Glufosinate-ammonium is a non-selective contact herbicide used in consumer garden weedkiller products — positioned as a "glyphosate alternative" following consumer and retail pressure to reduce glyphosate use. It kills weeds by inhibiting glutamine synthetase, the enzyme that converts toxic ammonium to the amino acid glutamine in plants, causing ammonium accumulation and plant death. Glufosinate is sold in products including Bayer's Finale and own-brand garden centre products. While marketed as an alternative to the more controversial glyphosate, glufosinate has its own significant health concerns: it is classified as a reproductive toxicant category 1B (may damage fertility or the unborn child) under EU/UK CLP regulation, and its neurotoxicity — caused by its structural similarity to the amino acid GABA — is more firmly established than that of glyphosate. Glufosinate was expected to be banned in the EU from 2022 but received a short extension; its future approval status is uncertain.
Where it's found
Consumer garden weedkiller products — Finale, various "path and patio" weedkillers, and some "glyphosate-free" alternative weedkillers sold in garden centres and hardware stores. Agricultural use in genetically modified herbicide-tolerant crops (glufosinate-tolerant GM crops in North and South America). Some garden multi-purpose spray products for total weed clearance. Products may not prominently display glufosinate as the active ingredient — checking the active ingredient on the back of any weedkiller product is recommended.
Routes of exposure
Dermal contact during application without gloves — glufosinate is absorbed through human skin. Inhalation of spray mist during application. Children playing on recently treated surfaces who have hand-to-mouth contact with residues. Dietary exposure from food imports (particularly from GM-crop-using countries where glufosinate is more extensively applied) — glufosinate residues are permitted in some food products under UK/EU MRLs. Oral ingestion via contaminated surfaces — glufosinate degrades more rapidly in soil than some persistent herbicides but can persist for several weeks in moist conditions.
Health concerns
Glufosinate is a structural analogue of GABA (gamma-aminobutyric acid) — the brain's primary inhibitory neurotransmitter — and at sufficient doses causes CNS hyperexcitability, tremor, seizures, and respiratory failure by competitively inhibiting GABA receptors. Intentional ingestion cases document severe neurological toxicity. At consumer exposure levels, acute neurological toxicity is unlikely but not impossible in children. The reproductive toxicity classification (Cat 1B) is based on animal studies showing teratogenicity at doses causing maternal toxicity — glufosinate causes neural tube defects and foetal death in animal studies and its glutamine synthetase inhibition is relevant to embryonic development, where glutamine is a critical metabolite.
Evidence
Glufosinate GABA receptor antagonism and resulting CNS toxicity is mechanistically and clinically established. Reproductive and developmental toxicity in animals is established, forming the basis for Cat 1B CLP classification. This classification is more severe than glyphosate's disputed classification, yet glufosinate has received far less public attention. EU EFSA's review concluded that glufosinate could not be renewed under current criteria primarily due to reproductive toxicity. UK HSE retained approval while undertaking independent review. Dietary residue exposure via food imports is real but below established TDI levels for most consumers.
Who's most at risk
Pregnant women — glufosinate's reproductive toxicity classification specifically covers the unborn child; the EU Cat 1B classification means it "may damage the unborn child." Women of childbearing age who may not yet know they are pregnant. Children who play on recently treated surfaces. Garden centre workers and landscapers with repeated professional exposure.
Regulatory status
RegulationGlufosinate-ammonium's EU authorisation lapsed in 2022 and it has not been renewed — it is no longer authorised in the EU. UK (post-Brexit) retained a time-limited approval that is under active HSE review. Products still authorised in the UK during the review period may legally be sold. Consumers should check current authorisation status on the HSE pesticide database before purchase. The Cat 1B reproductive toxicant classification means products carry mandatory hazard labelling.
How to reduce your exposure
Do not use glufosinate products if pregnant or planning to become pregnant — the Cat 1B reproductive toxicity classification is a serious regulatory signal. Check current UK HSE authorisation status before purchasing weedkillers labelled as "glyphosate alternatives" — glufosinate products may no longer be authorised for sale. Physical weed control methods (flame weeding, boiling water, hoeing) are fully effective for most garden situations and carry no reproductive risk. For selective weed control on paths and patios, read all product labels carefully and verify the active ingredient on the Health and Safety Executive's UK pesticide database at www.pesticides.gov.uk.
The nutrition connection
Glufosinate inhibits glutamine synthetase — an enzyme that requires manganese as a cofactor. Adequate dietary manganese (from wholegrains, nuts, leafy vegetables, and tea) supports this enzyme's function. Glufosinate's GABAergic mechanism makes GABA nutrition relevant: adequate B6 (required for GABA synthesis from glutamate via glutamate decarboxylase), magnesium (a GABA receptor co-modulator), and taurine (which has GABAergic activity) all support inhibitory neurotransmitter tone. Folate is directly relevant to the reproductive toxicity concern — adequate folate from leafy greens and legumes supports neural tube development and DNA methylation throughout early pregnancy.