Reasons for Concern: Glyphosate Risks to Human Health

Glyphosate (N-phosphonomethylglycine) is the most heavily used chemical weed killer in food and agricultural production in human history. Since glyphosate-based herbicides were first introduced in 1974, glyphosate use has skyrocketed more than 300-fold, leading to more than 3.5 billion pounds being sold in the United States during this time. In the past decade alone, more than 2.4 billion pounds have been applied to farmers’ fields – or 67% of all glyphosate ever sold in the U.S – as a result of the widespread adoption of genetically engineered crops. As the main active ingredient in the bestselling herbicide Roundup ®, each year more than 300 million pounds of glyphosate-based herbicides are sprayed on food crops, lawns and home gardens across the country.

Glyphosate damage by the Numbers (in parts per billion)

While regulators at the EPA determined in the 1990s that 1.75 mg per kilogram of bodyweight per day is the safe allowable daily intake level in the U.S., the EPA’s own website lists glyphosate under “Regulated Drinking Water Contaminants.” The EPA warns people that long-term exposure to glyphosate at only 700 ppb can cause “problems with their kidneys or reproductive difficulties” and states that drinking water exposure exists due to “Runoff from herbicide use.”


Graph Source: Mesnage, R., et al. “Potential Toxic Effects of Glyphosate and Its Commercial Formulations below Regulatory Limits.” Food and Chemical Toxicology, vol. 84, 2015, pp. 133–153., doi:10.1016/j.fct.2015.08.012.


Why should you be concerned?

Glyphosate Poses Several Possible Risks to Human Health:

  1. Cancer

Despite repeated claims from the biotech industry that glyphosate is safe, even “safer than table salt,” an increasing number of independent peer-reviewed studies are finding troubling links to a growing number of diseases in humans, including cancer. In March 2015, leading cancer experts from the World Health Organization’s International Agency for Research on Cancer (IARC) declared that glyphosate is a “probable human carcinogen.” IARC reached its decision based on the research of 17 top cancer experts from 11 countries, who met to assess the carcinogenicity of 5 pesticides. The IARC review of glyphosate has led to the European Parliament calling for a complete ban on non-commercial public use of glyphosate and serious restrictions on agricultural use.

Multiple class action lawsuits and a wrongful death lawsuit have been filed in the U.S. against Monsanto (now Bayer), based on the finding that glyphosate is a probable cancer-causing agent used with regularity by farmers, farm workers, pesticide applicators and others exposed to the chemical through routine use. There are specific concerns over the following cancers:

  • Non-Hodgkin’s Lymphoma
  • Bone Cancer
  • Colon Cancer
  • Kidney Cancer
  • Liver Cancer
  • Melanoma
  • Pancreatic Cancer
  • Thyroid Cancer


  1. Endocrine Disruption

A growing body of peer-reviewed scientific evidence shows that glyphosate also acts as an endocrine disruptor at levels that the human population is routinely exposed to through the consumption of GMO foods and foods that have been sprayed with glyphosate as a pre-harvest drying agent.

According to a 2013 study published in Food and Chemical Toxicology – an internationally renowned journal, that publishes original research articles and reviews on toxic effects, in animals and humans, of natural or synthetic chemicals occurring in the human environment – Glyphosate induces human breast cancer cells growth via estrogen receptors.

Glyphosate was found to be an “endocrine-disruptor”, meaning it has detrimental effects on the body’s hormones, specifically on estrogen. High levels of estrogen is a known factor in hormone-dependent breast cancer.  The research indicated that even low and environmentally relevant concentrations of glyphosate possessed estrogenic activity. The additional concern with soy-based foods: Glyphosate-based herbicides are widely used for soybean cultivation, and the research results also found that there was an additive estrogenic effect between glyphosate and genistein, a phytoestrogen in soybeans.

  1. Binding of essential nutrients

Glyphosate binds, or chelates, important nutrients such as iron, manganese, zinc, and boron in the soil, preventing plants from absorbing these nutrients via their root system, which leads to nutrient-depleted food crops and soil as a result. This has health implications for humans, livestock and pets that eat glyphosate tolerant GMO crops, as it impacts nutritional status.

  1. Antibiotic

Glyphosate is also patented as an antibiotic, or biocide, meaning that beyond its use as an herbicide to kill weeds, it may have a significant harmful effect on the human microbiome and the ecosystems of farm animals by killing beneficial microorganisms in the gut.

Concerns continue to grow from independent scientists and medical professionals regarding glyphosate’s antimicrobial effects on human and animal health. Evidence suggests that glyphosate can alter the balance of the gastrointestinal microbiome, or beneficial gut bacteria, and create a harmful imbalance in human and animal gut flora while increasing pathogenic species that can lead to multiple negative health outcomes, including food intolerances ( like gluten) and irritable bowel syndrome. In the first such research in the world, a team from the University of Canterbury in New Zealand found in 2015 that commonly used herbicides, including Roundup (glyphosate-based), can cause bacteria to become resistant to antibiotics.  Not surprisingly, this study was picked up by U.S. cardiologist Dr. William Davies, the New York Times bestselling author of Wheat Belly, which details the alarming rise in gluten sensitivity and intolerance in the American public, who noted:

“Animal model data demonstrates that glyphosate selectively kills beneficial bacteria, such as Enterococcus faecalis, Enterococcus faecium, Bacillus badius, Bifidobacterium adolescentis and Lactobacillus species, while allowing the proliferation of undesirable, even disease-causing, species such as Salmonella enteritidis, Salmonella gallinarum, Salmonella typhimurium, Clostridium perfringens and Clostridium botulinum.”

Does an Organic Diet Matter?

Just one week of eating an organic diet can reduces pesticide exposures by 90%.

Since GMOs and Roundup are both prohibited from organic production, the simplest way to avoid glyphosate contamination in food and to reduce exposures to synthetic pesticides is to eat organic food. A 2014 study published in the Journal of Environmental Research confirmed that families eating an organic diet for as little as a week removed more than 90% of the pesticides from their system, as detected through urine tests. According to this independent study, “the average person is exposed to 10 to 13 pesticide residues each day from food, beverages and drinking water.


Glyphosate in foods that parents feed their children








































Limit of Quantitation: 5 ppb
*These samples exhibit very low recovery and/or response. The above amounts found are rough estimates at best and may not represent an accurate representation of the sample.
** Widespread contamination in food supply — even organic farmers are having their crops/ our food contaminated.

Data in Chart above sourced from: Food Democracy Now! (2016). Glyphosate: Unsafe on Any Plate. (includes 114 references)


Thongprakaisang, Siriporn, et al. “Glyphosate Induces Human Breast Cancer Cells Growth via Estrogen Receptors.” Food and Chemical Toxicology, vol. 59, 2013, pp. 129–136., doi:10.1016/j.fct.2013.05.057.

Mesnage, R., et al. “Potential Toxic Effects of Glyphosate and Its Commercial Formulations below Regulatory Limits.” Food and Chemical Toxicology, vol. 84, 2015, pp. 133–153., doi:10.1016/j.fct.2015.08.012.

Food Democracy Now! (2016). Glyphosate: Unsafe on Any Plate. (includes 114 references)