts folate to its active form — requires both zinc and riboflavin as cofactors. Manganese is a cofactor in the broader methylation cycle. Cobalt depletion impairs gut bacterial synthesis of B12 — the partner nutrient that makes remethylation of homocysteine possible. A compound that systematically depletes zinc, manganese, and cobalt is a compound that impairs folate and B12 metabolism even before MTHFR genetic variants are considered.
This is the layered problem the folic acid fortification policy has not addressed: the crop being fortified is grown using a compound that depletes the mineral cofactors needed to convert the synthetic folic acid being added to it. The intervention addresses the symptom of a system problem while the system problem continues to operate — and is in fact intensifying as glyphosate use continues to increase.
The evidence on hormone disruption —
what is established, what is accumulating, what is contested.
This is where the science is most actively contested, and where intellectual honesty requires careful calibration. The glyphosate-endocrine disruption literature is large, methodologically heterogeneous, and politically charged. Some studies show effects at very low doses in cell culture and animal models. Others find no effects at regulatory exposure levels in more controlled conditions. The picture is not settled, and claiming certainty in either direction would be inaccurate.
What can be said with reasonable confidence, sorted by evidence quality:
The Roundup formulation problem
Regulatory safety data is generated for glyphosate as an isolated compound. Roundup — the commercial formulation applied to crops — contains glyphosate plus surfactants (including polyethoxylated tallow amine, or POEA, in older formulations) that dramatically increase cellular penetration. Studies comparing glyphosate alone to Roundup formulation consistently find greater toxicity from the formulation. The regulatory framework assesses the active ingredient; farmers apply, and food contains residues of, the formulation. This gap has been acknowledged in the scientific literature and consistently unaddressed in the regulatory process.
What UK monitoring data shows —
and what it does not measure.
The UK Health and Safety Executive and the Food Standards Agency publish annual pesticide residue monitoring data. Glyphosate residues are detected regularly in UK food, with wheat and oats consistently among the highest-residue crops. This is not surprising — pre-harvest desiccation (spraying crops with glyphosate shortly before harvest to dry them uniformly and advance the harvest date) deposits glyphosate directly onto the grain, which is then milled into flour with minimal opportunity for residue reduction.
The monitoring data reports residue levels as percentages of the Maximum Residue Level (MRL) — the regulatory threshold. Most samples fall below MRL. This is typically interpreted as reassuring. Several caveats are worth noting:
- MRLs are not toxicological thresholds. They are administrative limits set based on what good agricultural practice produces — the level at which properly applied glyphosate should leave. They are not derived from studies of effects at those specific exposure levels in humans over a lifetime.
- Cumulative exposure is not monitored. A person eating wheat bread, oat porridge, and beer in the same day is receiving glyphosate residues from multiple sources simultaneously. Monitoring reports individual food residues; dietary exposure modelling is less comprehensive and rarely accounts for the full dietary pattern of high-grain consumers.
- Combination effects with other residues are not assessed. Glyphosate rarely arrives alone. Pesticide cocktails in real food samples have complex interaction effects that single-compound safety assessments cannot predict.
- Glyphosate metabolites are not consistently monitored. AMPA (aminomethylphosphonic acid), the primary environmental degradation product of glyphosate, has its own biological activity and is present alongside parent glyphosate in many samples. Its health effects have been assessed less thoroughly than glyphosate itself.
Practical steps — informed, not paralysed.
The honest position is that dietary glyphosate exposure at UK food residue levels has not been proven to cause specific harm in healthy humans — and that the studies needed to make that determination with confidence either have not been done or have not been funded by parties without a stake in the outcome. This is not a reason for panic. It is a reason for informed precaution and, where it matters most, for understanding your own biology.
Reduce exposure where practical
Choosing certified organic grain products — bread, oats, pasta — substantially reduces glyphosate exposure from the highest-residue food categories. Organic certification prohibits glyphosate use both as a herbicide and as a pre-harvest desiccant. The price premium is real; the decision is individual. Washing fruit and vegetables removes surface residues but does not address systemic residues in the plant tissue itself.
Support the mineral cofactors glyphosate depletes
Zinc, manganese, and magnesium adequacy are testable and supplementable at low risk. Given the mechanism of chelation and the documented depletion of these minerals in glyphosate-exposed soil (and potentially gut lumen), ensuring dietary and supplemental adequacy of these cofactors is a reasonable precautionary response regardless of where you sit on the evidence. Food sources: zinc from red meat, seeds, oysters; manganese from nuts, wholegrains, leafy greens; magnesium from dark leafy greens, dark chocolate, legumes.
Support gut microbiome resilience
The microbiome disruption mechanism is perhaps the most clinically actionable — because the microbiome responds to intervention more rapidly than any other system. Dietary diversity (30+ plant species per week), fermented foods (kefir, sauerkraut, kimchi), prebiotic fibre (inulin, resistant starch), and targeted probiotic support where GI-MAP testing indicates specific depletions all counteract the selective pressure that antibiotic-like compounds apply. This is not glyphosate-specific — it is good microbiome practice that becomes more relevant under chronic low-level antimicrobial exposure.
Consider testing if symptoms suggest mineral or microbiome impact
The OAT (Organic Acids Test) provides functional markers of mitochondrial function, B vitamin status, oxidative stress, and gut dysbiosis patterns. The GI-MAP provides direct quantitative analysis of microbiome composition including keystone species like Akkermansia and Faecalibacterium prausnitzii. Blood chemistry can assess zinc, ferritin, and full blood count for signs of mineral depletion patterns. None of these tests will tell you whether glyphosate specifically is the cause of any finding — but they tell you whether the systems glyphosate most plausibly affects are functioning normally, which is actionable regardless of aetiology.
