Glyphosate
Glyphosate is the world's most-used weedkiller, and the place where cancer regulators most openly disagree. Heavy, mostly occupational exposure is linked to a higher risk of non-Hodgkin lymphoma in two meta-analyses, but the studies are few and observational, Europe's food-safety agency found no critical concern, and for an ordinary diet switching to organic food barely changes how much reaches you.
Don't reorganise your shopping around glyphosate: in the one randomised test, an organic diet barely moved urine levels. The lymphoma signal comes from heavy, mostly farm-work exposure, so that is where caution belongs.
The lymphoma signal: real enough to take seriously, thin enough to doubt
The International Agency for Research on Cancer (IARC), the World Health Organization's cancer agency, rates glyphosate "probably carcinogenic to humans" (Group 2A), driven by non-Hodgkin lymphoma, a cancer of the white blood cells.
A 2019 meta-analysis found about 41% higher lymphoma risk among the most heavily exposed, mostly agricultural workers, where recall and healthy-worker biases apply.[1] The range around that figure was wide, it rested on only six studies, and the largest of them — the prospective US Agricultural Health Study, which followed farmers forward rather than asking cancer patients to recall past use — was itself null.
An independent 2026 meta-analysis of ten primary datasets, with no external funding and formal grading of certainty, broadly replicated the signal. The highest exposure categories carried roughly 28–45% higher odds of lymphoma depending on the statistical model, while simply ever having been exposed showed only a modest association. The authors rated overall certainty as moderate.[2]
Regulators split
The European Food Safety Authority reviewed more than 2,400 studies and in July 2023 identified no critical areas of concern,[3] and the EU renewed glyphosate's approval to 2033.[4]
The US position is unsettled. The US Environmental Protection Agency (EPA) concluded in 2020 that glyphosate is unlikely to be a human carcinogen, but a federal appeals court vacated that human-health finding in 2022, the agency withdrew the decision, and the reassessment it was ordered to redo is still not finished.[5]
What diet changes do to your levels
Very little, on the best evidence. In a two-week randomised crossover trial in 39 pregnant participants, with samples analysed at a US Centers for Disease Control and Prevention laboratory, median urinary glyphosate barely moved on an organic diet, from 0.19 to 0.16 µg/L, and did not fall at all in people living near farmland.[6] An uncontrolled before-and-after switch in four families, run with an environmental campaign group, reported a fall of about 70%, but with no comparison group.[7]
Washing produce is worth doing for surface residues: a plain rinse removes roughly a third and a baking-soda soak about half. It does little for glyphosate, which is taken up into the plant tissue rather than sitting on the skin. Those washing figures come from authors at the Environmental Working Group, an advocacy organisation.[8]
What to do
- Don't pay a premium for organic on glyphosate grounds alone; the one randomised test found a barely measurable change.
- Rinse produce for surface residues in general, knowing it won't remove glyphosate.
- If you handle glyphosate heavily, at work or on a farm, the lymphoma evidence is about you; treat it as an occupational-health matter.
More on household chemical exposures is on Environmental toxins.
Further reading
- Zhang L et al. Exposure to glyphosate-based herbicides and risk for non-Hodgkin lymphoma: A meta-analysis and supporting evidence. Mutat Res Rev Mutat Res 2019.[9]
- Gagnier JJ, O'Connor JP. A Systematic Review and Meta-Analysis of Glyphosate-Based Herbicide Exposure and Risk of Non-Hodgkin Lymphoma. Int J Environ Res Public Health 2026.[10]
- Hyland C et al. Urinary Glyphosate Concentrations among Pregnant Participants in a Randomized, Crossover Trial of Organic and Conventional Diets. Environ Health Perspect 2023.[11]