Glyphosate is the most common active ingredient in herbicide products globally. This synthetic chemical is a non-selective, broad-spectrum weed killer that has been used in agriculture and residential gardening since the 1970s. Its high efficacy in controlling a vast range of unwanted vegetation has made it a foundational tool for weed management. Hundreds of commercial products containing glyphosate are available to both professional farmers and home users, with concentrations and formulations varying significantly.
Defining Glyphosate and Its Mechanism
Glyphosate, chemically known as N-(phosphonomethyl) glycine, functions as a systemic herbicide, meaning it is absorbed through the foliage of a plant and then translocated throughout its tissues, including the roots. It is classified as an amino acid synthesis inhibitor that targets a specific biochemical process within the plant. The chemical works by inhibiting the enzyme 5-enolpyruvylshikimate-3-phosphate synthase, often referred to as EPSP synthase.
This enzyme is part of the shikimic acid pathway, which is responsible for the plant’s production of essential aromatic amino acids. Blocking this pathway starves the plant of the proteins necessary for growth and survival, leading to a slow, irreversible decline. Since the shikimic acid pathway is present in plants but absent in animals and humans, glyphosate exhibits a selective toxicity that targets plants without affecting mammalian biology through the same mechanism.
Identifying Commercial Products Containing Glyphosate
The most recognizable product containing this active ingredient is Roundup, which was the original commercial formulation developed by Monsanto. Due to the expiration of the original patent, hundreds of generic and branded glyphosate-based herbicides are now sold under various names by many different manufacturers. These products can be broadly categorized into consumer-grade formulations and professional-grade agricultural concentrates.
Residential products typically feature lower concentrations, often ranging from 1% to 18% glyphosate, and are sold as ready-to-use sprays or small concentrated bottles. Professional and agricultural formulas, such as generic 41% or 50% solutions, are far more concentrated and intended for dilution before large-scale application. The total formulation includes the active glyphosate salt and various inert ingredients, such as surfactants, which enhance the chemical’s ability to penetrate the leaf surface and improve effectiveness.
Application Contexts and Target Weeds
Glyphosate-based herbicides are used in a wide variety of settings due to their non-selective nature. In non-agricultural settings, they are commonly applied for total vegetation control along fence lines, driveways, sidewalks, and railway beds. Municipal and industrial users rely on these products for clearing areas before construction or managing vegetation in utility rights-of-way.
The largest volume of use is in agriculture, particularly with genetically modified “Roundup Ready” varieties, such as corn, soy, and cotton. These crops are engineered to resist the herbicide, allowing farmers to spray directly over the growing crops to eliminate weeds without harm. Glyphosate is a post-emergent herbicide effective against both annual and perennial grasses and broadleaf weeds. Its systemic action kills the entire plant, including underground roots and rhizomes, preventing rapid regrowth.
Regulatory Status and Labeling Requirements
In the United States, the U.S. Environmental Protection Agency (EPA) is the governing body responsible for regulating glyphosate-based products under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA). The EPA conducts a registration review of the chemical approximately every 15 years to ensure that it continues to meet safety standards. The agency has consistently concluded that glyphosate is not likely to be carcinogenic to humans when used according to the current label instructions.
All commercial labels must adhere to strict requirements, including specific instructions for application rates and mandated safety warnings. These warnings often include requirements for the use of Personal Protective Equipment (PPE) to minimize applicator exposure. Labels also contain detailed instructions for managing spray drift to protect non-target plants and address potential ecological risks. While the International Agency for Research in Cancer (IARC) classified glyphosate as “probably carcinogenic to humans,” the EPA and other international regulatory bodies, such as the European Food Safety Authority (EFSA), maintain a different regulatory stance based on their comprehensive data reviews.