How does glyphosate control weeds?

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weeding — weed Weeds being removed by hand from a parsley patch.

Glyphosate controls weeds by acting as a nonselective herbicide that inhibits the enzyme EPSP synthase.1

This enzyme is essential for the shikimic acid pathway, which regulates the synthesis of aromatic amino acids—specifically phenylalanine, tryptophan, and tyrosine. These amino acids are critical building blocks for the proteins required for plant growth. By inhibiting EPSP synthase, glyphosate prevents the plant from producing these necessary components and causes a toxic accumulation of shikimate.1

Because these biological processes are fundamental to most plant life, glyphosate is toxic to the majority of plants upon contact with their foliage. While some species possess natural tolerance or have developed resistance through genetic mutations, the herbicide remains a primary tool for managing invasive and unwanted vegetation in agricultural and environmental settings.1