Another peer-reviewed study has linked glyphosate to cancer. And almost on cue, Bayer has dismissed it with a familiar refrain: “serious methodological flaws.”
This time, it’s a multi-year toxicology study by the independent Ramazzini Institute and academic partners. Researchers found that rats exposed to glyphosate—or glyphosate-based herbicides—developed tumors in up to 14 organs. Some of these tumors appeared at the lowest tested dose, below levels regulators currently deem “safe.”
Bayer didn’t dispute the outcome as much as the process. Their rebuttal didn’t attempt to refute the data point by point. Instead, it attacked the credibility of the study itself.
And that’s what we need to talk about.
Bayer’s Well-Worn Script
If you’ve followed glyphosate for more than five minutes, you’ve heard this line before:
“This study has serious methodological flaws.”
It’s Bayer’s go-to strategy. Before Bayer, it was Monsanto’s.
When the World Health Organization’s International Agency for Research on Cancer (IARC) classified glyphosate as “probably carcinogenic to humans” in 2015, Monsanto launched a global PR campaign to discredit the panel. Internal documents later revealed they had planned this attack in advance—before the findings were even announced.
Since then, nearly every independent study that challenges glyphosate’s safety has been met with the same response: “bad methodology,” “non-standard protocols,” “conflicts of interest,” or “non-regulatory quality.”
And yet, when industry submits its own safety studies to regulators, those are rarely challenged with the same intensity. Even when they’re unpublished. Even when the data isn’t available for public scrutiny.
It’s a double standard dressed up as scientific rigor.
Who Conducted the Study—and Why That Matters
The latest study comes from the Ramazzini Institute, an Italian-based nonprofit with a long history of researching environmental and occupational carcinogens. Ramazzini is controversial—but not necessarily for the reasons Bayer suggests.
Their sin? Running studies that last longer than industry-funded ones and that sometimes find harms where others don’t.
Regulators like the EPA and EFSA have criticized Ramazzini’s work in the past, mainly on transparency and protocol grounds. But critics argue that this pushback often masks a deeper issue: independent research that challenges industry narratives is treated as suspect by default.
Shouldn’t we be more cautious of the studies submitted by the manufacturers of the chemical in question, not less?
What Regulators Say vs What Scientists Study
Much of the glyphosate debate boils down to how different institutions assess risk.
- The IARC looks at hazard: whether a substance can cause harm.
- Agencies like the EPA and EFSA look at risk: whether that harm is likely at expected exposure levels.
This difference may seem academic—but it has real-world consequences. Most regulators don’t conduct their own toxicological studies. Instead, they review the studies provided—often by the same companies selling the product.
This creates a strange situation where independent research is considered “non-regulatory quality,” while confidential, unpublished industry data gets to shape global policy.
Why This Matters in New Zealand
New Zealand is currently considering whether to raise allowable glyphosate residue levels (MRLs) on certain food crops—at a time when new research is pointing in the opposite direction.
Studies like the one just published raise valid questions about long-term, low-dose exposure—especially when exposure begins early in life. Shouldn’t those concerns be taken seriously before expanding our tolerance levels?
If every independent study is waved away with the same line—“flawed methodology”—then what exactly would it take for the system to pause, reconsider, or tighten safeguards?
Or are we expected to believe that no independent science, no matter how well-designed, will ever measure up to what industry says is safe?
Methodology Can Always Be Debated
That’s how science works.
But when every inconvenient study is reflexively dismissed by the chemical’s manufacturer using the same predictable script, we have to ask ourselves: is this science—or strategy?
Behind every MRL increase, every regulatory decision, every chemical approval, there are real people—eating, breathing, and living with the consequences.
We’re not anti-science. We’re pro-questioning. And we think New Zealand deserves better than a system where the loudest voice in the room belongs to the company with the most to lose.
Shouldn’t precaution come before profit—especially when lives are on the line?
Resources & References
Want to see how deep the story goes?
These sources offer a closer look at the study in question, Bayer’s response, and the wider context that’s been shaping the glyphosate debate for years. If you’re wondering whether this is about science, strategy—or something in between—these are good places to start.
AgFunder News – Bayer Responds to New Glyphosate Study
A recent industry-focused article summarizing Bayer’s official response to the Ramazzini Institute’s long-term glyphosate study, including key rebuttal points.
Environmental Health (June 2025) – Long-term Effects of Glyphosate Exposure in Rats
The peer-reviewed study at the center of the current debate, examining cancer incidence in rats exposed to glyphosate and glyphosate-based herbicides over two years.
WHO IARC – Glyphosate Monograph
The 2015 IARC classification that labelled glyphosate “probably carcinogenic to humans,” sparking global regulatory and legal controversy.
US Right to Know – Monsanto Papers
A searchable archive of internal Monsanto documents released through litigation, revealing strategies used to discredit independent scientists and manage public opinion.
Further Reading:
Whitewash: The Story of a Weed Killer, Cancer, and the Corruption of Science
Author: Carey Gillam
Written by an award-winning investigative journalist, Whitewash pulls back the curtain on Monsanto’s long-running campaign to protect glyphosate at all costs—through lobbying, ghostwriting, and attacks on independent scientists. It’s one of the most comprehensive deep dives into how the “flawed methodology” narrative has been used strategically for decades.
Toxic Legacy: [Our review]
Toxic Exposure: The True Story Behind the Monsanto Trials and the Search for Justice
Author: Chadi Nabhan, MD
Written by a physician who served as a key expert witness in the first Roundup-cancer trial, this book offers an insider’s view of the courtroom, the scientific evidence, and the human cost of corporate denial. A compelling complement to the science, it reveals what’s at stake when “serious methodological flaws” become a legal defense strategy.
Whitewash [Our review]
Because context matters.
When corporations cry “flawed science,” and regulators defer to industry data, it’s up to all of us to follow the trail. Read. Compare. Question. Decide.
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