What is glyphosate?

Henri Martin, a Swiss chemist, was the first to synthesise glyphosate while trying to develop new pharmaceuticals in 1950.

Glyphosate is a chemical compound that works as an effective herbicide, or weed killer. It’s the most commonly used herbicide chemical across the world. Glyphosate may be sprayed anywhere there are unwanted plants — from commercial farms to private backyards.

Henri Martin, a Swiss chemist, was the first to synthesise glyphosate while trying to develop new pharmaceuticals in 1950. But the chemical didn’t have much use in the pharmaceutical world.

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Twenty years later, John E Franz, a chemist at the agrochemical company Monsanto, independently synthesised glyphosate. Franz found that glyphosate was a highly efficient plant-killer. Monsanto promptly patented the chemical and began selling its glyphosate herbicide under the trade name Roundup in 1974. Between 1995 and 2014, global glyphosate use grew 12-fold.

Glyphosate has been used more than any other agriculture chemical, with an estimated 8.6 billion kg of it sprayed since 1974 to help grow everything from peppers to oranges.
When the chemical is sprayed onto a plant, it usually seeps into the plant via the leaves.

From there, glyphosate can travel from cell to cell and spread to the stem and the roots, infecting the entire plant. Glyphosate is derived from an amino acid called glycine and plant cells treat glyphosate as though it were amino acid.

Plants use amino acids to build things like enzymes and proteins that it needs in order to grow, through a process called amino acid synthesis. But once glyphosate ends up in the plant’s amino acid synthesis cycle, it kills everything.

Although glyphosate has cut farmers’ costs and helped remove invasive plants, people have grown increasingly skeptical about whether the benefits outweigh the risks to human and environmental health. Recent research has shown that the chemical may be harming the wrong plants, in addition to wildlife and people.

Even if glyphosate is targeted at a specific plant, it can end up in unexpected places. That means that it can hurt any plant it reaches. And no matter how carefully someone sprays it, a large portion of the liquid solution will wind up in the soil below or in the form of droplets, which can travel in air. Glyphosate has also made headlines for its suspected link to a class of cancers called non-Hodgkin lymphoma (NHL).