Glyphosate is a key ingredient in the widely used herbicide Roundup.

Glyphosate is receiving a lot of undeserved bad press lately, and it is highly misleading. We use many chemicals in our daily lives, and they are safe most of the time because they are used below levels that are harmful. Claims that glyphosate (the main ingredient in Monsanto’s Roundup herbicide) is unsafe are not supported by valid scientific studies.

Fred Behringer

The recent CT Viewpoints article, “Use Glyphosate with Caution,” by Nancy Alderman was commendable, and its advice to use products as directed is certainly a welcome reminder. However, it perpetuates many misconceptions and fears. Glyphosate is among the safest herbicides in use today. It inhibits an enzyme in plants (but not animals), it decomposes rapidly in soil, and if consumed it largely passes through the body.

Every chemical is toxic at high enough concentration. Caffeine, an organic chemical that many of us are exposed to every day, has a toxicity 10 times that of glyphosate. Because of the extreme sensitively of modern analytical chemistry, traces of glyphosate can be found in foods, but those amounts are hundreds of times below harmful levels (just like many other chemicals we are exposed to daily).

Claims have been raised that glyphosate causes non-Hodgkin’s lymphoma, and Monsanto and its new German owner, Bayer AG, face thousands of lawsuits by people blaming Monsanto’s glyphosate-based herbicides for their diseases. In 2015, the International Agency for Research on Cancer (IARC) added glyphosate to its list of chemicals “probably carcinogenic to humans.” This analysis is flawed and plagued by conflict of interest. Its conclusion has not been supported by studies that adhere to scientific standards.

For starters, the IARC lists coffee and red meat as “probably carcinogenic to humans.” It is also important to understand that, instead of “risk analysis” used by many scientific studies, the IARC uses “hazard analysis,” which sets a much lower standard and has resulted in conclusions based on questionable interpretation of data.

This explains why no regulatory agency around the world (15 in all) considers glyphosate to cause cancer. This includes the World Health Organization, which oversees the IARC and which does not support the IARC’s hazard analysis conclusions. In one of the most recent reviews, Health Canada stated: “No pesticide regulatory authority in the world currently considers glyphosate to be a cancer risk to humans at the levels at which humans are currently exposed.”

Here is a graphic summarizing the assessment of glyphosate safety from 15 regulatory agencies from around the globe, citing epidemiological data and evidence from animal studies, and saying products containing glyphosate are safe if used according to the label instructions.

Many articles on glyphosate select studies that are not supported by the scientific consensus. There have been thousands of studies on glyphosate. I could cite 20 studies that show it was associated with a reduction in cancer. This includes one from the prestigious journal, Nature, which purports that glyphosate may cure malaria. Are any of these significant? Very likely not! Just because something is published does not make it true. It’s not uncommon for published work to be inaccurate. The tadpole and the NHL studies cited by Alderman have their shortcomings and are not representative of the scientific consensus on glyphosate safety.

One way to put this in perspective is to contrast glyphosate to alcohol. Alcohol is a known carcinogen (even the IARC and the scientific community agree on this). It causes head/neck, esophageal, liver, breast and colon cancer. Yet there is no movement to ban alcohol and probably rightly so, as the risk is relatively low. A double standard is being applied to glyphosate.

We hear a lot about “fake news,” and we also generally agree to value science and technology. However, time and time again we see sensational, unscientific and inaccurate information spread in the news media, social media and our conversations. This gets in the way of solving real problems. Pick your topic – climate change, vaccines, it goes on – for various reasons, some probably innocent but often for monetary gain, information is selectively chosen to support an agenda. The current glyphosate scare is a case in point.

Glyphosate’s risks have been vastly exaggerated. Not only is it one of the safest herbicides, it has contributed to more environmentally friendly agriculture and helps combat climate change. The unfounded backlash against glyphosate will do us harm, not good.

Fred Behringer holds a Ph.D. in plant physiology and owns Surveillant LLC, an analytical chemistry laboratory in Old Lyme.

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39 Comments

  1. A thank you to the author for providing a responsible, science-based counterpoint to the attack on the herbicide glyphosate. The sub-headline “Cautious use is warranted, but risks have been vastly exaggerated” seems to properly frame Mr. Behringer’s message.

