In a long-term study published in Environmental Health, researchers found that early-life exposure to glyphosate-based herbicides increased cancer risk in rats, even at exposure levels considered “safe” under EU regulations.
In short:
- Exposure to glyphosate herbicides caused multiple benign and malignant tumors in rats, including leukemia and cancers of the skin, liver, thyroid, nervous system, ovary, uterus, and kidneys, among others.
- Many of these tumors are typically extremely rare in rats, and the increased risk was seen in both males and females.
- Multiple tumors occurred early in life and increased the risk of early death.
- In some cases, the consumer weed killer formulations (Roundup Bioflow and RangerPro) were more toxic than the glyphosate active ingredient alone.
Key quote:
“The findings from this carefully conducted study… [are] a powerful reminder of human infants’ great vulnerability to toxic chemicals and strong reason to eliminate glyphosate from the production of foods consumed by pregnant women and their children.”
- Study author Phil Landrigan, via a statement published by the Global Glyphosate Study
Why this matters:
In 2015, glyphosate was formally classified as “probably carcinogenic to humans” by the International Agency for Research on Cancer, an agency of the World Health Organization (WHO). Despite this, glyphosate-based herbicides are the most commonly used weed killers worldwide, and are readily found in food, water, and dust, indicating widespread exposure. The exposure levels associated with cancer in this study fall within the EU’s acceptable daily intake limits, leading to calls for updated restrictions on glyphosate’s use to better protect human health.
Related EHN coverage:
- Glyphosate, explained
- Op-ed: If Bayer really wanted to stand with farmers, it would stop selling them toxics
More resources:
- EHN and palabra: Adrift: Communities on the front lines of pesticide exposure fight for change, a special 3-part series with infographics, available in English and Spanish.
- The New Lede: New study adds to evidence that glyphosate weed killer can cause cancer, Bayer settles Missouri Roundup case mid-trial; looks to US Supreme Court, and Seeking answers to a cancer crisis in Iowa, researchers question if agriculture is to blame
Panzacchi, Simona et al. for Environmental Health vol. 24. June 10, 2025
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