Several years ago I was going to write a post about Roundup and glyphosate, its active ingredient, but decided against it because several very good science-based reports were produced by others. Unfortunately, those reviews were not directed towards gardeners and based on frequent discussions on social media, the message is still not getting through to the gardening community.
My goal in this post is not to do my usual deep dive into Roundup, but instead I want to give readers a summary overview of the facts along with references containing more details. I hope that putting all of the information in one spot will make it a useful tool for discussions in gardening social media groups.
Roundup vs Glyphosate
Roundup was originally produced by Monsanto and it contained glyphosate as its active ingredient. Most people recognize and use the name Roundup. Unfortunately, Monsanto (now Bayer) has decided that since this brand name is so well known, they could use it to promote other products, some of which don’t even contain glyphosate.
One Roundup product marketed in Europe is vinegar with no glyphosate, and some products contain both glyphosate and another herbicide.
We really should be talking about glyphosate and not Roundup.
Roundup and Monsanto
Conversations that go something like this, “Roundup is toxic because I hate Monsanto” are illogical.
If you hate Monsanto – that is fine. But your love or hate of the company does not change the chemical properties of glyphosate. One has nothing to do with the other.
Does Glyphosate (Roundup) Cause Cancer?
The general public is more convinced than ever that glyphosate (Roundup) causes cancer because of the recent court cases. I’ve discussed this in detail in Roundup (Glyphosate), Cancer and the Courts.
The result of a court case is the sum opinion of the jury, and it does not represent the scientific facts. There is no doubt that the majority of general public hate Monsanto and Roundup, and they truly believe Roundup causes cancer. But that belief does not make it true.
One of the largest agricultural human heath studies has been following workers using glyphosate, for 20 years, and reported, “Overall rates of cancer in the study remain lower than in the general population, especially cancers of the oral cavity, pancreas and lung.”
The science is quite clear on this, there is no evidence that glyphosate causes cancer and most global health and safety organisations agree. The following infographic was prepared by the Genetic Literacy Project, a group promoting truth in science.
The EU Joins the Group
Update: July 26, 2021. I just saw a report from the EU (European Community) that reviewed the science on glyphosate. This 11,000 page report, looking at over 20,000 studies, concluded that glyphosate is safe and does not cause cancer. The only danger they found was that glyphosate “causes serious eye damage”.
Why is this significant? The EU has banned glyphosate in many applications, on a purely political basis, but the average person used this as “evidence” that glyphosate was harmful and caused cancer. It is good to see that the EU scientific community has finally done a proper review. Hopefully, governments will now catch up with the science.
Glyphosate (Roundup) and GMO
A common argument agaisnt GMO plants is that it encourages the use of Roundup. These two issues are unrelated to one another.
Yes, there are some Roundup-ready GMO crops. But the majority of GMO plants have nothing to do with Roundup and they are not Roundup-ready. See GMO Myths – Understand the Truth About GMO Plants for more details.
You can be against Roundup and be for GMO.
Glyphosate (Roundup) Found in Drinking Water and Babies Milk
Studies have found glyphosate in drinking water and in mothers breast milk. The headlines claimed that this was a huge problem, but when you look at the details you realize that it’s a non-issue.
It’s all about the dose.
Our scientific instruments are so good these days that we can find just about any chemical in water and milk. I reviewed the report that found glyphosate in Spain’s drinking water and calculated that you would need to drink the equivalent of 1,000,000,000 bottles of beer, on a daily basis, in order to reach an unsafe level.
The levels found in the environment and in mothers milk are extremely low and of no health concern.
Glyphosate (Roundup) and Chronic Diseases
Some claim that glyphosate causes all kinds of diseases including, diabetes, neuropathies, obesity, asthma, infections, osteoporosis, infertility, birth defects and non-celiac gluten sensitivity. Many of these claims have been made by Samsel and Seneff.
Anyone who has followed the Roundup debate will recognize the name of Dr. Stephanie Seneff. She has made numerous claims about glyphosate which are quickly discounted by the scientific community “as outrageous use of science”. Dr. Seneff is a computer programmer with no experience in chemistry, plant science or health science. Her most recent claim is that glyphosate is a contributing factor of COVID-19.
Unfortunately, the general public eats up her publicity stunts.
A recent review of the claim that glyphosate causes chronic diseases found no support for the claim and went on to say “Our critical analysis of the commentaries published by Samsel and Seneff reveals that their conclusions are not substantiated by experimental evidence but are based on a type of failed logic known as syllogism fallacies. As Nobel Prize-winning theoretical physicist Richard Feynman famously said, “It doesn’t matter how beautiful your theory is, it doesn’t matter how smart you are. If it doesn’t agree with experiment, it’s wrong.””
Glyphosate (Roundup) and Soil Microbes
It is commonly believed that glyphosate harms soil microbes. When glyphosate was added to soil it was found that “it was rapidly degraded by microbes, even at high application rates, without adversely affecting microbial activity.”
Glyphosate (Roundup) and Gut Bacteria
Numerous recent reports in the media and online claim that science has demonstrated glyphosate affects our gut bacteria, and if true could have serious health implications.
