We’re often told that glyphosate – when used “properly” – poses little to no risk.
But a major scientific review published in Frontiers in Toxicology in late 2024 makes it hard to accept that reassurance at face value.
This wasn’t a single study tucked away in a lab report. It was a broad analysis of decades of evidence on glyphosate and its breakdown products—covering cancer risks, DNA damage, hormone disruption, and effects on reproduction. In other words, the kind of sweeping overview regulators claim to rely on, yet somehow manage to overlook when drafting policy.
If glyphosate quietly infiltrates our food, waterways, and bodies—and regulators still insist it’s “safe”—we’re not just talking about a policy oversight; we’re talking about a public health blind spot.
In our recent article, No One in Good Conscience Can Claim That Glyphosate Is Compatible with Human Health, we pointed to studies from June and August 2025 that raise fresh alarms. This 2024 review adds important weight to that picture, showing that concern about glyphosate is not new, but has been building for years.
So, what exactly did the review uncover—and why should New Zealanders be paying attention now?
Why This Study Matters
When regulators defend glyphosate, they often lean on narrow, selective studies—usually short-term toxicology tests on animals, sometimes focused on just one outcome like acute poisoning. What makes this Frontiers in Toxicology review so important is its scope.
Instead of looking at a single lab experiment or one country’s dataset, the authors pulled together evidence from across the scientific landscape. They examined glyphosate itself, its main metabolite AMPA, and the commercial formulations we actually use in the real world, such as Roundup®.
Crucially, they didn’t just focus on cancer (the one risk most people have heard of). They also looked at reproductive health, DNA damage, hormone disruption, and population monitoring data that show glyphosate turning up in people’s urine, blood, and even breast milk.
This matters because it paints a much fuller—and frankly, much more troubling—picture than what we’re usually told. It reminds us that glyphosate isn’t just an “on the farm” issue. It’s an everyday exposure issue, and one that regulators consistently underestimate by looking at slices of the evidence rather than the whole body of work.
Key Findings from the Review
1. Carcinogenic and Mutagenic Potential
One of the most contested questions about glyphosate is whether it can cause cancer. The International Agency for Research on Cancer (IARC) said yes back in 2015, classifying glyphosate as a “probable human carcinogen.” The European Food Safety Authority (EFSA), however, came to the opposite conclusion in 2022, saying it was “unlikely” to cause cancer.
This review shows why that divide matters. It highlights studies that found DNA damage and oxidative stress linked to glyphosate exposure—biological red flags that can trigger cancer development. In other words, there’s scientific evidence of mutagenic potential, even if regulators prefer to downplay it.
2. Endocrine Disruption and Reproductive Effects
The review also looked beyond cancer. It found growing evidence that glyphosate can act as an endocrine disruptor, interfering with hormones in ways that ripple across the body. Some of the most concerning effects are in the reproductive system—reduced fertility, developmental issues, and possible impacts on offspring.
This is especially important because endocrine disruption doesn’t follow the “dose makes the poison” logic regulators love to repeat. Low, chronic exposures can sometimes do more harm than higher doses—yet regulatory testing rarely accounts for this.
3. Biomonitoring: Evidence of Widespread Exposure
Perhaps most eye-opening is the global evidence showing glyphosate isn’t just out in the fields—it’s inside us. Monitoring studies across different countries have found glyphosate and its breakdown product AMPA in urine, blood, and even breast milk. The levels may sound “low,” but the reality is that exposure is chronic, cumulative, and widespread.
If testing were carried out here in New Zealand, would the results look any different? The honest answer is: we don’t know—because our government hasn’t looked.
4. Contradictions and Gaps
The review also highlights the contradictions between different agencies. Some acknowledge red flags, while others wave them away. Add to this the fact that most toxicological studies are still carried out on male animals only, leaving big blind spots about potential impacts on women, children, and vulnerable groups.
And then there’s the missing research on low-dose, long-term exposure—the very scenario most of us are living with. Regulators continue to rely on outdated high-dose models, ignoring what real-world science is telling us.
Why It Matters in New Zealand
It’s easy to dismiss studies like this as “overseas science.” But this Frontiers in Toxicology review matters deeply here — especially when paired with the glaring gaps in our own systems.
1. Regulators Are Raising Limits While Ignoring Exposure
While scientists highlight risks like cancer, DNA damage, and hormone disruption, New Zealand’s Ministry for Primary Industries is proposing a massive 9,900% hike in acceptable glyphosate residue levels for wheat, barley, and oats—up from 0.1 mg/kg to 10 mg/kg. And shockingly, nearly a decade has passed since the last New Zealand-wide monitoring of food for glyphosate residues.
2. No Public Testing, No Data, No Accountability
New Zealand has virtually no accessible system for tracking glyphosate exposure in people. In our July 2025 article “No Testing. No Tracking. No Plans to Change That,” we revealed that the Ministry of Health confirmed there’s no public process or facility for glyphosate urine testing—and no plans to change that.
3. Even Private Testing Is Hard to Find
We also explored the structural barriers in “Want to Know Your Glyphosate Levels? Good Luck With That.” Even the Ministry couldn’t point us to a testing facility at first. Eventually, they referred us to a private clinic—House of Health—that sends samples overseas. Testing is possible, but expensive, inaccessible, and entirely outside public health infrastructure.
4. Independent Testing Is the Only Real Insight
Because the government won’t measure exposure, we’re stepping in. No More Glyphosate NZ has launched independent testing of honey, Weet‑Bix, breakfast cereals, and bread. These tests show glyphosate residues in everyday foods—and they’re the only data points we have.
