Glyphosate is found in hundreds of herbicide products, residues in common foods like oats, wheat, corn, and soybeans, and trace amounts in some drinking water supplies. It is the most widely used herbicide in the world, applied across roughly 300 million acres of U.S. cropland each year. Because of how broadly it’s used in agriculture, landscaping, and home gardening, most people encounter it through the food they eat rather than direct contact with the chemical itself.
Crops With the Highest Glyphosate Use
Soybeans and field corn account for the largest share of glyphosate application in the United States. According to EPA usage data from 2014 to 2018, field corn alone received about 90 million pounds of glyphosate per year, spread across 93 million acres. Soybeans received a comparable or even larger amount. Both crops are overwhelmingly grown as genetically modified varieties engineered to survive direct glyphosate spraying, which means the herbicide is applied while the plants are actively growing.
Wheat is another major source, though for a different reason. Winter wheat receives about 7 million pounds per year, and spring wheat about 5.4 million pounds. Wheat isn’t genetically modified to tolerate glyphosate. Instead, farmers sometimes spray it just before harvest as a drying agent, a practice called desiccation. University of Minnesota Extension notes that glyphosate applied at the hard dough stage can hasten crop dry-down in adverse conditions. This late-season application is one reason wheat-based foods can carry detectable residues.
Oats follow a similar pattern. They receive glyphosate as a pre-harvest drying treatment, and because oats aren’t genetically modified either, the spray lands on the grain close to harvest time. Other crops treated with glyphosate include almonds, sugar beets, canola, cotton, sorghum, and various fruits and vegetables where it’s used to clear weeds between rows rather than sprayed on the crop itself.
Processed Foods, Especially Oat Products
Oat-based breakfast cereals and snack bars have drawn the most attention for glyphosate residues. Testing by the Environmental Working Group found that in 2018, some samples of Quaker Oatmeal Squares contained nearly 3,000 parts per billion (ppb) of glyphosate. By 2023, levels in the same product line had dropped significantly, ranging from 20 ppb to under 500 ppb. EWG uses a benchmark of 160 ppb for what it considers a health-protective limit, though U.S. regulatory tolerances are set much higher.
Beyond oat cereals, glyphosate residues show up in a wide range of grain-based processed foods: bread, crackers, pasta, granola bars, and beer. Any product made with conventionally grown wheat, oats, corn, or soy has the potential to contain trace amounts. The levels vary widely depending on how the crop was grown, whether pre-harvest desiccation was used, and how much processing the grain underwent.
Meat, Dairy, and Eggs
Livestock eat enormous quantities of corn and soy feed that may contain glyphosate, which raises an obvious question about whether residues carry through into animal products. The FDA tested 879 samples of corn, soybeans, milk, and eggs during 2016 and 2017 specifically for glyphosate. No residues were found in any milk or egg samples, and no samples in any of the four categories violated federal residue limits. Glyphosate doesn’t accumulate in animal tissue the way some other chemicals do. It’s water-soluble and excreted relatively quickly, which is why it rarely shows up in meat or dairy at meaningful levels.
Drinking Water
Glyphosate can wash off treated fields into nearby streams and rivers, but it typically doesn’t persist in water at high concentrations. Minnesota Department of Health data offers a useful snapshot: the highest level detected in surface water was 42.8 micrograms per liter, and the state’s groundwater monitoring efforts have not yet detected glyphosate in groundwater at all. In public drinking water systems across Minnesota, glyphosate has been found only four times since 1993, at levels between 1.1 and 39 micrograms per liter. The federal maximum contaminant level for glyphosate in drinking water is 700 micrograms per liter, so detected levels have been far below that threshold. Municipal water treatment generally reduces glyphosate concentrations further before water reaches your tap.
Weed Killers for Homes and Public Spaces
Roundup is the most recognizable glyphosate product, but it’s far from the only one. Dozens of consumer herbicides sold at garden centers and hardware stores contain glyphosate as their active ingredient, marketed under names like Rodeo, Kleenup, and various store brands. These are sold as ready-to-spray formulas for driveways, garden beds, fence lines, and patios.
Glyphosate has also been widely used in public spaces: parks, golf courses, roadsides, school grounds, and utility rights-of-way. Some municipalities have started phasing it out. The city of Louisville, Colorado, for example, discontinued glyphosate use in city parks and open spaces in 2020, though it made an exception for its golf course. Similar bans or restrictions have been adopted by cities and counties across the country, but glyphosate remains in use in the majority of U.S. public land management programs.
How Much Ends Up in Your Body
CDC biomonitoring data from the National Health and Nutrition Examination Survey (2013-2014) confirmed that glyphosate is detectable in the urine of most Americans. The geometric mean concentration across the general population was 0.41 micrograms per liter. Children aged 6 to 11 had slightly higher average levels (0.52 micrograms per liter) than adults over 20 (0.39 micrograms per liter), likely reflecting differences in body weight relative to food intake. At the 95th percentile, the highest-exposed individuals had urinary concentrations around 1.58 micrograms per liter.
These numbers confirm widespread low-level exposure but don’t, on their own, tell you whether that exposure is harmful. The health debate centers on a disagreement between major agencies. In 2015, the International Agency for Research on Cancer classified glyphosate as “probably carcinogenic to humans,” based on limited evidence of cancer in people and sufficient evidence in animal studies. The U.S. EPA reached a different conclusion, finding that glyphosate is “not likely to be carcinogenic to humans” at levels people typically encounter. This split has not been fully resolved, and it drives much of the ongoing controversy around glyphosate in food and the environment.
How to Reduce Your Exposure
If you want to lower the amount of glyphosate in your diet, the most effective step is choosing organic versions of the foods most likely to carry residues. Organic oats, wheat flour, and soy products are produced without glyphosate. This matters most for oat-based cereals and granola, which have consistently shown some of the highest residue levels in testing.
For your yard, glyphosate-free weed control options include vinegar-based herbicides, manual weeding, mulching, and products based on other active ingredients like pelargonic acid. These alternatives vary in effectiveness, but they eliminate one route of direct skin and inhalation exposure. Washing produce removes surface pesticide residues to some degree, though glyphosate absorbed into grain kernels before harvest cannot be washed off.