Does Glyphosate Cause Cancer?

Glyphosate and cancer. This is something we are hearing so much about, seemingly all of the sudden, with major stories breaking in the last week. Just last Friday, a court case in California resulted in a $289 million dollar payment to a man named Dewayne Johnson, who claimed his years of using glyphosate (also known as Roundup) caused him to develop cancer. A few days before this story broke, glyphosate use was suspended by a judge in Brazil pending a government reevaluation of its toxicity.

What is going on here?

I am a farmer who uses glyphosate. My dad started using it decades ago, and it has absolutely been the single greatest invention in agricultural history. And it is unequivocally, fantastically safe. It is one of the lowest toxicity herbicides we use on our farm. It is less toxic than alcohol. Less toxic than caffeine. So what is all this about?

Why Do We Need It?

I am apart of a multi-generation family farm in southeast Saskatchewan, Canada. We grow canola, wheat, durum, peas, lentils, flax and soybeans, along with a few other crops. I farm with my sister, my mom and dad, my brother-in-law and my wife and two little boys. I love what I do.


In my part of the Canadian Prairies, we farm in some pretty dry conditions. Our average growing-season rainfall is about 9 inches, or 225 mm. Snow and fall rains provide us with another 4-5 inches. This is semi-arid agriculture, where the next rain really can provide the difference between profit and loss. So, we work very hard to use every drop of moisture we get. We have to. That means we cannot allow weeds to grow, and we must leave the soil undisturbed as much as possible – we do not want to till our land if we can at all avoid it.

What glyphosate allows us to do is to kill every weed in the field before the crop emerges. In the days before glyphosate, my grandfather had the very same goal – but he only had one way to do it. He had to work the land, over and over and over. The goal was to make it absolutely black. That was the only tool they had, and sadly, it was the direct cause of the great dust storms of the Dirty 30’s. Why would we ever want to go back to that?

Moreover, glyphosate allows us to control weeds in certain crops as they grow. Canola and soybeans are two crops I grow that are genetically engineered to be resistant to glyphosate. This means we can spray it over the crops, while they are young and struggle to compete with weeds, to keep them clean. We use different chemicals in other crops to accomplish the same thing, but none have the broad spectrum control that glyphosate has – and few of them are as cheap, or as safe.

The introduction of Roundup-Ready crops, including corn, soybean, canola, cotton and so on, has allowed for safe, simple, very cost-effective weed control.

Is It Safe?

This is the big question, and if you follow the news at all, I could certainly understand if you don’t feel it is safe. You may think it causes cancer, autism, and any number of diseases. That is what you’ll find on the Internet.

Here’s the experience of a farmer.

I use glyphosate hundreds of hours every year. I load and run our sprayers (along with farm employees and my family) over thousands and thousands of acres spraying glyphosate. My son rides in the sprayer with me sometimes. And I don’t worry at all about glyphosate being dangerous.


Here’s the thing about spraying a chemical like glyphosate. An acre of land is 43,560 square feet, which is a little smaller than an American football field. On that acre, 360 grams of glyphosate active ingredient is sprayed. Put another way: 2 cans of beer of glyphosate sprayed over an area almost the size of a football field. That’s .015 mL of beer on each square foot – and that includes the solution the glyphosate active ingredient is suspended in. That is an incredibly low concentration. A standard “drop” of water is .05 mL. That’s less than a third of a drop of water!

Sure, some chemicals are highly toxic in even very small doses. Glyphosate is not one of those chemicals. Its LD50, or the lethal dose for 50% of rats in testing, is 5,600 mg/kg. The LD50 for caffeine? 192 mg/kg. Don’t panic about your coffee though – that’s still very safe!

Does Glyphosate Cause Cancer?

While I have explained that an acute dose of glyphosate is safe, that doesn’t really answer the cancer question. That is something that would accrue over many years, and may have little to do with the aforementioned LD50. Has this been studied thoroughly enough to be sure glyphosate is indeed safe? And has it been studied by independent organizations and scientists?

John Giesy, a professor and research chair in environmental toxicology at the University of Saskatchewan, would argue that yes, glyphosate is safe. He has quite the resume, as a professor or honorary professor at six other universities and is the most cited author in the world in the combined fields of ecology and environmental sciences. In an article you can find here, when speaking about the subject of cancer, he had this to say:

“Certainly you wouldn’t wish it on anyone. But whether it’s caused by glyphosate, in my opinion, is highly unlikely.”

