Pesticides on U.S. Soybeans: Rising Herbicide Use, Seed Treatments, Residues, and What It Means for Soy Foods

Soybeans are one of America’s largest crops, planted on more than 80 million acres a year and used for animal feed, cooking oil, and foods from tofu and soy milk to the soy protein and lecithin found in countless processed products. Over the past two decades, reports have periodically noted that soybean farmers were spending dramatically more on pesticides than a few years earlier, raising questions about what is sprayed on the crop and what ends up in food.

Those reports reflected a real trend. As weeds evolved resistance to glyphosate, the herbicide that genetically engineered soybeans were designed to tolerate, farmers added more herbicides, and insecticide seed treatments became nearly routine. This article examines current pesticide use on U.S. soybeans, why it has grown, what residues have been found in soybeans, whether soy foods are safe and healthy, and how consumers can reduce exposure.

How much pesticide is used on soybeans, and is soy safe to eat? U.S. soybeans receive large amounts of herbicide, especially glyphosate, because most are genetically engineered to tolerate it; in 2023 growers applied roughly 89 million kilograms of herbicides. Glyphosate residues appear in GM soybeans but not conventional or organic ones. Despite this, soy itself is a healthy, protein-rich food, and common fears about soy and hormones are not supported by evidence.

How Much Pesticide Is Used on Soybeans?

U.S. soybeans receive large quantities of herbicide: 2023 government data show roughly 89 million kilograms applied, worth billions of dollars, driven mainly by glyphosate on herbicide-tolerant GM soybeans. USDA’s National Agricultural Statistics Service surveyed soybean growers in 2023 in 19 states covering 96.3 percent of the 83.6 million acres planted that year. Herbicides were applied to 96 percent of planted acres and insecticides to 21 percent. A 2025 analysis in Weed Technology by Mandeep Singh and Amit Jhala used the survey data to estimate that about 89.1 million kilograms of herbicides were applied to U.S. soybeans in 2023. Glyphosate in various salt forms was the most widely applied herbicide, followed by 2,4-D, with about 15.9 million kilograms, and glufosinate, with about 4.4 million kilograms. Using average retail prices, the authors estimated that herbicides alone, excluding adjuvants and application costs, cost soybean growers about $4.1 billion.

Why Has Herbicide Use on Soy Increased?

Herbicide use grew as most soybeans became genetically engineered to tolerate glyphosate, encouraging reliance on it, and rose further as glyphosate-resistant weeds spread, prompting more and additional herbicides. Glyphosate-tolerant soybeans, introduced in 1996, made weed control simple: farmers could spray glyphosate over the crop and kill most weeds. Adoption soared, and a 2016 analysis in Environmental Sciences Europe by Charles Benbrook found that glyphosate became the most heavily used herbicide in history, with use rising almost fifteenfold globally after herbicide-tolerant crops were introduced. Heavy reliance on one herbicide selected for resistant weeds. A 2018 review in Pest Management Science by Ian Heap and Stephen Duke counted 38 glyphosate-resistant weed species worldwide, with the greatest impact in herbicide-tolerant crop systems in the Americas. Farmers responded by adding herbicides with other modes of action and adopting soybeans engineered to tolerate 2,4-D, dicamba, and glufosinate, which increased the number of herbicides and total amounts applied. Our article on superweeds and the dicamba saga explains this cycle in detail.

Insecticide Seed Treatments

Much soybean pesticide use is invisible in traditional surveys because it comes coated on seeds. A 2015 study in Environmental Science & Technology by Margaret Douglas and John Tooker at Penn State found that neonicotinoid use increased rapidly between 2003 and 2011 as seed-applied products were introduced, marking an unprecedented shift toward preemptive insecticide use; by 2011, 34 to 44 percent of soybean hectares and 79 to 100 percent of corn hectares were treated. Seed treatments are often applied regardless of whether pests are present. A 2019 analysis in Scientific Reports by Spyridon Mourtzinis and colleagues pooled 194 randomized field studies in 14 states from 2006 to 2017 and found that neonicotinoid seed treatments provided negligible yield benefits for most soybean farmers, concluding that the practice appears to offer little benefit while adding cost and environmental exposure. Neonicotinoids are linked to harm to bees and aquatic insects, as described in our article on neonicotinoids and bees.