  2. Mr. Behringer needs to go back to school. Many of his claims about glyphosate are frankly false and based on Monsanto’s long use of favorable but unsubstantiated talking points. For example, he claims that

    “Glyphosate is among the safest herbicides in use today. It inhibits an enzyme in plants (but not animals), it decomposes rapidly in soil, and if consumed it largely passes through the body.”

    What he fails to realize is that the bacterial microbiome in humans and livestock contains that same enzyme found in plants. Many studies have demonstrated that glyphosate kills off beneficial gut bacteria in humans and other animals, allowing for overgrowth of pathogenic bacteria such as Clostridium botulinum.

    He asserts that “glyphosate is among the safest herbicides,” but the reality is that glyphosate herbicide contains several so-called “inert”ingredients such as strong surfactants like POEA that are much more toxic than glyphosate. The EPA’s continued defense of glyphosate safety is based on questionable research on glyphosate alone. The agency has never required safety testing of actual glyphosate formulations like Roundup as they are formulated, sold and applied. As a consequence of that inadequate safety testing, Monsanto/Bayer is currently facing 18,400 lawsuits in the US alone alleging that frequent users of glyphosate herbicides developed non Hodgkin’s lymphoma. Please explain away that coincidence, Mr. Behringer. Those interested in learning more about the problems with glyphosate-based herbicides should consider reading Carey Gillam’s well-documented book, “Whitewash: The Story of a Weed Killer, Cancer, and the Corruption of Science.”

    1. Hi Factchecker, we welcome your comments but please note that our guidelines require that comments be limited to 1,000 characters. We will not be able to approve comments that exceed that limit going forward.

    2. Your claims are based more on supposition than fact. The safety testing that Glyphosate has received, not only in the USA but also around the world with such luminary groups as the CSIRO in Australia, ANSES in France and many others, has been anything but inadequate. 18400 lawsuits means…exactly nothing, until or unless they come to trial and are adjudicated on. Right now, I’d say they’re mostly the result of a bunch of greedy lawyers who think they can get a jury to award lots of money because the defendant is an unpopular company. Gilliam’s book was debunked years ago.

      1. Well I’d say you clearly aren’t familiar with the details of the issue. And the excuse that 3 trial verdicts, and judges agreeing with the verdicts, are the result of Monsanto being unpopular is ridiculous. That excuse was made after the first trial over a year ago.

        Also, don’t forget there were over 4000 lawsuits already filed prior to the first trial win. These “greedy lawyers” were taking on big risk for several years.

        Have you applied a lot of Roundup?

      2. That is no “excuse” It is a real shame that the Judge allowed testimony that is or bordered on perjury and that the jurors ruled against the truth.

    1. Absolutely! Also, the elimination of milkweed has been an off-target effect of spraying Roundup on fields of Roundup-tolerant corn, soy, alfalfa, sugar beets. Milkweed has typically grown alongside or between crop fields.

      1. Milkweed reduces yield when not controlled. As has been pointed out to you before. Increased yields means less land where glyphosate is sprayed. And that you repeatedly ignore both that illegal logging in Mexico is part of the problem. Also as monarch numbers before farming became extensive is unknown. There is no true basis for comparison.

  3. This is simply the same ole industry propaganda that’s been spewing out for years. The article first focuses on levels of those exposed but yet there are hardly any biomonitoring data whatsoever that exist, so we really don’t know what the levels of those using the herbicide really are. Period.

    The caffeine, similar to table salt comparison, is based on acute toxicity and not chronic toxicity, which the carcinogenicity of glyphosate and glyphosate based herbicides surely are based. Don’t be misled.

    The industry flag really flies high when the author attempts to discredit IARC. Just look up Monsanto’s “Orchestrate Outcry” initiative or the $17M Monsanto spent in 2016 alone to discredit IARC. Saying IARC is “plagued” with conflicts of interest makes me wonder what the author must think about the mountain of evidence that points to Monsanto’s suppression and manipulation of science? It’s like this author has been living on the moon playing with his chemistry set since March 2015.

