What Explains the Different Glyphosate Safety Conclusions?

Kristine Dennis PhD, MPH · July 20, 2026 · Volume 73

If glyphosate was deemed “probably carcinogenic,” why did regulators still approve its use?

Discuss

Transcript

Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.

The International Agency for Research on Cancer, also known as IARC, is the official World Health Organization body that identifies what is and is not carcinogenic. When its 2015 report concluded glyphosate was “probably carcinogenic to humans,” what implications did that have for glyphosate regulation?

First, we have to consider a couple differences between what IARC concludes and what ultimately occurs with regulation. IARC is focused on whether glyphosate is a hazard – whether it has the capability of causing cancer – not necessarily what risk there is from the hazard. You can think of it this way: we know smoking can cause cancer, but if you don’t smoke and are not exposed to secondhand smoke, you don’t have any risk from smoking. The extent and intensity of exposure are what contributes the level of risk.

IARC assessments do not include recommendations for regulatory or legislative decisions. On the other hand, the European Food Safety Authority issues advice on food risks which informs European policies.

How did IARC’s evaluation of glyphosate differ from the European Food Safety Authority’s? Some scientists contend that the IARC’s was, in fact, a more rigorous evaluation as it relied solely on publicly available, peer-reviewed data to make the assessment, while European regulators factored in proprietary information from industry that’s not available to the wider scientific community. Scientific divergences may result from different sets of evidence, different approaches and methods, or different interpretations when weighing ambiguous results. And that seems to be a big part of what is at play here.

But there are also issues that corrupt the regulatory process like “revolving doors” between a regulatory authority and the very industry it is meant to regulate; reliance for safety data from unpublished industry documents, while largely ignoring publications by independent scientists; and covert influence by the industry. While EFSA has tried to address this with a new policy on independence, the same month that its policy came out, it was found that nearly half the experts at the EFSA had conflicts of interest.

With that in mind, let’s get back to the science. IARC considered the association between exposure to glyphosate and non-Hodgkin lymphoma as “limited evidence in humans,” while in EFSA’s assessment, most experts considered the evidence as “very limited” and insufficient for triggering the classification. Despite the limited human evidence, IARC considered the animal data along with strong evidence for two mechanisms, genotoxicity—the ability to damage DNA–and oxidative stress, to be enough to support the plausibility of the weak association in humans.

Glyphosate was up for re-registration in the European Union in 2018. The decision had to consider both hazard-based (like IARC) and risk-based analysis (like EFSA). While IARC’s assessment may not be suitable to calculate practical significances, a risk-based analysis can be challenged if exposure estimates are uncertain.

Ultimately, the U.S. Environmental Protection Agency, EFSA, and others concluded that glyphosate is unlikely to cause cancer and suggested increasing its Acceptable Daily Intake value from 0.3 to 0.5 mg/kg b.w. within the E.U. despite IARCs conclusions. The Acceptable Daily Intake in the U.S. is about triple that, at 1.75mg/kg bw. In 2023, the European Commission reapproved glyphosate use for another 10 years.

Let’s circle back to the exposure question. Glyphosate-based herbicides are the most commonly-used herbicide class worldwide, accounting for more than half of agricultural herbicide use in the U.S. alone. Nearly 93% of the U.S. soy crop and 85% of the U.S. corn crop are treated with glyphosate-based herbicides. To give a sense of that scale, that means more than 250 million pounds (113,400 metric tons) of glyphosate are applied each year to cropland in the United States alone. And it goes beyond soy and corn, including things like wheat, cotton, and fruits and vegetables.

In Europe, glyphosate is used on up to 50% of crops, including olives, grapes, apples, and citrus. As glyphosate is used more, this leads to more weeds that develop resistance to glyphosate, fueling more spraying and ultimately creating a vicious cycle of more spraying, resulting in more resistance, resulting in more spraying. Farmers are now using greater amounts of glyphosates than before, at more time points during year, and in new roles, such as preharvest desiccation, where they spray glyphosate on a crop like wheat, killing the plants and allowing the wheat to be harvested sooner. The long-term effects of this increased use are unclear.

More glyphosate is being used worldwide than ever, but how much is actually getting into our bodies? We’ll find out, next.

Please consider volunteering to help out on the site.

Sources

Acknowledgements

Motion graphics by Avo Media

Topics

Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.