What Pesticide Residues Are in Soybeans?

Testing finds glyphosate residues in genetically modified soybeans but not in conventional or organic ones, while insecticide seed treatments add little, and residue levels are generally within legal limits. Because glyphosate is sprayed over glyphosate-tolerant soybeans during the growing season, residues can remain in the harvested beans. A 2014 study in Food Chemistry by Thomas Bøhn and colleagues in Norway analyzed 31 batches of soybeans from Iowa: genetically modified glyphosate-tolerant soybeans, conventional non-GM soybeans grown with chemical inputs, and organic soybeans. The GM soybeans contained glyphosate and its breakdown product AMPA at mean levels of 3.3 and 5.7 milligrams per kilogram, while conventional and organic batches contained none. The organic soybeans also differed in nutrient composition, with more protein and zinc and less saturated fat. The measured glyphosate levels were below the U.S. legal tolerance for soybeans, which is set by the EPA, but the study showed that residues in herbicide-tolerant soybeans can be substantial relative to other crops.

Where Residues End Up

Most U.S. soybeans are crushed into meal for animal feed and oil for food and industrial uses. Glyphosate is water-soluble, so it tends to concentrate in the meal fraction rather than in refined oil; soybean oil is highly refined, and residues in oil are generally very low. Soy protein ingredients, soy flour, and whole soybeans used in foods such as tofu, tempeh, edamame, and soy milk can contain residues depending on how the soybeans were grown. Food-grade soybeans for tofu and soy milk are often non-GM varieties, sometimes grown specifically for these markets, which may reduce glyphosate residues, though other herbicides can be used.

Is Soy Actually Healthy?

Soy is a nutritious, high-quality plant protein linked in research to heart benefits and is a staple in many diets; concerns about soy are mostly not supported by evidence for most people. Pesticide concerns are distinct from questions about soy as a food. Online claims that soy is toxic often focus on isoflavones, plant compounds that weakly interact with estrogen receptors. A 2016 review in Nutrients by Mark Messina evaluated clinical and epidemiological research and concluded that soy foods are sources of high-quality protein and healthful fat, with evidence suggesting they may reduce risk of coronary heart disease and breast and prostate cancer and alleviate menopausal hot flashes. Concerns about adverse effects are based primarily on animal studies, while human research supports the safety of soy foods. The review noted that the European Food Safety Authority concluded isoflavones do not adversely affect the breast, thyroid, or uterus of postmenopausal women. Traditional soy foods have been eaten for centuries in East Asia, where intake is far higher than in the United States.

Does Soy Affect Hormones or Testosterone?

A large meta-analysis of dozens of studies found that soy and its isoflavones do not lower testosterone or raise estrogen in men, so common fears about soy “feminizing” effects are not supported. Lists claiming that American soy is toxic circulate widely. Some concerns relate to farming practices, which are real; others relate to soy itself and are not supported by human research. A frequent claim is that soy feminizes men. A 2021 meta-analysis in Reproductive Toxicology by Katherine Reed, Mindy Kurzer, and colleagues pooled 41 clinical studies and found that neither soy nor isoflavone intake affected testosterone, free testosterone, estrogen, or sex hormone-binding globulin in men. Concerns about thyroid function apply mainly to people with untreated hypothyroidism or iodine deficiency, who should discuss soy intake and medication timing with a clinician. Soy contains phytates that reduce mineral absorption, as do other legumes and whole grains, which is generally not a problem in a varied diet. Soy-based infant formula is considered safe for infants who need it, though cow’s milk formula is usually preferred unless there is a reason to avoid it.