One of the reasons glyphosate is so safe is that it only affects a well understood biochemical pathway called shikimate, which is found in plants but not animals. This is the reason it is not toxic to animals. The shikimate pathway is found in some bacteria that live in our gut.
A recent study claims to have shown that glyphosate can affect these bacteria.
Marc Brazeau is the editor of Food and Farm Discussion Lab and is the Genetic Literacy project’s senior contributing writer. He has done a thorough review of the report claiming a link between glyphosate and gut bacteria and found that the data did not support the conclusions.
The study itself does say, “more studies will be needed to ascertain if there are health implications arising from glyphosate inhibition of the shikimate pathway in the gut microbiome”. The study did not reach any conclusions about glyphosates effect on our health, even though the news reported it with sensational headlines.
Another study found that even levels 50 times larger than the Accepted Daily Intake (ADI) set by European food safety agencies had very limited effect on gut bacteria.
Glyphosate (Roundup) and Bees
A study sprayed honeybees with a normal concentration of glyphosate and found no harm to the bees.
Some studies have looked at bee behavior after exposure to glyphosate, and have reported some learning disabilities in bees. The number of bees studied was very low, and 1/4 of those were lost during the study. Other studies have looked at exposure to very high levels of glyphosate.
Bees certainly have environmental and pest problems, but glyphosate has not been shown to be one of them.
Facts About Glyphosate
Here are some important facts about glyphosate.
- our skins absorb very little
- it undergoes very little metabolism in the body and is mostly excreted
- it has a very low toxicity; the oral LD50 in rats is 4320 mg/kg, significantly less than vinegar
- it quickly adsorbs to soil and becomes inactive
- it has a soil half-life of 50 days, which is short for a pesticide
- plant uptake from soil is minimal
Not Enough Testing!
The anti-Roundup movement is quick to claim that there has not been enough testing, and that the existing testing was done by labs hired by Monsanto. That is nonsense. Over the last 45 years there have been thousands of studies by labs all around the world.
At some point you have to accept the results.
For those who aren’t familiar with toxicology, the author is quite right that the dose is a critical component. Quite literally, everything can cause harm under the right conditions, and this is why we do not assess the acute and chronic toxicity to determine if something is safe; we assess it to show when something causes harm.
The current gold standards for this are the OECD Guidelines for the Testing of Chemicals (Section 400), and to date glyphosate has been assessed many, many times.
For instance, one of the more comprehensive methods for determining chronic effects is OECD-453, a combined carcinogenicity and chronic toxicity study examining oral exposire. Between 1990-2009, 7 studies that were fully compliant have been conducted (for review see Griem et al, 2015).
In every case, they do not show any significant increase in negative health effects until the dose was far, far above the current limit…which makes sense as we used these studies to determine that limit in the first place.
It should be noted that it wasn’t just Monsanto running these tests, nor were they the product of the same researchers. The studies came from industry, academic, and government labs from the US, UK, Italy, Poland, India, and Japan, yet they all managed to obtain similar results.
This replicatability is a key part of the scientific method.
Out of all the compliant testing to date, the Lowest Observed Adverse Effect Limit (LOAEL, the lowest dose whee we do see a significant increase in adverse effects) is 175mg/kg/day, and the No Observed Adverse Effect Limit (NOAEL, the highest dose where we see no increase in negative health effects is 100mg/kg/day.
Care 5o guess how many studies that meet the standards in toxicology to test for causal effects have shown harm below this point, let alone the ADI, which is 1mg/kg/day in the US and Canada?
None!
Even though the anti-biotech groups have had decades to perform a compliant study, we see nothing of the sort.
As the methods are open access, this begs the question why they cannot meet the same standards that we have across the entire field.
As to the full formulation, the main factor are the surfactants…soap by any other name, and we do not recommend drinking dish soap.
Oh, and it should be pointed out that individuals like Damsel and Semeff love to toss out hypotheses…but they never test them to determine if they are correct.
This isn’t a joke, and simply reading over the materials and methods shows this. Semeff datamines papers, takes the bits she likes, wraps it up into a hypothesis blaming glyphosate for every human I’ll, but then…nothing.
Thanks Gregory – useful to know.
Thank you for this slice of sanity. IMHO, social distancing should include social media distancing. Shut down the clatter-traps! Stay healthy and bloom on!
We all have different views about safety. I only have 10-years of gardening experience but like so many people of my generation, I also have an increased sensitivity to certain chemicals and certain surfactants. The reasons/mechanisms for this are still largely unknown. I appreciate that you have a background in chemistry and biochemistry, but are you up-to-date with the recent commentary from the International Agency for Research on Cancer (IARC) about the potential epigenetic impacts of certain environmental chemicals?
Like some of your other readers, I have also read that the surfactants in glyphosate are more toxic than glyphosate itself.
It seems obvious to me that we don’t know enough about how some of these herbicides/pesticides and industrial products interact, and whether there is a risk of altered gene expression in humans.