The International Agency for Research on Cancer, also known as IARC, is the official World Health Organization body that identifies what is and is not carcinogenic. When its 2015 report concluded glyphosate was “probably carcinogenic to humans,” what implications did that have for glyphosate regulation?

First, we have to consider a couple differences between what IARC concludes and what ultimately occurs with regulation. IARC is focused on whether glyphosate is a hazard – whether it has the capability of causing cancer – not necessarily what risk there is from the hazard. You can think of it this way: we know smoking can cause cancer, but if you don’t smoke and are not exposed to secondhand smoke, you don’t have any risk from smoking. The extent and intensity of exposure are what contributes the level of risk.

IARC assessments do not include recommendations for regulatory or legislative decisions. On the other hand, the European Food Safety Authority issues advice on food risks which informs European policies.

How did IARC’s evaluation of glyphosate differ from the European Food Safety Authority’s? Some scientists contend that the IARC’s was, in fact, a more rigorous evaluation as it relied solely on publicly available, peer-reviewed data to make the assessment, while European regulators factored in proprietary information from industry that’s not available to the wider scientific community. Scientific divergences may result from different sets of evidence, different approaches and methods, or different interpretations when weighing ambiguous results. And that seems to be a big part of what is at play here.

But there are also issues that corrupt the regulatory process like “revolving doors” between a regulatory authority and the very industry it is meant to regulate; reliance for safety data from unpublished industry documents, while largely ignoring publications by independent scientists; and covert influence by the industry. While EFSA has tried to address this with a new policy on independence, the same month that its policy came out, it was found that nearly half the experts at the EFSA had conflicts of interest.

With that in mind, let’s get back to the science. IARC considered the association between exposure to glyphosate and non-Hodgkin lymphoma as “limited evidence in humans,” while in EFSA’s assessment, most experts considered the evidence as “very limited” and insufficient for triggering the classification. Despite the limited human evidence, IARC considered the animal data along with strong evidence for two mechanisms, genotoxicity—the ability to damage DNA–and oxidative stress, to be enough to support the plausibility of the weak association in humans.

Glyphosate was up for re-registration in the European Union in 2018. The decision had to consider both hazard-based (like IARC) and risk-based analysis (like EFSA). While IARC’s assessment may not be suitable to calculate practical significances, a risk-based analysis can be challenged if exposure estimates are uncertain.

Ultimately, the U.S. Environmental Protection Agency, EFSA, and others concluded that glyphosate is unlikely to cause cancer and suggested increasing its Acceptable Daily Intake value from 0.3 to 0.5 mg/kg b.w. within the E.U. despite IARCs conclusions. The Acceptable Daily Intake in the U.S. is about triple that, at 1.75mg/kg bw. In 2023, the European Commission reapproved glyphosate use for another 10 years.

Let’s circle back to the exposure question. Glyphosate-based herbicides are the most commonly-used herbicide class worldwide, accounting for more than half of agricultural herbicide use in the U.S. alone. Nearly 93% of the U.S. soy crop and 85% of the U.S. corn crop are treated with glyphosate-based herbicides. To give a sense of that scale, that means more than 250 million pounds (113,400 metric tons) of glyphosate are applied each year to cropland in the United States alone. And it goes beyond soy and corn, including things like wheat, cotton, and fruits and vegetables.

In Europe, glyphosate is used on up to 50% of crops, including olives, grapes, apples, and citrus. As glyphosate is used more, this leads to more weeds that develop resistance to glyphosate, fueling more spraying and ultimately creating a vicious cycle of more spraying, resulting in more resistance, resulting in more spraying. Farmers are now using greater amounts of glyphosates than before, at more time points during year, and in new roles, such as preharvest desiccation, where they spray glyphosate on a crop like wheat, killing the plants and allowing the wheat to be harvested sooner. The long-term effects of this increased use are unclear.

More glyphosate is being used worldwide than ever, but how much is actually getting into our bodies? We’ll find out, next.

Please consider volunteering to help out on the site.

Motion graphics by Avo Media

Doctor's Note

This is the second video in a four-part series. If you missed the previous one, check out Glyphosate Declared a Probable Human Carcinogen. Stay tuned for Are Consumers of GMO Crops Exposed to Enough Glyphosate to Increase Cancer Risk? and The Effects of Glyphosate on Children and How to Reduce Exposure.

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