In 2015, the International Agency for Research on Cancer (IARC), a WHO agency, claimed that glyphosate was a  “probable carcinogen”. Glyphosate is hardly alone in this category, with such partners as high temperature frying, working as a hairdresser, red meat or shiftwork. Stuff that is actually carcinogenic on their list? Alcoholic beverages, sawdust and processed meat (to name a few). Yes, beer and hot dogs are considered more likely to cause cancer than glyphosate (source).

It was this IARC report that started all of this, and there are some real questions as to their methodology. In fact, according to the then- European Crop Protection Director, General Jean-Charles Bocquet,

“From the summary conclusions it appears that IARC has made its conclusions as a result of an incomplete data review that has omitted key evidence.” (source)

It was recently discovered that the IARC had removed findings from studies that concluded glyphosate was not a carcinogen before they published the final version. They also used the infamous, now retracted Seralini rat study in their analysis.

The fact is that numerous organizations conclude glyphosate is safe, including the UN’s Food and Agriculture Organization, the European Food Safety Administration, Health Canada, the German Risk Agency, and on and on. A massive study run on 89,000 farmers and their familes in Iowa and North Carolina since 1993 has failed to find any link between glyphosate and cancer. How much more evidence do we need?

I need glyphosate on my farm. It helps me be more sustainable, both environmentally and economically, it helps me protect my soil from erosion and build soil health, and it helps me sequester carbon, reducing greenhouse gas emissions. The fear over glyphosate is unfounded, and we need to slow down and have a real discussion about it. If you want to come to my farm and see how we use this contentious chemical, please let me know. My door is open for anyone who wants to have their questions answered.

38 Thoughts

  1. Jake, Thank you from the bottom of my heart for all that you and your family do! If you’ll ever allow me, I would be honored to visit your farm and have a face to face conversation with you. I would love to share your post on my social media. Will you allow me to use the picture of your family in my post? If I simply link to it Facebook won’t show it to many. If I use a photo, it considers it as a photo post and is more likely to show it to others. I am an organic farmer. I’ve been trying to grow as much as I can over the years but I know without a shadow of doubt that unless everyone have their own organic garden in their back yard we would never be able to feed all the population in this world. And I myself still depend on the grocery store!! I want you to know that you and your family are most appreciated for what you do. We could not have lived here without you guys! It pains me that the media makes your life harder instead of supporting you. Please let me know if I can use the first photo in your blog post.

    Blessings! Lee,

    Sent from my iPhone


    1. Thanks so much for your kind comments! It’s wonderful to hear support from organic farmers too – we are all on the same side! You may absolutely share this post on whatever way you see fit. Thanks!

      1. Thank-you Jake, This is the best written article I have read about Glyphosate and why we as farmers need this option in growing crops today. I have always wanted to be able to say that in words the public can understand and you have hit the nail on the head with your story. Well done.

      2. You are only posting comments that are supportive of your position and that is completely dishonest. Why did you not post my comment which refutes your position?

      3. My apologies! I don’t always catch all the notifications. I always approve comments (unless they are inappropriate of course), whether I agree with them or not.

        Now as to your previous comment. On the subject of non-Hodgkins lymphoma, the author’s comments on Reuter’s reporting that the IARC results are no longer relevant is rather late. The IARC’s conclusions were never subject to rigorous science, and the authors have been shown to have removed findings from studies they did not agree with, as I pointed out in my post. The IARC was the only organization to make this conclusion as well, with other organization such as Health Canada, the European Food Safety Administration, the German Risk Agency and so on all coming to the conclusion that glyphosate does not cause cancer. As to the author’s other concern, if there is a link between AML, this would be a concern only to applicators, who use glyphosate directly – not for consumers, where the residues are far below even the extremely safe maximum residue limit. Those of us who apply glyphosate, like any agricultural chemical, always should use proper PPE when mixing and loading it.

      4. The IARC is a semi-autonomous offshoot of the WHO. They are not one and the same. Regardless, the IARC is the only organization to come to the conclusion that glyphosate “probably” causes cancer – the same designation they give to processed meats. We drink a confirmed carcinogen regularly (alcohol) and worry little about it.

      5. the IARC are not an offshoot of the WHO, they are the International Agency for Research on Cancer (IARC), the specialized cancer agency of the World Health Organization, If they say it’s most likely carcinogenic then why would you keep flogging this stuff. And there are many other studies showing the same. You put so much time into this that I can only assume that you have a strong connection to Monsanto and something more to gain. And if alcohol is carcinogenic then we can choose not to consume it and we certainly don’t put it into childrens breakfast cereal as you are doing – that’s unconscionable.

