Glyphosate is the “so-called” active chemical ingredient in Roundup herbicide as well as many other name brand glyphosate-based weedkillers. While we are focused here on glyphosate, it should be noted that according to studies, the full formula herbicide may be up to 1,000 times more toxic than glyphosate alone. (Mesnage 2013, Defarge 2016) What chemical manufacturers label as “inert ingredients” or adjuvants have been found to magnify the toxicity of glyphosate. This is most disturbing because the EPA approval process for pesticides requires pre-market safety/toxicity studies that focus only on the so-called active chemical and ignore the harms from other ingredients. No testing of the full formula herbicide is required.

Glyphosate based herbicides are the most widely used in the world and their use has increased exponentially with the introduction of Genetically Modified (GM) crops. According to the most recent USDA data, in 2016, 94% of soybean and 89% of corn acreage in the U.S. were planted with GM herbicide tolerant varieties. (United States Department of Agriculture Economic Research Service 2016) Of the sugar beet acreage in the U.S., over 99% is GM herbicide tolerant. (Fernandez-Cornejo 2016) The majority of herbicide tolerant crops are engineered to be sprayed with a glyphosate based herbicide, sometimes in combination with other herbicides such as dicamba or 2,4D.

Glyphosate can potentially drift from the site of application, moving from one field to another and damaging crops not genetically modified to tolerate the herbicide. (Reddy 2010) Drift can cause non-GMO crops to suffer from lower yields or total crop loss. This risk and fear of damage to non-GMO crops from pesticide drift has contributed to the increase in the use of genetically modified crops. Farmers are choosing to grow GMO crops instead of non-GMO crops to protect themselves from loss of profits.

Due to years of repeated spraying with glyphosate based herbicides, weeds have developed resistance and rendered these herbicides less effective, causing farmers to spray even more glyphosate. (Benbrook 2016) Since the introduction of GMO crops, glyphosate use has increased almost 15-fold (Benbrook 2016). In response to this dramatic rise in glyphosate use and the resulting increase in glyphosate residue in crops and food, the agrichemical industry has petitioned the Environmental Protection Agency (EPA) to incrementally increase the allowable “safe” levels of glyphosate residues in crops and food. This is despite credible scientific evidence pointing to the need to lower the acceptable daily intake for glyphosate. (Myers 2016, Cuhra 2016, Ibrahim 2016) The allowable levels of glyphosate in food were deemed “safe” not because there was scientific evidence proving their safety, but to accommodate farmers who were overusing the herbicide.

Estimated Agricultural Use for Glyphosate in the United States from 1992 – 2011 animated (2 minutes).
Source: U.S. Geological Survey (USGS) NAWQA Program Pesticide National Synthesis Project


There are three separate patents on glyphosate, each for a different use.

Glyphosate was first patented in 1964 by Stauffer Chemical as a metal chelator that was used to clean or descale commercial boilers and pipes (United States Patent 3,160,632). Glyphosate binds to and removes minerals such as manganese, zinc and cobalt that are vital to human and animal health (Johal 2009).

A second patent was filed in 1974 by Monsanto as an herbicide (United States Patent 3,799,758). Monsanto claims that glyphosate, which kills plants by disrupting the shikimate pathway, has no effect on humans because the shikimate pathway is not present in mammals. However, several studies now suggest harm to mammals from glyphosate based herbicides through a variety of different mechanisms (Myers 2016, Ibrahim 2016a).

In 2003, Monsanto filed for a third patent on glyphosate as a parasitic control type antimicrobial, or antibiotic (United States Patent 7,771,736). This patent was granted in 2010. It is proposed that glyphosate be used as a treatment for microbial infections and parasitic control of various diseases such as malaria. The microbiota of humans and animals, however, plays an important role in their immune systems (Purchiaroni 2013). Glyphosate based herbicides may act as an antibiotic, harming beneficial animal gut bacteria (Ackermann 2014, Shehata 2013, Schrödl 2014).