    The regulatory agencies have been influenced by manipulated by ghostwritten science and subject to heavy lobbying. So, of course they’re not going to just come out and say – “yep, we were wrong for 45 years, sorry about that. Monsanto really fooled us”. This is going to take many years to undue, already has, and there are political forces at play which will only further delay the inevitable.

    Of course he also included glyphosate based herbicides are“safe if used according to labeled instructions”. This is a script used by the agrochemical industry for over 5 years now and if that’s the case, and the author is such the expert, why does UK require gloves, coveralls, & boots when applying glyphosate herbicides, or AU require elbow length pvc gloves and coveralls, or CA require gloves when mixing and repairing spray equipment, meanwhile the US requires pants, long sleeve shirt, shoes and socks?

    You see there is a disconnect among the regulatory agencies and applying glyphosate based herbicides following US labels would be a clear violation in UK, NZ, AU, IE, etc., to name a few. None of the regulatory agencies in these countries would consider glyphosate based herbicide applications safe the way they are applied in the US.

    The fact of the matter is that this author doesn’t know if glyphosate or glyphosate based herbicides are safe or not. He is trying to influence you the reader to believe that the herbicide now in all of our children is safe. Why? Don’t buy into this nonsense.

    Do your own research and come to your own conclusion. The data he shrugs off as insignificant has resulted in Germany banning glyphosate in 2023, France in 2021, Austria already in a complete ban, plus many US, FR and CA municipalities having banned or are in the process with the list growing bigger everyday. And let’s not forget three juries PLUS three judges clearly sided with plaintiffs stating that there’s enough credible evidence that glyphosate is carcinogenic and Monsanto is deserving of punitive damages. How many more trials must Monsanto lose before folks like this stop trying to influence our thinking.

    1. Hi youcantbelazy, we welcome your comments but please note that our guidelines require that comments be limited to 1,000 characters. We will not be able to approve comments that exceed that limit going forward.

    2. Of course they can’t say they were wrong. That would be lying. The AHS and slightly lower NHL rates alone clearly show that your claims are impossible. The Data has not resulted in the German action. Their own BFR agrees with the author. These bans and restrictions re the result of people like you wrongly applying political pressure to spineless politicians. https://www.bfr.bund.de/en/a-z_index/glyphosate-193962.html

  4. The only studies that have been done on earthworms response to glyphosate don’t bode well for one of the most important creatures on our planet, such as the earthworm is. As just one example, a study from 2015 carried out by researchers from the University of Natural Resources and Life Sciences in Vienna showed that casting activity of earthworms had nearly disappeared from the surface of farmland within three weeks of glyphosate application. I would say that is profoundly serious and reason enough in itself to outlaw glyphosate entirely.

    Our health is dependent on the health of soil biology. But you will never hear one of the industry-connected lab masters that write this stuff venture into this territory. Either they know, and so observe a damning silence, or they actually think human health exists in isolation to the health of a nature that gives us the food that forms our bodies.

    1. Where is the link to this “”study”” I have found that many of the oppose make these claims and when no link is provided. They are usually blowing smoke. Also, no ban is justified by one outlier study. Especially if not replicated.

      1. It is this study here https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4542661/

        It is really a piece of junk science conducted by people who seemingly know nothing about agriculture or about how herbicides are used.

        They sprayed pots of plants with a Roundup formulation at the equivalent of 3.7 kg glyphosate/ha. This is roughly 3 times the highest rate used in field crops. They did it again the next day. Then two days later, presumably because the plants were still not showing any symptoms, they switch to Roundup Speed, which contains pelargonic acid as well that gives a fast burndown, and applied that at the equivalent of 5 kg/ha of glyphosate.

        More than 2 weeks after the plants died, not unsurprisingly earthworms became less active than in the untreated pots. Among other things, earthworms feed on dead leaves and other organic matter. No plants means no further inputs of carbon into the system. There were no controls to account for the lack of growing plants, so the whole study doesn’t tell us much, except that the authors don’t know how to design an adequate study to test the effects of herbicides.