      1. Here’s the thing about peer-reviewed journal articles in isolation: either of us can continually go back and forth one article at a time until we get through them all. Because each article can show different results, it is only a summarization of the literature that really concludes anything. So rather than go back and forth on this to the end of time, here is a better article than mine that really delves into the science. Andrew Kniss, weed scientist from the Department of Plant Science at the University of Wyoming, took a deep dive into the literature on glyphosate and cancer after the August California court ruling. He concludes with this:

        “So again, I’m not sure what the jury saw in this most recent case. But based on the evidence I have seen, I remain thoroughly unconvinced that glyphosate causes cancer.”

        This guy has hundreds of citations and is a highly regarded scientist. Even better, he can explain this stuff in a way I can understand. So check out what he had to say.

      2. Jake, you are confusing opinion by a professor with actual peer reviewed scientific studies. They are not the same thing. There are many of these studies that show conclusively that glyphosate and Roundup are harmful in various ways. These studies have been accepted as valid by peers because the studies are well done, rigorously reviewed and repeatable. Opinions are just opinions and I wouldn’t want to bet my children’s health on them which you seem willing to do.

  2. Jake – very well stated and supporter. Your personal story and experience is valuable and a ‘must read’ for anyone who has questions about glyphosate. Thank you!

  3. This is very well written Jake. Thanks for taking the time to wrote such a thoughtful piece.

  4. I have not seen a better article on this topic for a lay audience than this one. Thanks for your calm and considered approach. I hope it is shared widely and goes some way towards addressing the mounting hysteria. Great job.

  5. Thank you for such a well written article. We farm in the dry SW corner of Alberta. We also rely on conserving moisture for the hope of a crop and glyphosate has revolutioniszed how we do that… of course we don’t drink or bathe in it but through following the label, like we do with all chemicals, and the safe use of handling with our gloves and masks, we will be using it for years to come. Jeff Hammond.

  6. Jake
    As a retired grain farmer and avid supporter of modern agricultural farming systems ….including the use of GMO’s and of course glyphosate, I salute you on your very complete explanation of how farmers have improved their stewardship of the soil. At times we feel overwhelmed by the constant bashing we receive from the uninformed public. Keep up the good fight !

  7. Serolini’s group wasn’t looking for cancer thet just wanted to see what happened, the tumors became cancerous so by protocol they were required to let the experiment continue.

    Glyphosate is a systemic chelator and if you think it’s not poison drink it.

    If you’re smart enough to not do that admit the labels on the sht are true, it’s a poison and causes cancer by the science, the Serolini affair established a date of awareness that is why there’s criminality involved in these court awards.

    Go drink Roundup, put it in your pancakes, it’s in the food in traces anyway what’s the difference?

    1. The Serolini study was retracted because the results were uninterpretable. The sample size was too small, there was no statistical analysis, and this strain of rats are well known for their propensity for developing tumours. In fact, many scientists charged that the rats were not treated ethically. Defending this study is impossible and unethical.

      Everything is poisonous. But the dose makes the poison. Glyphosate is low toxicity compared with most other agricultural chemicals and, in fact, lower than many household items and many things we consume every day. “Drinking glyphosate” is not a valid comparison. Drink a glass of salt and see what happens. The glyphosate residue in our food is extremely low. Governments set maximum residue limits that are exceedingly low – an order of magnitude lower than the safest possible amount. Glyphosate has not been found to exceed that MRL in almost all cases, and where it does exceed it, it is very, very small.

  8. I appreciate your comments on Glyphosate and how it is not the root cause of cancer. The one thing that gets me about the lawsuit in California, being a trained applicator, I know what is expected of me whenever I use any chemical. This includes using the required PPE, knowing what the wind direction and speed is, and also knowing that if I am getting drift in my face, I am doing something incorrectly.
    This man indicated that he came home from work covered in Glyphosate and other chemicals, clearly he was either not a certified applicator or simply did not care for himself or the environment.
    The question comes to mind, what else was he mixing in his tank? Was he cutting it with 2,4 D, or other products that do not mix for these applications? These are the questions the public will not ever know.
    Again there are so many unanswered questions but I thank you for your testimony.

