Written by
Louise W Lu, PhD, MPH, BMLS
Written/Reviewed by
Alexandra V Goldberg, Registered Dietitian
Recently, the New Zealand government proposed a highly controversial food safety policy: to raise the maximum residue limits (MRLs) of glyphosate in crops such as grains and legumes by dozens of times.
This proposal has sparked widespread public concern, with more than three thousand submissions, while environmental groups and food safety organizations also expressed their worries.
At the same time, another policy — the “Genetic Technology Bill” — is also advancing, which may relax regulations on genetically modified (GM) and gene-edited crops. The overlap of the two policies has pushed “glyphosate” into the center of public debate.
So, what exactly is glyphosate? Does it really threaten health? Can residues be removed through washing or cooking? How can we reduce risks in daily life? And especially for children and pregnant women — how can they protect themselves?
In fact, glyphosate is not just a New Zealand issue. Some EU countries have announced plans to gradually ban it, while the U.S. and China still allow its use, though with different regulatory standards.
With these questions in mind, we have prepared “10 Questions & Answers on Glyphosate”, to help you clearly understand the real relationship between glyphosate and health.
📖 Click to Expand / Collapse Contents
Q1 What exactly is glyphosate? Is it safe?
Glyphosate is one of the most widely used herbicides in the world, commonly known by the brand name “Roundup”. It works by inhibiting a key enzyme in plants called EPSPS, blocking amino acid synthesis and thereby killing weeds. Due to its high efficiency and low cost, glyphosate is widely used in the cultivation of grains, legumes, and oil crops.
When it comes to safety, conclusions from different authorities are not entirely consistent:
- The International Agency for Research on Cancer (IARC, under WHO) classified glyphosate in 2015 as “probably carcinogenic to humans” (Group 2A).
- The U.S. Environmental Protection Agency (EPA) in its 2020 review stated that, under currently approved uses, glyphosate poses “no risk” to human health.
Overall, the scientific community remains divided. Glyphosate is neither “completely safe” nor “definitely carcinogenic.” The key lies in the dose and frequency of long-term exposure.
So, what counts as “long-term exposure”?
- European Union (EFSA): 0.5 mg/kg body weight/day
- WHO/FAO (JMPR): 0–1 mg/kg body weight/day
- US EPA: 1.75 mg/kg body weight/day
For example: An adult weighing 60 kg, under EU standards, would exceed the safety threshold if consuming more than 6 mg of glyphosate daily for 5–10 years; under U.S. EPA standards, the maximum allowable amount is nearly 105 mg per day. Such vast differences in standards are a key source of scientific controversy.
Q2 What are the residue limits of glyphosate in food?
Different countries and regions set very different Maximum Residue Limits (MRLs) for glyphosate in food.
European Union: The strictest standard, with typical limits in grains and legumes around 0.1–0.5 mg/kg, emphasizing “minimizing long-term exposure.”
United States: Much more lenient, with MRLs for crops such as soybeans and corn reaching up to 20–30 mg/kg, far higher than the EU.
China: Implements GB 2763-2021 “National Food Safety Standard – Maximum Residue Limits for Pesticides in Food”. For example:
- Tea: 1 mg/kg
- Corn: about 1 mg/kg (depending on category)
- Soybeans: lower than 20 mg/kg (different from Codex feed-use standards)
New Zealand: In 2024, a proposal was made to raise glyphosate MRLs for some crops, such as grains from 0.1 mg/kg up to 10 mg/kg, and dry peas up to 6 mg/kg — a move that has drawn significant public concern. [RNZ News]
In summary: The EU is the strictest, the US is the most lenient, while China and New Zealand fall somewhere in between. This explains why views on glyphosate safety vary so widely across countries.
Q3 What health effects can glyphosate have?
At first, glyphosate was promoted as “low toxicity and relatively safe for humans.” But more and more studies now suggest that if you’re exposed for a long time or at high doses, the health risks can’t be ignored.
Cancer risk:
The International Agency for Research on Cancer (IARC) under the WHO classified glyphosate in 2015 as “probably carcinogenic to humans” (Group 2A). Some studies have linked glyphosate exposure with a higher risk of non-Hodgkin lymphoma.