In the most recent USDA 2013 Annual Pesticide Data Program Report on food testing for pesticide residues, the USDA concluded, based on the results of their testing, that our food supply contains safe levels of pesticides. One big problem – the USDA report claims they didn’t test for glyphosate, which, as previously noted, is the most widely used herbicide in conventional agriculture. This is surprising, given that farmers are reporting increased usage resulting from the rise in herbicide tolerant weeds and given the fact that the EPA has incrementally increased the allowable residue tolerance levels on various food crops at the request of the chemical industry, without scientific basis. The USDA’s report “Genetically Engineered Crops in the United States” (USDA Economic Research Service 2014) disclosed that the amount of glyphosate based herbicide applied to GM corn crops increased from approximately 1.5 pounds per planted acre in both 2001 and 2005 to more than 2.0 pounds per planted acre in 2010.

While glyphosate goes hand in hand with GM agriculture, many people are unaware that glyphosate is also used on many non-GMO crops as a desiccant, ripening or drying agent. When these crops (such as wheat, barley, sugar cane, oats, lentils, beans, edible peas and chickpeas, sunflowers, potatoes and cantaloupe) are nearly mature, farmers are allowed to spray glyphosate herbicides on the crop to kill the plant which causes it to dry down for a quicker harvest.

Glyphosate and aminomethylphosphonic acid (AMPA), a breakdown metabolite of glyphosate, have routinely been detected in food (Bohn 2013) and glyphosate residues may remain on foods several months after spraying (Cox 1995). Glyphosate and AMPA have previously been detected in air, sources of drinking water, and precipitation (Majewski 2014, Battaglin 2014).  AMPA is considered to be more persistent than glyphosate in the environment (Cox 1995).


There is a growing body of scientific evidence that links glyphosate to health and environmental harm.

Health Impacts

The International Agency for Research on Cancer (IARC), the specialized cancer agency of the World Health Organization (WHO), concluded that there is sufficient evidence of glyphosate’s carcinogenicity in experimental animals and classified glyphosate as probably carcinogenic to humans (International Agency for Research on Cancer 2015). A jury in U.S. federal court in California delivered a $289 million verdict against Monsanto, the primary manufacturer of glyphosate-based herbicides, on behalf of a school groundskeeper who developed non-Hodgkins lymphoma after repeated exposure to Monsanto’s Roundup herbicide. The verdict stated Monsanto acted with malice failing to warn of the risk of developing non-Hodgkin’s lymphoma, a form of cancer, from exposure to glyphosate. Currently about 8,700 other people diagnosed with Non-Hodgkin’s Lymphoma after being exposed to a glyphosate-based herbicide are also suing Monsanto. (CBS/AP 2018, Marketwatch 9/5/2018) Lawsuits will likely continue against both the manufacturer and companies or communities that have exposed people to glyphosate-based herbicides.

In an vitro study, AMPA (aminomethylphosphonic acid), a breakdown metabolite of glyphosate, was observed to be more toxic than glyphosate on human embryonic kidney and placental cells and the combination of glyphosate and AMPA was more toxic than glyphosate or AMPA alone (Benachour 2008).

Studies suggest glyphosate based herbicides at relatively low levels may be endocrine disruptors (Gasnier 2009, Myers 2016) with the ability to potentially reduce testosterone levels (Clair 2012, Abarikwu 2015), impair sperm quality (Abarikwu 2015, Owagboriaye 2017), or cause disturbances in the reproductive development of rodents when they were exposed during puberty (Romano 2010). Studies have also reported kidney and liver damage in rodents, including the potential for non-alcoholic fatty liver disease, in some cases at glyphosate levels as low as .05 parts per billion. (Abarikwu 2015, Benedetti 2004, Seralini 2014, Mesnage 2015, Mesnage 2017). Other studies have observed intestine smooth muscle activity disturbances (Chlopecka 2014, Chłopecka 2017). In one study the children of rats exposed to glyphosate based herbicide had altered gut microbiota in early development.

