- A 2000 study asserting that glyphosate — the active ingredient in Roundup — does not cause cancer has been officially retracted due to “serious ethical concerns” related to undisclosed connections with Monsanto.
- The investigation found evidence that Monsanto employees helped draft the paper and likely paid the authors, raising questions about research integrity and transparency.
- New independent studies published in 2025 link glyphosate exposure to increased cancer risk, providing stronger evidence of the herbicide’s carcinogenic potential.
A critical part of reading and understanding research is assessing the sources of funding for studies. Usually, it’s easy to find right at the bottom of the study’s disclosure statements. It often notes whether the funding is from a university or a nonprofit, or whether the researchers were funded by a company to specifically study a product. It’s a foundation of research ethics. But, like all industries, science can have some bad apples, too. And that appears to be the case for one rather important scientific article published at the turn of the century.
In 2000, researchers published findings from a study on glyphosate, the active ingredient used in Roundup, which is sprayed on crops worldwide. At the time, the published study reported no evidence that it caused cancer. However, the journal that published it, Regulatory Toxicology and Pharmacology, is retracting the study over what it calls “serious ethical concerns.”
“Concerns were raised regarding the authorship of this paper, validity of the research findings in the context of misrepresentation of the contributions by the authors and the study sponsor, and potential conflicts of interest of the authors,” the journal’s co-editor-in-chief, Professor Martin van den Berg, Ph.D., wrote in the retraction. “I, the handling (co)Editor-in-Chief of Regulatory Toxicology and Pharmacology, reached out to the sole surviving author, Gary M. Williams, and sought an explanation for the various concerns which have been listed in detail below. We did not receive any response from Prof. Williams. Hence, this article is formally retracted from the journal.”
The decision, van den Berg added, was made after a 2017 lawsuit, filed by people who claimed to have developed non-Hodgkin lymphoma — a blood cancer that affects lymphocytes — after being exposed to the herbicide, uncovered emails between Monsanto executives and the authors suggesting that Monsanto employees contributed to writing the paper while ensuring that these employees were never named.
“This lack of transparency raises serious ethical concerns regarding the independence and accountability of the authors of this article and the academic integrity of the carcinogenicity studies presented,” van den Berg said.
Van den Berg stated that the emails also indicated that Monsanto likely paid the authors for their work, a fact not disclosed in the final study. “The potential financial compensation raises significant ethical concerns and calls into question the apparent academic objectivity of the authors in this publication, which concerns and questions have not been answered,” Van den Berg explained.
Because of this potential relationship with Monsanto, he added, “It is unclear how much of the conclusions of the authors were influenced by external contributions of Monsanto without proper acknowledgments.”
The reason this ever came to light, Science explained, is all thanks to two other researchers who filed the initial retraction request, including Naomi Oreskes, a historian of science at Harvard University, and her then-postdoctoral researcher, Alexander Kaurov. “My worry is that people will keep citing it,” Oreskes said.
New research is already taking the flawed study’s place. In 2025, Food & Wine reported on two new studies, one published in Scientific Reports that offered fresh insight into how glyphosate could bind to several enzymes and a protein called plasminogen, which are key to the human body’s ability to remodel tissue. When these break down, it often leads to kidney disease and cancer. The other, published in the journal Environmental Health, found that rats exposed to glyphosate and glyphosate-based herbicides had higher rates of cancer, including increased occurrences of leukemia, as well as skin, liver, thyroid, and bone cancers.
“Our study provides solid and independent scientific evidence of the carcinogenicity of glyphosate and glyphosate-based herbicides,” Daniele Mandrioli, the director of the institute’s Cesare Maltoni Cancer Research Center, said in a statement at the time.
Why funding disclosures matter in scientific research
In scientific publishing, researchers must disclose who funded their work and whether any outside organization played a role in shaping the study. These disclosures don’t automatically invalidate research — but they provide readers, regulators, and other scientists with critical context for interpreting the findings.
When funding sources or contributions are concealed, it becomes difficult to assess whether a study’s conclusions were influenced by financial or corporate interests. That lack of transparency can undermine trust not only in a single paper but also in the scientific process itself — especially when research is used to guide public health policy and regulatory decisions.
Kaurov also told Science that additional retractions may be forthcoming, noting that he and Oreskes submitted a retraction request to Critical Reviews in Toxicology for a 2013 paper that fully disclosed Monsanto’s role. He added, “It’s not the end of the story.”
As van den Berg concluded in the retraction, this 2000 paper had a “significant impact on regulatory decision-making regarding glyphosate and Roundup for decades. Given its status as a cornerstone in the assessment of glyphosate’s safety, it is imperative that the integrity of this review article and its conclusions are not compromised. The concerns specified here necessitate this retraction to preserve the scientific integrity of the journal.”