Hormonal and developmental effects:
Experiments suggest glyphosate may disrupt the endocrine system, potentially affecting reproductive health and fetal development. For example, research from the Ramazzini Institute showed that mice exposed to low doses of glyphosate-based herbicides from pregnancy through adulthood showed significant changes in hormone levels and development. [Study link]
Gut and immune system impacts:
Some studies indicate glyphosate can disrupt gut microbiota balance, weaken the gut barrier, and potentially trigger inflammation and immune dysfunction. [Systematic Review]
But here’s the catch: different agencies disagree. The U.S. EPA and the European Food Safety Authority (EFSA) both say that within approved usage limits, glyphosate is unlikely to pose a cancer risk to the public. That’s why the real debate centers on whether long-term, low-dose exposure is truly safe.
Q4 Can washing or cooking get rid of glyphosate?
Many people’s first thought is: “If I wash the food really well or cook it longer, won’t that solve the problem?” Unfortunately, glyphosate is a systemic herbicide, which means plants absorb it deep into their leaves, stems, roots, and even seeds. So while washing or peeling can remove a little residue on the surface, it can’t get rid of the glyphosate inside.
Washing:
Rinsing or soaking in baking soda solution can wash off some surface residues, but it has very limited effect on glyphosate. Studies show that results vary depending on the type of vegetable and pesticide. [Study example - MDPI]
Cooking:
Boiling, steaming, or frying can break down certain pesticides, but glyphosate stays quite stable under normal cooking temperatures. Even after long cooking, it doesn’t fully degrade. [EFSA Glyphosate Review]
Smarter strategies:
Instead of relying on washing or cooking, the better approach is to control exposure at the source — for example, choosing organic when possible, eating a varied diet, and avoiding over-reliance on high-risk crops.
Bottom line: Washing and cooking may reduce residues on the outside, but the real way to cut glyphosate exposure is through your food choices.
Q5 How can we reduce our exposure to glyphosate in daily life?
Glyphosate often shows up in grains, beans, and oilseed crops. The good news is, with a few smart choices, you can significantly cut down your intake.
Choose organic foods:
Organic farming bans glyphosate. Studies have shown that people on an organic diet tend to have much lower glyphosate levels in their bodies. [NIST: Lower glyphosate in organic oats] [Environmental Research: Organic diet intervention lowered urinary glyphosate]
Keep your diet varied:
Don’t rely on the same grain or bean every day. Mix it up! Variety helps reduce cumulative exposure.
Avoid high-risk crops:
Some crops (like wheat, oats, and dry peas) may be sprayed with glyphosate before harvest for “drying.” That often means higher residue levels (though studies are mixed). [NZ MPI Proposal: Raising glyphosate MRLs in wheat, oats, barley, peas] [UK AHDB: Pre-harvest glyphosate and residue management]
Watch your drinking water:
In farming areas, groundwater may be contaminated with glyphosate. Using certified filters (like activated carbon) can help cut exposure.
Check labels and policies:
Keep an eye on food safety standards and policy changes. For example, New Zealand recently debated raising the glyphosate residue limits for some crops, sparking strong public reaction. [RNZ News]
In short: With organic options + diet variety + choosing lower-risk crops + safe water, you can effectively lower your daily glyphosate exposure.
Q6 Can the body get rid of glyphosate on its own?
In simple terms, most glyphosate doesn’t stay in your body for long. Once it gets in, it’s mainly flushed out through urine, with a small amount through stool. Recent studies suggest its half-life in the body is just a few hours up to around 20–25 hours. That means within a day or two, levels in your body can drop noticeably. [Thailand Study, 2024]
How it’s processed:
Glyphosate is hardly broken down inside the body. It basically goes out the same way it came in—filtered by the kidneys and out through urine. So if your intake is occasional and low, the body can gradually clear it out.
How fast it leaves:
Some studies show glyphosate levels can drop significantly within about 20–25 hours. However, claims like “over 90% is gone within 3–5 days” don’t have strong scientific backing yet.
A special note:
With long-term, repeated low-level exposure, even though the body keeps excreting it, there may always be a small trace left. That’s one of the key reasons why scientists are still debating its health risks.
Bottom line: Yes, your body can get rid of glyphosate—but not in a way that guarantees it’s “completely gone.” What really matters is reducing everyday exposure so your body doesn’t carry that extra burden.
Q7 Are children and pregnant women at higher risk from glyphosate?