      2. Hi Chris, we welcome your comments but please note that our guidelines require that comments be limited to 1,000 characters. We will not be able to approve comments that exceed that limit going forward.

      3. This doesn’t change the concerns that farmers have about soil quality degradation in the context of long-term use of Roundup in conjunction with herbicide-tolerant crops.

        In the US, these commodity crops cover millions of acres, and farmers aren’t well-supported economically to incorporate the kind of rotations that might alleviate the problem. I think your experience in Australia might not match ours here in the US.

      4. So the real problem is not too much glyphosate, but not enough crop rotation?

        I am perfectly familiar with US broad scale agriculture, seeing as how I have worked there and have relatives farming in the US.

        The only group that seems to think glyphosate causes soil quality degradation are the organic farming sector as in the piece from the NYT you linked to. The fact that they do so based on poor quality evidence like the worm study above really shows how weak their opinion is.

        There is too much glyphosate being used in the US, but it is resistant weeds, not soil quality degradation that is the outcome. If farmers went back to tillage because glyphosate was banned, that would cause soil quality degradation.

  5. The author could have mentioned that a definitive prospective study of over 52,000 agricultural workers found no links between glyphosate and cancer. Basically, it proved that glyphosate does NOT cause cancer in humans.

    Here is the link to the study findings:

    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6279255/

    All the jury awards against Bayer/Monsanto have ignored this evidence which is as strong that scientific evidence can get without a randomized clinical trial.

    I should add that I have a PhD in biostatistics and do research in cancer epidemiology. I do not have any funding from industry and have never received any funding from either Bayer or Monsanto.

    1. The study referenced and linked to by Charlie Hall, is the Agricultural Health Study. It found an increase in incidence of acute myeloid leukemia (AML), in those most regularly exposed to Roundup/glyphosate.

      The study which showed a 41% increased risk of non-Hodgkin’s lymphoma was a “meta-study” which looked at several epidemiological studies. Like those epidemiological studies, the meta-study concluded that Roundup is correlated to an increased risk of developing NHL.

      The IARC, comprises various groups of highly independent experts, who review only independent peer-reviewed studies. The group which evaluated glyphosate determined it to be a probable carcinogen. This was NOT just based on epidemiological studies. The IARC found “sufficient” evidence from animal studies that glyphosate caused oxidative stress/genotoxicity.

      Most US residents have glyphosate/AMPA (metabolites) in their urine. They are chronically exposed through their diets. Glyphosate is present throughout our food and water supply.

      The presence of glyphosate/AMPA has been correlated to fatty liver disease and shortened gestation periods, both in humans. These findings will hopefully be explored further.

      In the meantime, I hope people will do what they can to reduce their exposure.

      Regarding the original post/article, saying that “the World Health Organization, which oversees the IARC and which does not support the IARC’s hazard analysis conclusions.”
      is misleading. The WHO does not take any stance on the findings of the IARC, but phrasing this as “does not support the IARC’s hazard analysis conclusions” makes it sound like the WHO disagrees with the IARC.

      1. Hi Lisa, we welcome your comments but please note that our guidelines require that comments be limited to 1,000 characters. We will not be able to approve comments that exceed that limit going forward.

      2. Your first link was about a report an Ag Dominated committee of the WHO. The WHO has not accepted that report as their official position. The WHO and the IARC position is that glyphosate is a animal carcinogen and a probable human carcinogen too. Science20 is an industry AstroTurf site and the article is written by a well known industry propagandist.

      1. You have cited an article that uses the same study that Charlie Hall cited. Papa Ray posted peer reviewed science that shows glyphosate causes a 41% NHL rate among glyphosate applicators. You have made a redundant argument.

      2. You are using the same argument that cites the same study that Charlie Hall already posted. With two conflicting studies there is obviously no settled science that shows glyphosate is safe. Bayer-Monsanto has lost three lawsuits in a row when the the industry used that study as evidence. The jury didn’t buy it after hearing all the testimony. Smart folks will avoid this carcinogen until it is proven to be safe by independent scientists.

  6. Germany the home of Bayer is in the process of banning glyphosate’

    “NOTHING TO SEE HERE …MOVE ALONG”

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