A New Analysis Shows a ‘Compelling Link’ Between Roundup and Cancer

Monsanto has long denied a link between its globally-used weed killer, glyphosate, and cancers in humans, but a new meta-analysis finds a “compelling link” that could finally prompt the EPA to reevaluate its own classification of the ubiquitous herbicide.

The review, published this month in “Mutation Research/Reviews in Mutation Research“, looks at the broad spectrum herbicide and investigates studies that deal with high cumulative exposures. The University of Washington researchers wanted to give a definitive answer on whether there is evidence that glyphosate—often sold under the brand name Roundup—is a carcinogenic. They were specifically looking at whether it leads to higher incidences of non-Hodgkin lymphoma (NHL) in humans.

The researchers looked at all published studies available on the impact of glyphosate on humans, including a 2018 study called the “Agricultural Health Study“. They found that people who have been exposed to high levels of glyphosate had a 41 percent higher risk of developing NHL. The outcome did not meaningfully alter, even after multiple sensitivity testing.

To give more context, the researchers then turned to animal and so-called “mechanistic” studies—those that focus on what or how a pathogen or drug does what it does. The team found further evidence to support the link between high exposure and increased NHL risk.

They also note that there was evidence to support an increase in malignant lymphoma, suppression of the immune system, endocrine disruption and genetic changes that overlap with NHL.

With all of this evidence, the researchers arrive at a stark conclusion, saying, “All of the meta-analyses conducted to date, including our own, consistently report the same key finding: exposure to GBHs (glyphosate-based herbicides) are associated with an increased risk of NHL.”

In 2015 the World Health Organization’s International Agency for Research on Cancer (IARC) categorized glyphosate as a probable carcinogen, saying that if exposure is high enough, there was evidence of an increased risk of NHL.

Monsanto has always argued that the scientists ignored important studies when they made this determination. This argument has allowed several agencies—including the EPA and Health Canada—to say there are no credible findings that support glyphosate being cancer-causing.

However, this latest analysis comes on the heels of a plagiarism scandal in Europe, where it was revealed last year that EU regulators had based a decision on whether to reauthorize glyphosate on evidence that was directly lifted from Monsanto’s own internal studies, without giving proper context or a thorough and balanced critique. This wasn’t just a few passages. A report made to the European Parliament found that over half of the text was copied from industry sources, sometimes lifting entire pages. This, campaigners said, explained why the EU’s findings were so different from the IARC’s classification.

The analysis has an added layer of importance. “Three of the study authors were tapped by the EPA as board members for a 2016 scientific advisory panel on glyphosate,” The Guardian notes. “The new paper was published by the journal Mutation Research /Reviews in Mutation Research, whose editor in chief is EPA scientist David DeMarini.”

While obviously this does not directly affect how the EPA might position itself on glyphosate, it does mean that the public is now well aware that several key members of the EPA know glyphosate’s potential as a carcinogen. They also know that several members of the EPA have been critical of the agency for failing to apply its own rules to its review of glyphosate.

Bayer, who now owns Monsanto, has said  this new analysis is “statistical manipulation” that has “serious” methodological problems, and that it ”provides no scientifically valid evidence that contradicts the conclusions of the extensive body of science demonstrating that glyphosate-based herbicides are not carcinogenic.”

The researchers readily admit that their analysis isn’t without its problems. For one thing, there are only a relatively limited amount of independent, high quality studies available on this topic. Furthermore, because of the limited number of studies available, the researchers could not control the population sample sizes the studies used, meaning that they varied quite dramatically from study to study. Yet they found the cancer risk consistently from study to study. For this reason, the researchers stand by their analysis, saying they find the link “compelling”.

So what to take away from this study? Does it prove that there is a risk of NHL for the general public who use Roundup or other glyphosate-containing weed-killers? The data don’t support that conclusion. However, this analysis gives a strong, if not definitive, answer on whether there is evidence that glyphosate is carcinogenic. The answer to that question is yes.

More high quality studies on this topic are needed, because for too long Monsanto appears to have set the agenda on how its products have been reviewed. If nothing else, this analysis should demonstrate the need for in-depth, independent reviews funded by national governments to ensure the highest levels of rigor and transparency.

The EPA has said it is now reviewing this analysis.

Photo credit: Getty Images.


Leanne K
Leanne K4 months ago

Then why do we allow it to be manufactured and sold and used. People are sheep who put money and convenience before others. Until its them or their child then suddenly its an issue

Paula A
Past Member 4 months ago

thank you

hELEN h4 months ago


Anna R
Anna R4 months ago

thank you for posting

Shae L
Shae Lee4 months ago

Thanks for sharing

Mike R
Mike R4 months ago

The production must end. Thanks

Hannah A
Hannah A4 months ago

Thank you

Helen C
Helen C4 months ago

Has never used it.....and never will

Yvonne T
Yvonne T4 months ago


Shae Lee
Shae Lee4 months ago

Thank you for sharing!