Naturally I’m eager to keep an eye on any future research because of my own personal experience. Like you, I do always want to see the facts rather than listen to the hype – but when research is lacking then I’m happy to remain cautious. If you had experienced chemical sensitivities yourself then I suspect you would take a more cautious view also.
I guess you think everyone who stands against your product has imagined all this in their head that roundup causes cancer and only doing this for money! The truth of the matter is this product has made your company billions of dollars and your going fight against anyone who takes a stand against roundup chemical that it causes cancer! Ask yourself one question! In all the history of chemicals that is ever made has it be proven that any of them is really safe? Everyone who has ever used them would say no. Why? Cause chemicals are a product that is made to destroy for whatever reason it’s made and if breath in or gotten on the skin only those who experience the use of these chemicals knows how dangerous it is to themselves after they get sick!
1) It is not my product.
2) I don’t work for any company.
3) I make no money on writing these posts, except that you might buy one of my books.
You do not understand chemicals.
“Has any chemical been proven to be safe?” Yes glyphosate. Water. Milk. vitamins. proteins. etc, the list is a long one, provided you understand the dose. Even water can kill you.
“Chemicals are made to destroy” – so you think that all drugs are made to destroy us? All the food we eat are chemicals – the aim of food processing is not to kill us.
Who paid you to write this? Roundup has been paying for fake research for decades, if it’s so safe take drink. I have been told by nursery people that it’s so safe you could drink it.
Nobody. And it is safe enough to drink – just check the facts.
Thank you, Robert, for another dose of sanity in a clearly nuts world. As evidenced by the first poster, so many people want to ignore reality, and behave according to myths and legends of the day. Not that I blame the individual for this. Organizations have all of our heads on backwards. In this case, it is coming from a lot of nonprofits, whom people trust–they still do a lot of fear mongering towards it. Look at the spin that the U.S. Right to Know organization does on it. The most compelling “evidence” it can link to for the connection of it to cancer is a weak statement by an Obstetrics organization talking about things its members don’t specialize in (aka nothing about reproductive health), but USRTK throws lots of stats to make it seem very dangerous.
Anyway, thanks for doing your part, and being so prolific! I love getting your posts in my inbox and it has been particularly pleasant during the strangeness and isolation due to the pandemic.
I did read some articles in the media at some stage that claimed that Roundup (= Glyphosate + Surfactant) was more of a health concern than Glyphosate alone. And further that much of the research on toxicity/carcinogicity was done on Glyphosate alone. The Surfactant is included in Roundup to make sure that the Glyphosate wets the leaves well and absorbs well into the plant. It may also result in Glyphosate being better absorbed by us.
So I haven’t made any effort to read the literature but it would be interesting to know how much research has been done on the Glyphosate + Surfactant product.
Great article by the way – thoroughly agree that this product has been well and truly maligned by folk who typically offer no suggestion on what they expect farmers to do if the folk succeed in getting Glyphosate banned. I worry that farmers may be forced to use much more hazardous chemicals like paraquat and diquat.
Cheers.
You are correct, the surfactant is probably more of a concern than glyphosate. But surfactants are considered safe as well, to the extent that companies don’t even have to list all of the surfactants they use. Soaps are surfactants.
Including the surfactant in the discussion was simply a way to move the goalposts. Glyphosate is safe at levels used and at residual levels. All major health organizations conclude that, even the W.H.O..
At residue levels the surfactant or glyphosate have no interaction. You have to have a threshold level for a surfactant to do its job. At residue levels they are just two rare molecules that move independently through the body.
Thank yoou for this excellent, timely article!
Thank you for your report. I find it so frustrating when people hear only a headline (usually a false one!) and think that is the whole truth.
Excellent information as always! Thank you so much Mr. Pavlis!
Great article. I was one of the first person to use RU in Ct. My cousin was a chemist at Monsanto and he brought us a gallon to test. Didn’t even have labels at that time. People the think Monsanto is the villain really don’t understand farming. I have degrees in Soils and also plant pathology and I have no worries with RU. Great safe tool.
Neat! Do you remember what year that was?
People used to use Radium under the belief it was safe when it was first introduced. I assume there were people who said the same thing about DDT. With your degrees, what do you make of this statement?
“We observed a human cell endocrine disruption from 0.5 ppm on the androgen receptor in MDA-MB453-kb2 cells…”? https://pubmed.ncbi.nlm.nih.gov/19539684/
Even the most qualified people know less than first year students, if they haven’t read the current literature and the students have.
Yes people used Radium until further testing was done to show at higher levels it is a problem. With glyphosate we now have over 50 years of testing and 20,000 studies – we are not in the early stages of using this product.
You link is a test in a petri dish, applying glyphosate directly to cells. When glyphosate is ingested, almost none is absorbed into the body – it just flushes through. This kind of testing needs to be done with real world doses. Even this study concludes with “A real cell impact of glyphosate-based herbicides residues in food, feed or in the environment has thus to be considered”. It does not conclude that there is any danger.
Even the EU has now come out and stated that they consider glyphosate to be safe.