Study Often Used to Cite Roundup’s Safety Retracted

A 25-year-old academic study that laid the foundation for the supposed safety of the herbicide glyphosate has been retracted by the journal that originally published it.

The journal “Regulatory Toxicology and Pharmacology” published a 48page groundbreaking study on glyphosate in its April 2000 issue that concluded, “Roundup herbicide does not pose a health risk to humans.” Glyphosate is the active ingredient in the popular herbicide known as Roundup.

The journal issued a retraction notice in its December 2025 issue disputing the claims made in the 2000 paper. The retraction came at the request of the journal’s Co-Editor-in-Chief, Prof. Martin van den Berg, Ph.D. The retraction alleges that glyphosate’s manufacturer, Monsanto, paid the authors to publish the study, and its findings were influenced by Monsanto employees. Monsanto is now owned by the German company Bayer.

“The paper had a significant impact on regulatory decision-making regarding glyphosate and Roundup for decades,” the retraction notice stated. “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.”

Van den Berg outlined several “critical issues that are considered to undermine the academic integrity of this article and its conclusions.”

The retraction notice said the article’s three authors, Gary M. Williams, Robert Kroes, and Ian C. Munro, may not have been solely responsible for the content of the study. Correspondence that came out in recent litigation suggests that Monsanto employees may have contributed to the article without proper acknowledgement.

“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,” the journal said.

“The failure to disclose the involvement of Monsanto personnel in the writing process compromises the academic independence of the presented findings and conclusions drawn in the article regarding carcinogenicity,” the journal went on to say. The correspondence between Monsanto and the article’s authors indicates that Monsanto paid the authors for their work.

“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,” the journal said.

Most alarming are the new revelations about the article’s conclusions. The authors’ main point was that glyphosate does not cause cancer. But the retraction notice says they ignored several other studies that reached other conclusions.

“The authors did not include multiple other long-term chronic toxicity and carcinogenicity studies, that were already done at the time of writing their review in 1999,” the retraction states. “In their article the authors state that they are aware of other studies, that were unpublished and not available. However, the authors do not specify to what extent they tried to incorporate the findings of these (unpublished) studies. The reasons for this remain undisclosed but bring into question the broader objectivity of the conclusions presented.”

The Center for Biological Diversity had this to say about the retraction: “The article has been cited extensively by regulatory agencies around the world, including the U.S. Environmental Protection Agency, as evidence that glyphosate poses no cancer risk to humans. The paper is in the top 0.1% of cited articles on glyphosate in the scientific literature, meaning it is more highly cited than 99.9% of articles written on the chemical.”

In recent years, Bayer has faced thousands of lawsuits claiming they failed to warn the public about the risks associated with glyphosate. The study’s retraction comes just as the Trump Administration filed a brief in the U.S. Supreme Court this month asking the justices to curb the lawsuits, which would protect Bayer from potentially billions of dollars in damages.

This move seems at odds with the administration’s Make America Healthy Again initiative, which has resulted in some food manufacturers removing artificial dyes and other chemical ingredients from their products over concerns about safety. Ironically, no one would know about Monsanto’s influence on the glyphosate cancer article without these lawsuits.

In the 25 years since the study came out, glyphosate has become one of the most common herbicides used across the globe. Homeowners spray it along curbs and sidewalks to control weeds. Farmers spray it on wheat just before harvest to dessicate the stalks and make it easier to collect grain. They spray it on geneticallyengineered corn to control weeds. The Texas Department of Transportation, in its “Herbicide Operations” manual, proscribes its use for “chemical mowing” and “chemical pruning” along roadsides.

Try as you may, you can’t escape glyphosate. It’s everywhere. And now, it appears, the foundation of its supposed safety was bought and paid for by the people who sell it.