The OAT also has a direct glyphosate measurement available as an add-on — a urine glyphosate marker that gives an actual quantified number rather than inference from downstream effects. The add-on costs approximately £95 on top of the standard OAT panel. For anyone with significant dietary exposure concerns, or where clinical findings suggest unexplained mineral depletion or dysbiosis that other factors don't fully explain, a direct measurement removes the guesswork entirely.
9.55 — when the result
goes off the right edge of the chart.
The following result came from an OAT glyphosate add-on run through Great Plains Laboratory on a clinical client. It is shared anonymised, with the individual's knowledge, because it illustrates a point that words alone do not convey as effectively.
The bar filled the entire reference range and extended beyond it. The 95th percentile is not a clean baseline — it represents the top of what is considered normal in a population with background glyphosate exposure from food. A result of 9.55 sits in a distribution that barely exists in the reference population.
The clinical context for this result matters. The individual in question was doing many things that should have reduced glyphosate exposure — organic food where possible, home-cooked meals, no obvious occupational exposure. They were not a farmer or agricultural worker. They were not living near intensive arable land. They were a reasonably health-conscious person living a fairly typical life, eating food from a standard UK food supply with some organic choices mixed in.
This is the point that individual precautionary behaviour runs into its structural limits. You cannot organic-food your way to zero exposure when glyphosate is in the water table, in the air particulate matter downwind of treated fields, in the non-organic components of processed foods that contain both organic and conventional ingredients, and in the gut of animals whose meat you eat even if the meat itself tests below detection. You can reduce the load. You cannot eliminate it. And until you measure it, you do not know where you actually are.
I have seen results like this — results that sit at multiples of the 95th percentile — in clients who would have told you with confidence that their diet was clean. The measurement changes the conversation from assumption to evidence. Which is, of course, the point of functional testing.
The AMPA ratio — what the metabolite adds
The OAT glyphosate add-on measures both glyphosate and AMPA — aminomethylphosphonic acid, the primary metabolic breakdown product. The ratio between them matters clinically. High glyphosate with low AMPA suggests recent or ongoing exposure the body hasn't had time to process — the input is still coming in. High AMPA relative to glyphosate suggests you're processing existing exposure but carrying a significant metabolic burden. High levels of both — as in the result above — indicates sustained exposure with detoxification pathways actively engaged and potentially under strain. AMPA itself has biological activity, disrupting cellular energy metabolism and in some cell lines showing greater toxicity than glyphosate itself. A test measuring glyphosate without AMPA gives you half the picture.
Who specifically should consider the add-on
Not everyone needs it. The direct glyphosate marker is worth ordering when the clinical picture suggests it will change what you do with the result. Specific indications: persistent dysbiosis that doesn't resolve despite gut work — if Lactobacillus and Bifidobacterium stay depressed after a full gut protocol, an ongoing hostile environment is worth ruling out; elevated Clostridia markers on the OAT (particularly HPHPA) that gut work isn't shifting; any occupational exposure to herbicides, groundskeeping, farming, or horticulture — where exposure is categorically higher than dietary; heavy conventional grain consumption (daily bread, pasta, oats, beer) combined with gut or inflammatory findings; and in children with dysbiosis-associated neurodevelopmental presentations where standard gut work isn't resolving the microbiome picture.
Current cost and test name
The glyphosate add-on is available through Great Plains Laboratory (GPL) as part of the GPL-TOX profile, or as a standalone urine glyphosate marker. Current cost is approximately £95–128 as an add-on to the standard OAT, depending on the panel configuration. It measures both glyphosate and AMPA in first-morning urine — the same collection as the standard OAT, so no additional collection is required.
The political ecology of this conversation
Glyphosate's regulatory status is one of the most contested questions in food safety science — not primarily because the science is uniquely ambiguous, but because the financial stakes are enormous. Bayer (which acquired Monsanto in 2018, inheriting approximately $10 billion in legal liability from glyphosate litigation) has a profound interest in maintaining the regulatory framework that approved it. The research institutions, regulatory agencies, and academic departments that have built relationships with agrochemical industry funding have structural incentives toward conclusions that do not disrupt the existing framework.
This does not make all pro-glyphosate research wrong. It means the precautionary principle — applying caution proportional to the potential harm before proof of harm is established at a standard the affected industry controls — applies here more than usually.
What this means for anyone
doing functional testing.
When I see a GI-MAP result with depleted Akkermansia and Faecalibacterium, elevated opportunistic pathogens, and a pattern suggesting chronic low-grade dysbiosis in a patient who eats a fairly typical UK diet, glyphosate exposure is one of several factors I consider. Not as a diagnosis — it cannot be diagnosed from a stool test — but as a plausible contributing pressure on a microbiome that is clearly under load.
When I see an OAT result showing elevated oxidative stress markers, impaired mitochondrial function, and low functional B vitamin status alongside a blood chemistry showing low-normal zinc and manganese, mineral chelation from dietary exposure is part of the clinical picture — alongside dietary inadequacy, gut absorption issues, and genetic factors.
The clinical question is never "did glyphosate do this?" The clinical question is "what systems are not functioning optimally, what is contributing to that, and what can we address?" Glyphosate exposure is a modifiable contributing factor for many people — not because the science is settled, but because reducing exposure and supporting the systems it most plausibly affects carries essentially no downside and potentially meaningful upside.
The next post in this series covers Bovaer — the methane inhibitor now approved for use in UK dairy cattle feed, what it is, how it works in the rumen, and what the residue and consent questions look like for dairy consumers.
If you suspect your gut or mineral status
is under pressure — test it.
The GI-MAP gives a direct quantitative picture of your microbiome, including the keystone species most affected by antibiotic-like compounds. The OAT adds functional B vitamin and mineral status markers. A 30-minute call costs nothing and clarifies which test is the right starting point for your picture.
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