How to Reduce Pesticide Exposure From Soy

Soy product	Tips
Tofu, tempeh, soy milk, edamame	Choose USDA Organic; non-GMO labels avoid glyphosate-tolerant varieties but not all herbicides
Soy protein isolate and bars	Look for organic certification; protein powders vary widely in sourcing
Soybean oil	Highly refined; residues are generally very low
Processed foods with soy	Eating fewer ultra-processed foods reduces exposure from many ingredients
Animal products	Most soybean meal feeds livestock; organic meat, dairy, and eggs come from animals fed organic feed

Organic diets lower overall pesticide exposure quickly. A 2019 study in Environmental Research by Carly Hyland and colleagues found that urinary levels of several pesticides and their metabolites dropped substantially when four U.S. families switched to an all-organic diet for six days.

Fungicides: A Growing Trend

Beyond herbicides and insecticides, fungicide use on soybeans has grown in recent decades, partly in response to diseases such as frogeye leaf spot and white mold and partly from marketing claims of plant health benefits even without disease. Some studies have found that fungicide applications in the absence of significant disease provide little economic return. Resistance has also emerged; frogeye leaf spot populations resistant to strobilurin fungicides have been documented in several states. Extension specialists recommend scouting fields and applying fungicides based on disease risk rather than routinely.

What It Means for Farmers

For soybean farmers, rising pesticide costs squeeze profits, particularly when soybean prices are low. Herbicide programs using multiple products, seed treatments applied by default, and routine fungicides add up. Research suggesting that some of these inputs provide little benefit, such as neonicotinoid seed treatments in most fields, offers opportunities to cut costs. Diversified rotations, cover crops, narrow rows, and integrated pest management can reduce weed and pest pressure. Organic soybean production avoids synthetic pesticides and earns price premiums but requires intensive weed management and access to organic markets.

How Residue Limits Are Set

In the United States, the EPA sets legal limits, called tolerances, for pesticide residues on each crop, based on toxicity studies and estimated dietary exposure, with added safety factors for children. The FDA and USDA test foods for compliance. The current glyphosate tolerance for soybean seed is 20 parts per million, well above the levels measured in the Iowa study. Critics argue that tolerances are based largely on industry-submitted studies, may not fully account for combined exposures to multiple pesticides or effects of formulated products, and in some cases were raised to accommodate new uses. Regulators maintain that tolerances include wide safety margins. Either way, residues within legal limits are not the same as zero exposure.

Environmental Effects Beyond the Field

Pesticides applied to soybeans can move into streams, groundwater, and the air. Glyphosate and its breakdown product AMPA are frequently detected in U.S. streams in agricultural areas, usually at low concentrations. Neonicotinoids from seed treatments are highly water-soluble, and only a small fraction is taken up by the plant; much of the remainder can enter soil and water, where they may harm aquatic insects. Drift of herbicides like dicamba and 2,4-D can damage neighboring crops and wild plants that pollinators depend on. Reducing unnecessary applications, as suggested by the seed treatment research, benefits both farmers and the environment.

The Organic and Non-GMO Soy Market

Demand for organic and non-GMO soy has grown, driven by consumers of tofu, soy milk, and organic animal products. The United States imports substantial amounts of organic soybeans for feed because domestic organic production has not kept pace with demand. Non-GMO Project Verified soy avoids genetically engineered varieties, which reduces glyphosate residues, but non-GMO soybeans can still be grown with other synthetic herbicides. USDA Organic certification prohibits synthetic pesticides and is the stronger standard for reducing residues. Some food companies contract directly with farmers to grow food-grade organic or non-GMO soybeans with traceable supply chains. Where soybeans are grown matters too; our article on responsible soy and deforestation covers South American production.

Integrated Pest Management in Soybeans

Integrated pest management combines monitoring, thresholds, and multiple control tactics to minimize pesticide use. For soybeans, IPM practices include scouting fields regularly, treating insects such as soybean aphids only when populations exceed economic thresholds, rotating crops to break pest cycles, planting resistant varieties for diseases such as soybean cyst nematode, using cover crops and narrow rows to suppress weeds, and rotating herbicide modes of action. University extension programs provide region-specific IPM guidance. Studies show IPM can reduce pesticide use while maintaining yields and profits.

