Glyphosate

Ball-and-stick Stick Space-filling

Drag to rotate; pinch or Ctrl + scroll to zoom. Arrow keys rotate, + − zoom, R resets.

18 atoms, 17 bonds.

IUPAC name: 2-(phosphonomethylamino)acetic acid
Molar mass: 169.073(15) g/mol
Atoms: 18
SMILES: C(C(=O)O)NCP(=O)(O)O
InChIKey: XDDAORKBJWWYJS-UHFFFAOYSA-N
PubChem CID: 3496

Made of

Structural formula of glyphosate. Each unlabelled corner is a carbon atom, and the four hydrogens on carbon are not drawn. It shows which atoms are joined to which, not the shape. The model above shows the shape.

Weed killers such as Roundup carry glyphosate as their active ingredient, and the US National Toxicology Program (NTP) calls it the most widely used herbicide worldwide. Its backbone is the amino acid glycine: HSDB, the Hazardous Substances Data Bank, names it N-phosphonomethyl glycine. The added piece hangs from glycine’s nitrogen, a CH₂ group carrying a phosphonic acid, one phosphorus atom bonded to three oxygens. In IUPAC naming it is 2-(phosphonomethylamino)acetic acid, with a molar mass of 169.07 g/mol.

Its white, odourless crystals decompose at 230 °C, HSDB records, and the acid and all its salts are non-volatile and stable in air. It is made from phosphorous acid, glycine and formaldehyde. Glyphosate was first registered in the United States in 1974, according to the US Environmental Protection Agency (EPA).

Structure and bonding

Glyphosate is one chain with no ring, built from 18 atoms: three carbon, eight hydrogen, one nitrogen, five oxygen and one phosphorus. A carboxyl group closes one end: a carbon with one double-bonded oxygen and one O–H. Inward come a CH₂, the nitrogen with its single hydrogen, and another CH₂ bonded to the phosphorus. That atom carries one double-bonded oxygen and two O–H groups.

In the Ball-and-stick view each double bond appears as a pair of sticks. In the model’s computed coordinates, P=O measures 1.50 Å and each P–OH 1.62 Å, the same pattern as C=O at 1.22 Å beside C–OH at 1.35 Å. In the Space-filling view the phosphorus and its three oxygens make the larger end.

The drawing is a neutral molecule with its three acidic hydrogens on oxygen and no formal charges. HSDB records the pure solid as a zwitterion instead, the double-ion form explained for glycine. ChEBI, a database of biological chemicals, lists glyphosate as the conjugate acid of the anions glyphosate(1−) and glyphosate(2−), formed as it gives up protons. Weed-killer products use its isopropylamine and sodium salts.

Where it turns up

Agriculture is its main use, according to the US Food and Drug Administration (FDA), with forestry and lawn and garden care besides. Its largest use sites in the United States include hay and pasture, soybeans and field corn, HSDB reports. The EPA lists cotton, canola, alfalfa and sugar beet among its other crops. Off the farm it keeps rights of way clear, clears weeds from pine, poplar and Christmas-tree plantings, and removes invasive weeds where habitats are being restored.

Trace residues may be left on some fruits, vegetables and cereals, the EPA says. FDA testing of corn, soybeans, milk and eggs found none in any milk or egg sample. In soil glyphosate binds tightly yet bacteria break it down quickly, ATSDR (the Agency for Toxic Substances and Disease Registry) reports. Nor does it accumulate along the food chain. The NTP names the microbial product as (aminomethyl)phosphonic acid, AMPA.

Why it matters

Glyphosate blocks an enzyme plants need for growth, EPSPS, short for 5-enolpyruvyl-3-shikimate phosphate synthase. Taken up through the leaves, it is non-selective, registered even for ground where all vegetation is to go. Mixed with other substances it is absorbed more readily and works better, the NTP notes.

Many crops have been genetically engineered to resist it, which the NTP gives as the main reason for its broad use. Spraying removes the weeds and spares a resistant crop such as Roundup Ready soybeans. Because it controls so many kinds of weed, it also lets growers turn the soil less or not at all, in reduced-tillage and no-till farming, the EPA says.

The EPA’s 2017 assessment judged glyphosate not likely to cause cancer in humans, consistent with regulators’ conclusions in Canada and the European Union. In 2015 IARC, the International Agency for Research on Cancer, placed it in Group 2A, probably carcinogenic to humans in the EPA’s wording. The EPA expects to finish an updated human health risk assessment in late 2026.

Properties

Properties of glyphosate Molar mass summed from IUPAC/CIAAW 2024 standard atomic weights; formula, atom and bond counts and PubChem's molecular weight from PubChem CID 3496.
Property	Value	Unit	Source
Molecular formula (Hill order)	C₃H₈NO₅P
Molar mass	169.073(15) g/mol	g/mol	IUPAC/CIAAW 2024
Carbon atoms	3
Hydrogen atoms	8
Nitrogen atoms	1
Oxygen atoms	5
Phosphorus atoms	1
Bonds	17
Single bonds	15
Double bonds	2
PubChem molecular weight	169.07 g/mol	g/mol	PubChem

Safety

Glyphosate can seriously damage the eyes: the EU classification gives it the signal word Danger and also classes it as toxic to aquatic life over the long term. Japan’s classification adds that it is suspected of causing cancer and of damaging fertility or the unborn child. ATSDR has linked glyphosate products to nose irritation and asthma in the people who use them. The PubChem Laboratory Chemical Safety Summary and ATSDR’s ToxFAQs on glyphosate are the reference sheets.

Questions

What groups make up a glyphosate molecule?

It is a short chain of 18 atoms with no ring: a carboxyl group, COOH, at one end, an N–H between two CH₂ groups in the middle, and a phosphonic acid group, PO(OH)₂, at the other. ChEBI, a database of biological chemicals, describes it as formally made by joining the methyl carbon of methylphosphonic acid to the amino group of glycine. CAMEO Chemicals, a hazard database, files it under carboxylic acids, amines and organic phosphonates at once.

Why do the EPA and IARC classify glyphosate differently?

Glyphosate's two classifications answer different questions, on the EPA's account. IARC, the International Agency for Research on Cancer, judges whether a chemical can cause cancer under any conditions, while the EPA weighs the risk at the exposures people meet in practice. IARC put glyphosate in Group 2A, probably carcinogenic to humans, in 2015, while the EPA's 2017 assessment rated it not likely to cause cancer in people.

Does glyphosate damage DNA?

Neither glyphosate nor AMPA, its microbial breakdown product, caused permanent changes to DNA in tests by the US National Toxicology Program (NTP). Glyphosate alone caused no DNA damage, so the NTP judged that the damage seen with the formulations likely came from their other ingredients. The NTP's findings do not exclude glyphosate causing cancer by other mechanisms. IARC, the International Agency for Research on Cancer, found strong evidence of DNA damage from glyphosate and its formulations, the NTP reports.

What happens to glyphosate inside the body?

In mammals, birds and fish, HSDB (the Hazardous Substances Data Bank) records rapid elimination, no chemical change and little held in the tissues, and glyphosate does not accumulate in edible tissue. Some published studies suggest that human gut bacteria convert it to AMPA, (aminomethyl)phosphonic acid, the NTP notes. The EPA found no indication in the available data of any interaction with oestrogen, androgen or thyroid pathways.

Made of the same elements

C₁₀H₁₆N₅O₁₃P₃ Adenosine triphosphate 47 atoms, 49 bonds.