Along with an increase in glyphosate use on crops there has been a 500% average increase in the level of glyphosate found in human urine. (Mills 2017) One study found higher urinary glyphosate levels in pregnant women was associated with a shortened gestational length which is associated with a reduction in lifetime cognitive achievement (Parvez 2018). Another study observed humans that were chronically ill had significantly higher glyphosate residues in their urine than their healthy counterparts (Kruger 2014).

Environmental Impacts

The environment is adversely impacted by the use of glyphosate-based herbicides, such as Roundup. These adverse effects occur at environmentally relevant levels such as the levels much lower than those used for landscaping and agricultural purposes. In both freshwater and saltwater aquatic ecosystems glyphosate-based herbicides have adverse effects. Glyphosate based herbicides are a contributing factor in harmful cyanobacteria blooms (Zhang 2016). Aquatic species that serve as food for fish and amphibians, such as Daphnia ambigua, have increased mortality due to exposure to low doses of glyphosate-based herbicides(Glyphosate Studies). There is overwhelming evidence that various fish and amphibian species are also adversely impacted by low dose exposure to glyphosate-based herbicides (Glyphosate Studies). Native aquatic plants grown around lakes support beneficial bacteria that consume debris and potentially harmful organisms while increasing water clarity and providing habitat to fish and other water life. However, these aquatic plants and the beneficial bacteria they support are often injured or killed by glyphosate-based herbicides. Glyphosate-based herbicides are also harmful to various species of crustaceans and mollusks (Glyphosate Studies).

In and around agricultural lands, glyphosate based herbicides have been a major contributor in the reduction of the monarch butterfly, has been shown to alter bee behavior and adversely impact amphibians. Glyphosate based herbicides can also harm beneficial insects such as the green lacewig and two spotted ladybug. (Glyphosate Studies) Other beneficial organisms such as several spiders and earthworms are also adversely impacted by glyphosate based herbicide use. (Glyphosate Studies)


Pediatrician Michelle Perro offers this insight into the impact of glyphosate on children’s health:

“Digestive health is rapidly declining in children. If children eat conventionally grown food, they will potentially be eating glyphosate, pesticide adjuvants and GMOs as documented by these laboratory tests. What is happening to our children is several-fold: Alteration of their microbiome with subsequent issues of detoxification, production of vitamins and repair of their intestinal lining due to the anti-microbial effects of glyphosate. Additionally, they are mineral-deficient because of the chelation of glyphosate. There is laboratory evidence of zinc deficiency, for example, which then leads to immunological weakness/impairment since zinc is an important co-factor in immune system function.

Children are also experiencing an exponential increase in allergies which can be linked to lack of recognition of rogue proteins produced by genetically altered proteins in foods. This can subsequently cause an activation of their immune systems and production of antibodies against foods; the body is seeing the foods as foreign invaders and producing an immune response.

The bioaccumulation effects of glyphosate have not been addressed in children and the standards of safety are arbitrary and not based on any clinical evidence.”

Overwhelming scientific evidence documents the potential harms of glyphosate.

You can find a comprehensive list of glyphosate studies HERE.



**Michelle Perro, MD, has been a practicing pediatrician for 32 years, presently working at the Institute for Health and Healing in SF, CA in the department of Integrative Medicine. She has lectured both nationally and internationally on the topics of pesticides and GMOs and the effect on children’s health. She is currently working on her book concerning the rising incidence of childhood illness and the effects from various environmental toxins.

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Glyphosate Studies

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Parvez, S., Gerona, R.R., Proctor, C., Friesen, M., Ashby, J.L., Reiter, J.L., Lui, Z. and Winchester, P.D., 2018. Glyphosate exposure in pregnancy and shortened gestational length: a prospective Indiana birth cohort study. Environmental Health, 17(1), p.23.

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