How Soybeans Became an American Staple

Soybeans, domesticated in East Asia thousands of years ago, became a major U.S. crop in the 20th century, valued for oil and high-protein meal for livestock. Today the United States is one of the world’s largest soybean producers and exporters, alongside Brazil. Most U.S. soybeans are grown in rotation with corn across the Midwest, and the large majority are genetically engineered for herbicide tolerance. The crop’s scale means that changes in farming practices, such as shifts in herbicide programs, have large effects on total pesticide use nationally.

The Shift to Multiple-Herbicide Soybeans

In the late 2010s and 2020s, soybeans tolerant to several herbicides became dominant. Varieties tolerant to 2,4-D, glyphosate, and glufosinate, and others tolerant to dicamba and glyphosate, allow farmers to combine herbicides over the growing crop. These systems help control resistant weeds but increase the number of active ingredients applied. The rapid rise of 2,4-D on soybeans, reflected in the 2023 survey data, illustrates how herbicide-tolerant traits shape chemical use. Dicamba’s regulatory history, including court vacaturs in 2020 and 2024 and a 2026 re-registration, has also influenced which systems farmers choose.

Indirect Exposure Through Animal Products

Most soybean meal is fed to poultry, pigs, cattle, and farmed fish. Pesticide residues in feed can transfer to animal products at low levels, though most residues are metabolized or excreted. Choosing organic meat, dairy, and eggs ensures animals were fed organic feed grown without synthetic pesticides. For most people, exposure through animal products is likely smaller than through plant foods directly treated with pesticides, but it contributes to overall dietary exposure.

Fermented Soy Foods

Traditional fermented soy foods such as tempeh, miso, natto, and soy sauce are made by fermenting soybeans with molds or bacteria. Fermentation can reduce compounds such as phytates, improve digestibility, and in the case of natto, produce vitamin K2. These foods have long histories in Asian diets. Choosing organic versions of these products reduces pesticide residues while retaining their nutritional benefits.

Looking Ahead

Soybean pest management will continue to evolve as weeds develop resistance to newer herbicides, regulators review dicamba and other products, and research clarifies which inputs provide real benefits. Precision spraying technologies that detect weeds and apply herbicide only where needed could reduce use significantly. Growing interest in regenerative and organic practices may also shift some production. For consumers, demand for organic and transparently sourced soy foods will help shape how soybeans are grown.

Soy Allergy

Soy is one of the major food allergens, more common in young children, many of whom outgrow it. U.S. food labeling law requires soy to be declared on packaged foods. Highly refined soybean oil is generally exempt from allergen labeling because refining removes most allergenic proteins, and many people with soy allergy tolerate it, though they should follow their allergist’s advice. Soy lecithin, a common emulsifier, contains small amounts of soy protein. People with soy allergy need to read labels carefully regardless of how the soybeans were grown.

Questions to Ask About Your Soy Foods

Is the product certified organic? If not, is it made from non-GMO soybeans, and does the company share how its soybeans are grown? Where are the soybeans sourced, domestically or imported? Is the product minimally processed, such as tofu, tempeh, or edamame, or highly processed with many additives? Asking these questions helps consumers choose soy foods that align with their health and environmental priorities.

A Balanced View

Pesticide use on U.S. soybeans has grown in complexity and cost, driven largely by glyphosate-resistant weeds and the widespread adoption of insecticide seed treatments. Herbicides are now applied to nearly all soybean acres, at an estimated cost of about $4 billion in 2023, and research suggests some inputs, like neonicotinoid seed treatments, provide little benefit for most farmers. Glyphosate residues are found in glyphosate-tolerant soybeans, though typically below legal limits. Soy foods themselves are healthy, and human studies do not support claims that soy is toxic. Consumers who want to reduce pesticide exposure can choose organic soy foods, while farmers can lower costs and environmental impacts through integrated pest management.