Yes, children and pregnant women are considered more sensitive groups. Due to developmental and metabolic characteristics, they are more vulnerable to the effects of glyphosate.
Children’s risk:
Children’s liver and kidney detoxification functions are not yet fully developed, and their lower body weight means that the same exposure results in a higher dose per kilogram of body weight. Some studies suggest that glyphosate exposure may be linked to attention and cognitive development issues in children, but the evidence remains preliminary and inconsistent across studies. [Systematic Review, Pre-/Postnatal Exposure]
Pregnancy risk:
Research on pregnancy exposure has shown that higher maternal urinary glyphosate levels are associated with lower fetal weight percentiles. For example, the study “Glyphosate exposure in early pregnancy and reduced fetal growth” found a negative correlation between maternal glyphosate levels in early pregnancy and birth weight percentiles. [Indiana Pregnancy Environmental Exposures Study]
Views of authorities:
EFSA and the U.S. EPA consider the risks controllable under “reasonable use,” but WHO and IARC emphasize adopting a stricter precautionary principle for vulnerable groups such as children and pregnant women.
In summary: Children and pregnant women are indeed more susceptible to glyphosate. It is recommended to choose organic foods whenever possible, avoid high-risk crops, and reduce long-term exposure.
Q8 Is the evidence on glyphosate and cancer consistent?
This is one of the most debated questions in the scientific community. Different institutions and studies have drawn very different conclusions.
Evidence supporting “possibly carcinogenic”:
The World Health Organization’s International Agency for Research on Cancer (IARC) classified glyphosate in 2015 as “probably carcinogenic to humans” (Group 2A). This was mainly based on epidemiological studies suggesting a link between glyphosate exposure and non-Hodgkin lymphoma.
Evidence supporting “risk is manageable”:
The US EPA and the European Food Safety Authority (EFSA) concluded that, when used according to regulations, glyphosate is unlikely to be carcinogenic. They emphasize that existing animal studies and human data are insufficient to confirm a cancer link.
Independent studies and legal cases:
Some independent research continues to point to potential cancer risks. In the US, courts and juries in California and other states have ruled that glyphosate-based products were linked to cancer, requiring manufacturers to pay compensation.
Summary: Does glyphosate cause cancer? The scientific community has not reached a consensus. The controversy centers on whether long-term, low-dose exposure is enough to increase cancer risk.
Q9 What is the link between glyphosate and genetically modified (GM) crops?
Glyphosate and GM crops are closely connected — almost like “twins.” Many common GM crops, such as soybeans, corn, and cotton, are designed to be resistant to glyphosate. This means farmers can spray large amounts of herbicide, weeds die, but the crops survive.
Why engineer crops this way?
For farmers, it’s a big win: less labor, lower costs, and higher yields. Today, more than 90% of GM soybeans worldwide are glyphosate-resistant varieties.
So what’s the problem?
Because the crops can tolerate glyphosate, spraying tends to be more frequent. The result? Higher glyphosate residues in these crops, plus the rise of “superweeds” that evolve resistance, making farmers depend on even more herbicides.
Should consumers worry?
In foods made from soybeans and corn, glyphosate residues are indeed more commonly detected. That’s why some countries have imposed strict limits, or even banned the cultivation of glyphosate-tolerant GM crops altogether.
In short: Glyphosate-tolerant GM crops are one of the main drivers behind the global surge in glyphosate use, and they’re also a key reason why consumers often question the safety of GM foods.
Q10 Are there safer alternatives to glyphosate?
The answer is: yes! In fact, farmers and researchers have been looking for ways to reduce reliance on glyphosate for years.
Mechanical methods:
Using tillers, mowers, or planting cover crops to suppress weeds. These methods take more effort but can significantly reduce pesticide use.
Biological control:
Taking advantage of natural enemies such as insects, fungi, or bacteria to fight weeds. Some soil microbes can even damage weed root systems directly.
New low-toxicity herbicides:
Scientists are working on herbicides that are less toxic and degrade more quickly, some derived from natural substances, which are considered more environmentally friendly.
Organic and ecological farming:
Practices like crop rotation, intercropping, and ecological design help reduce weed pressure. These methods not only lower pesticide use but also improve soil health.
In short: Glyphosate is not the only option. Alternatives may cost more or require extra labor, but for health and environmental reasons, more countries and farmers are moving toward sustainable solutions.
