Rounding Up the Evidence on Roundup

Those of you who have seen our videos about our sweet corn will know that this year, for the first time, we’re planting corn that is resistant to glyphosate, a type of herbicide most commonly known as Roundup. Our corn is also resistant to glufosinate, which Syngenta uses as the active ingredient of their herbicide Liberty. Of course, herbicides have been highly controversial in recent years, and perhaps no herbicide is more controversial that glyphosate. These two herbicides interact differently with plants, but the generalities of both are the same. Because we’ll use Roundup in our garden, and because of it’s fame, we’ll focus on glyphosate for this article. Studies have attempted to show that glyphosate causes cancer, and others insist that glyphosate is a threat to the environment. Between my dad’s farm experience, my mom’s chemistry degree, and my biology and agriculture classes, we’ve decided that we’re alright with using glyphosate in our garden, and we’d like to share our reasoning with you. Buckle up, because we’re about to get real technical real quick.


Let’s first discuss how glyphosate works. Glyphosate inhibits the shikimic acid pathway, a chemical process in plants that helps the plant create necessary amino acids. Without these amino acids, the plant will die. Humans and animals don’t have a shikimic acid pathway. We don’t even have the ability to create these amino acids and we have to eat them in order for our body to function properly. So, if glyphosate enters your body, it really can’t do much. It isn’t very reactive with other chemicals in our bodies and essentially will exit the body in the exact chemical form it entered the body. Glyphosate isn’t easily absorbed through the skin either, so even if you would happen to spill some all over yourself, it’s unlikely that any meaningful amount would actually enter your body.


One of the largest claims about glyphosate is that it causes cancer. Most of this claim is based off a 2012 study by Seralini et. al (fancy speak for a guy named Seralini wrote it, but a lot of other people helped) in which scientists fed rats glyphosate and glyphosate resistant corn. The study was published, but eventually retracted after peer reviewers noticed some key issues with the study. The strain of rat used in the study is known to be particularly prone to cancer, meaning that a rat getting cancer during the study may simply be because of its inherent genetic predisposition to cancer rather than glyphosate. Also, the sample sizes used for each test group were too small to accurately use a lot of statistical tests. For those of you who have taken a stats class, you’ll know that certain tests and confidence intervals require minimum data set sizes, typically 30 or upwards. In this study, the sample sizes were around 10, making it difficult for accurate conclusions to be reached. Essentially, the experiment’s design didn’t live up to typical standards for scientific research. However, several of the rats developed massive tumors during the study, and several grotesque pictures were included in the paper. This is a strong emotional appeal – it makes people think that if they use or are around glyphosate, they will end up getting tumors like the rats in those pictures. Without a closer look, it’s easy to conclude that Roundup caused these tumors when that may have not necessarily been the case. Even if the tumors were a result of Roundup, one must remember that the sort of exposure these rats were getting to glyphosate is an extremely abnormally high amount. They were being fed glyphosate in their water, which if you keep reading, you’ll understand is extremely unlikely to ever occur in real life. If you’d like, you can read the original Seralini study here.


Others say that glyphosate is dangerous to the environment. One of the main concerns with herbicides is runoff from fields into rivers and lakes. Glyphosate actually does a pretty good job at binding to the soil and when applied responsibly produces little to no runoff. Typically, it just hangs out in the soil until some bacteria come and break it down into smaller, more easily digestible parts. When a plant that is treated with glyphosate dies, half of the chemical is broken down within 8-9 days. So, glyphosate is probably safer than a lot of other herbicides and chemicals when it comes to environmental safety.


There are some credible concerns about the toxicity of products containing glyphosate, but most concerns come from the other chemicals mixed in with glyphosate. Roundup, or any herbicide, is most likely not pure glyphosate, and those other chemicals may be more harmful than glyphosate is itself. Because of this, and because glyphosate is a chemical, we always make sure to treat it with extreme care and caution. While we believe that the benefits of glyphosate and glyphosate tolerant corn outweigh the costs, we still do our best to handle the chemical in a safe and responsible way.


At the end of the day, we must all remember that farmers (and gardeners like us) are in the business of creating more food safely and more efficiently. Glyphosate is a tool that has helped farmers feed millions more people and increase output while decreasing the time and effort required to weed their fields, which allows farmers to grow more food. Farmers have even more reason to be afraid of a toxic chemical than most of us – they have the highest exposure to the chemical themselves. So, while there is a lot of skepticism and fear surrounding herbicides, including glyphosate, remember that those who developed it and use it daily trust that it will not harm them or their families.




  1. It is a breath of fresh air reading an article that speaks plainly about the effects of glyphosate on corn and human contact with the chemical. Generally the public is only exposed to propaganda from one group claiming glyphosate is the devils nectar or from the other camp exuding that it is the end all and be all in crop production. Your article is well balanced and informative showing that as with all modern herbicides, proper complete studies need to be carried out before a firm conclusion can drawn of all effects that can take place with usage. Nice work.

  2. Loved the article. Thank you for picking thru the emotional issues and pointing to the facts that enable folks to make an informed decision.

  3. Thanks for the factual presentation of this issue. Very well written and to the point in terms the average person can understand.

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