Practical Takeaways

Enjoy soy foods as part of a healthy diet; human research supports their safety. Choose USDA Organic tofu, tempeh, soy milk, and edamame to reduce herbicide residues. Remember that non-GMO labels avoid glyphosate-tolerant varieties but not all pesticides. Eat fewer ultra-processed foods with soy ingredients. Support farmers who use integrated pest management and diversified rotations.

Common Myths

“Soy is toxic.” Human studies support the safety of soy foods, which provide high-quality protein and may reduce heart disease risk.

“Soy lowers testosterone in men.” A meta-analysis of 41 clinical studies found no effect on male reproductive hormones.

“Non-GMO soy is pesticide-free.” Non-GMO soybeans avoid glyphosate-tolerant traits but can be grown with other synthetic pesticides.

“Herbicide-tolerant crops reduced herbicide use.” Initial simplification gave way to rising use as resistant weeds spread.

“Seed treatments always boost yields.” Nearly 200 field trials found negligible benefits for most soybean farmers.

Key Terms

Herbicide-tolerant soybeans: Varieties engineered to survive specific herbicides sprayed over the crop.

AMPA: Aminomethylphosphonic acid, the main breakdown product of glyphosate.

Seed treatment: Pesticides coated onto seeds before planting.

Tolerance: The legal maximum pesticide residue allowed on a food.

Isoflavones: Plant compounds in soy that weakly interact with estrogen receptors.

The Bottom Line

American soybean farmers do spend far more on pesticides than they once did. In 2023, herbicides were applied to 96 percent of U.S. soybean acres, with an estimated 89 million kilograms used at a cost of about $4.1 billion, driven largely by glyphosate-resistant weeds that pushed farmers toward 2,4-D, glufosinate, and other products. Neonicotinoid seed treatments became routine despite negligible yield benefits for most farmers. Glyphosate residues are found in glyphosate-tolerant soybeans, though typically within legal limits. Soy itself is a healthy food, and claims that it is toxic are not supported by human research. Choosing organic soy foods is the most effective way for consumers to reduce herbicide exposure from soy.

Frequently Asked Questions

How much pesticide is used on soybeans?

U.S. soybean production uses large amounts of herbicide, chiefly glyphosate, because most soybeans are genetically engineered to tolerate it. Government data for 2023 show growers applied roughly 89 million kilograms of herbicides to soybeans, worth several billion dollars. Insecticides and fungicides are used in far smaller quantities. This heavy herbicide use is a defining feature of conventional, GM soybean farming.

Are there pesticide residues in soy products?

Testing finds glyphosate residues in genetically modified soybeans but generally not in conventional non-GM or organic soybeans. Residue levels in GM soy are typically within legal limits. Processing can reduce residues in some soy products. People who want to minimize glyphosate exposure from soy can choose organic soy products, which are grown without synthetic herbicides like glyphosate.

Is soy healthy or bad for you?

Soy is a nutritious, high-quality plant protein that also provides fiber, vitamins, and minerals, and research links soy foods to heart benefits and other positive effects. For most people, soy is a healthy part of the diet. Many fears about soy, including claims that it harms hormones or causes cancer, are not supported by the weight of scientific evidence.

Does soy lower testosterone or raise estrogen in men?

No. A large meta-analysis combining many studies found that neither soy foods nor soy isoflavones lower testosterone or raise estrogen levels in men. The plant compounds in soy, called isoflavones, are not the same as human estrogen and do not have feminizing effects at normal dietary intakes. Common fears about soy and male hormones are not backed by the research.

Should I choose organic soy to avoid glyphosate?

If reducing glyphosate exposure is a priority for you, choosing organic soy products is effective, since organic farming prohibits synthetic herbicides like glyphosate, and organic soybeans test free of its residues. For most people, residues in conventional soy are within safety limits, so this is a personal choice. Either way, soy remains a nutritious protein, and the decision is about minimizing residues, not avoiding an unhealthy food.

References

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Last updated: October 6, 2026