    1. Completely agree JD. Just because the pesticides we use are at extremely safe levels in our food doesn’t mean they aren’t still potentially hazardous to those of us applying them. Proper PPE is definitely important. While I have sympathy for Mr. Johnson, does he not bear some personal responsibility for not looking after himself? You’re right – other chemicals could have been the cause. But unfortunately, it was Roundup that took the blame.

  9. This was a very well written article Jake. However, we also farm in SE Sask using 100% organic farming practices. We end up with pretty phenomenal crops every year. Sure we have a few weeds, but all the birds, insects and animals need to eat too. They can’t all eat wheat, or canola, or whatever is being grown for thousands and thousands of acres. If we are going to survive as a human race monocropping can absolutely not be the way of the future. We need the birds and the insects and most importantly we need the bees. I just talked to a bee farmer last week whose bees are struggling and he doesn’t know why. No one knows for sure that it’s glyphosate that’s causing bees to die but I think it’s sure worth considering when the projection is that we will only survive for a few years if the bees die out. What I know for sure is that glyphosate is in fact spreading to places it is not wanted. My family has farmed organically since 1892 and two of our crops just tested positive for glyphosate. A neighbour who hasn’t sprayed his land in over 25 years and is not surrounded by chemical farms tested and found glyphosate in his soil.
    I believe that both conventional and organic farmers can and should thrive, but when a product like glyphosate starts to spread to organic fields and causes farmers to lose sales, it becomes a bigger issue. It is not tested for very often because the test is extremely expensive.
    I salute you for living the farm life, I know the heartache and strife that can come along with being a farmer. Our livelihood depends on many factors that are out of our control and it is not an easy road, but it is a good one. I just wanted to share my humble opinions, from one farmer to another.

    1. Thanks for the comment Nicole! All types of farms have their place in the ag industry, and it’s nice to hear from an organic one. My question to you is at what concentration is glyphosate found in your crops? Parts per million? Per billion? At that level of testing, can anything be found? False positives become a real problem at that level. Also, I submit that my 8 crops, one of which bees like (canola), is far from monocropping. Realistically, we’ve been monocropping for 10,000 years, since agriculture was born. I’m not convinced that’s really a problem. Furthermore, I ask what’s worse – detecting trace amounts of a very safe chemical, or dust storms, starving children and poor farmers? I’m not trying to be argumentative or fear-mongering, but, based on the science I’ve seen and read, along with my own experience (there are organic farms in the area) I believe that’s the reality of a world without glyphosate. Thanks again for your comment and good luck with your crops this year!

  10. We need to remember that round up is a chelator. It ties up nutrients.
    And the over use is a problem.
    We can potential burn off every field in the spring. Spray the canola 2 times and decicate every crop on the farm in the fall. (Not the round up ready canola of courses and your seed.)
    I have not decicated any cerials for the last 4 years.
    And I think I will have too this year…its a tool I can use.
    We need to keep things in balance.
    In the future the round up that is so fantasticaly safe will have weeds that don’t die when you spray them.
    We need to be open to new technology and mechanical weeding.

  11. It seems that peer reviewed science means nothing to Jake. He reminds me of the anti-science climate change deniers who can ignore the worldwide scientific consensus and say that all those thousands of scientists from dozens of countries are frauds. There are many dozens of published peer reviewed studies showing the harms of Roundup. Here’s one more study and I’m done here:

    1. Well that’s a rather ridiculous comment. The consensus on climate change is very much like the consensus on the safety of GMOs and glyphosate. This is my final comment.

  12. I farm in Iowa, unfortunately use some RR corn and beans and don’t like it. Our veterinarians have opened our eyes to the literature/studies cited by Dr. Huber et al. The chelation that occurs affects the gut’s bacteria. The correlation to autism and cancer and Parkinson’s is certainly not something I enjoy reading about, but the evidence is astounding. There are traces in all the food we consume. My vet testified at The Hague about glyphosate, a rather discerning group I might add.

      1. Thanks for the comment Dell. Dr Don Huber has been passing very hard on this message for several years now. The reality is that he has very little evidence to back up his claims and no respected journal will publish what he has to say. His tours are largely funded by organic and anti – GMO groups. In fact, even organic advocate Rob Wallbridge has heavily criticized Huber’s complete lack of evidence for his claims. Huber is not only lacking facts, but deliberately attempting to scare an uninformed public in order to further his career. You can read more here (this article references journal articles you can peruse more closely if you wish)

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