Why This Matters:
If regulators won’t measure glyphosate—its presence in our bodies, our food, or our environment—then we remain blind. That’s not oversight; it’s willful omission. The Frontiers review shows that long-term, low-level exposure does matter. What the government fails to measure could be the difference between claiming safety and actually knowing it.
The Bigger Picture
The story of glyphosate is not just about one weedkiller. It’s about how we as a society handle chemicals that quietly weave their way into our food, water, and bodies.
Regulators often reassure us by pointing to “maximum safe levels,” but that reassurance rests on shaky ground. Those limits are set for individual chemicals in isolation, based on short-term studies, and usually tested at higher doses than people are actually exposed to.
What they don’t account for is the cumulative impact of multiple low-level exposures over a lifetime — or how chemicals may interact with each other in unpredictable ways.
Glyphosate is a perfect example. For years, it has been framed as a precision tool that targets plants, not people. Yet study after study has chipped away at that narrative, showing potential for cancer, hormone disruption, oxidative stress, and DNA damage. Add to this the fact that we’re rarely exposed to glyphosate alone — most of us encounter it in formulated products like Roundup®, which can be even more toxic than glyphosate on its own.
This is the “death by a thousand cuts” problem. A single trace exposure might not cause immediate harm. But stack that on top of residues in food, traces in water, occupational exposure, and other pesticides in the mix, and the margin of safety regulators like to promise starts looking more like wishful thinking.
The bigger picture isn’t just about glyphosate. It’s about a system that consistently underestimates risk, overlooks gaps, and leaves the public to carry the burden. Until we start treating chemicals with the same precaution we expect in other areas of public safety, we’ll continue to trade long-term health for short-term convenience.
This is where a Critical Mindshift is needed. Too often, we take regulatory assurances at face value — assuming that “safe” really means safe, or that someone else has already asked the hard questions on our behalf. But when it comes to chemicals like glyphosate, those assumptions can be dangerous. Real critical thinking starts with asking: who sets the limits, whose interests are protected, and what evidence gets left out?
Where This Leaves Us
The 2024 Frontiers in Toxicology review is a reminder that glyphosate isn’t just a farming tool — it’s a public health question that refuses to go away. Cancer risks, hormone disruption, DNA damage, oxidative stress — these aren’t fringe claims. They’re patterns that emerge again and again when scientists look at the data.
And yet here in New Zealand, instead of exercising caution, regulators are pushing to loosen protections. They’re raising residue limits rather than tightening them, ignoring biomonitoring, and leaving citizens in the dark about their actual exposure. That’s not precaution — it’s gambling with public health.
Independent testing has already shown glyphosate residues in honey, Weet-Bix, and breakfast cereals. These results, funded by everyday New Zealanders, prove what the government isn’t willing to measure: glyphosate is in our food, in our daily lives, and almost certainly in our bodies.
The question is no longer whether glyphosate is safe “within limits.” The question is why our institutions continue to act as if those limits mean anything at all.
That’s why we’ll keep testing, keep asking the hard questions, and keep pushing for transparency. Because until glyphosate is treated with the same seriousness as other public health threats, New Zealanders will remain unprotected — and that’s something no one in good conscience should accept.
If you value the work we’re doing, there are two simple ways to help. Follow No More Glyphosate NZ on Facebook and X.com to stay connected and share our message. And if you’re able, support our independent testing with a donation — every contribution helps us uncover the truth regulators won’t.
Together, we can keep the pressure on, keep testing, and keep demanding a safer future for all New Zealanders.
Resources & References
When it comes to glyphosate, the problem isn’t a lack of science — it’s what gets ignored. Regulators cherry-pick narrow studies to justify business as usual, while broader reviews and independent testing tell a very different story. Below is a collection of resources that shine a light on the evidence too often left out of the conversation.
Peer-Reviewed Studies & Reviews
Frontiers in Toxicology (2024):
Overview of human health effects related to glyphosate exposure
Comprehensive review examining carcinogenicity, mutagenicity, endocrine disruption, and biomonitoring evidence.
IARC Monographs (2015):
Glyphosate Classified as Probably Carcinogenic (Group 2A)
Landmark classification that first raised global concern about glyphosate’s carcinogenic potential.
EFSA (2022):
Peer review of the pesticide risk assessment of glyphosate
European Food Safety Authority concluded glyphosate was “unlikely” to pose a carcinogenic hazard, in sharp contrast to IARC.
No More Glyphosate NZ Articles
No One in Good Conscience Can Claim That Glyphosate Is Compatible With Human Health
Our August 2025 article examining why glyphosate’s safety narrative no longer holds up against mounting scientific evidence.
No Testing. No Tracking. No Plans to Change That.
Reveals that New Zealand has no public process for testing glyphosate exposure in people — and no plans to implement one.
Want to Know Your Glyphosate Levels? Good Luck With That.
Examines the barriers to glyphosate urine testing in New Zealand, including reliance on costly overseas labs.
Glyphosate in NZ Honey: Test Results
Our independent testing uncovered glyphosate residues in honey sold on New Zealand shelves.
Weet-Bix Glyphosate Test Results
Crowdfunded testing found glyphosate in New Zealand’s most iconic breakfast cereal.
Glyphosate in Waterways: A Contamination Crisis
Explores how glyphosate residues move through the environment, threatening rivers, lakes, and ecosystems.
Why Raising MRLs Threatens Public Health
Our analysis of MPI’s proposal to increase glyphosate residue limits on staple crops by nearly 10,000%.
These resources reveal a consistent pattern: evidence of harm exists, yet regulators continue to downplay or dismiss it. By connecting international science with local realities, we can see clearly that glyphosate is not just a farming issue — it’s a public health issue.
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