Glyphosate: New study reinforces cancer link, raising urgent concerns for global health and farming practices
GM Watch, an organization and website dedicated to providing information on the risks of GM crops and hazardous agro-chemicals, released an article on June 10, 2025. This article, based on a significant study involving scientists from Europe and the US, concerns glyphosate, the world's most widely used herbicide. It is being closely read by those interested in food safety and rural health.
Kapil Shah, an activist from Jatan Organic Farming organization in India, commented on the study, stating that without remedial steps, India, particularly rural India, will be severely affected by cancer within a decade or two due to the widespread use of weedicides and pesticides. The study, on which the GM Watch article is based, indicates that even low doses of the controversial weed-killer caused multiple types of cancer in rats.
In this long-term study, published on June 10, glyphosate alone and two commercial glyphosate-based formulations—Roundup BioFlow (MON 52276) used in the EU, and Ranger Pro (EPA 524-517) used in the US—were administered to rats via drinking water starting in prenatal life. The doses used are currently considered safe by regulatory agencies and correspond to the EU Acceptable Daily Intake (ADI) and the EU’s No Observed Adverse Effect Level (NOAEL) for glyphosate. Glyphosate is used on over 80% of GM crops.
Across all three treatment groups in the study, increased incidences of benign and malignant tumors were observed at multiple anatomical sites compared to control groups. These tumors appeared in haemolymphoreticular tissues (leukemia), skin, liver, thyroid, nervous system, ovary, mammary gland, adrenal glands, kidney, urinary bladder, bone, endocrine pancreas, uterus, and spleen (hemangiosarcoma). Increased early deaths were also noted due to other solid tumors.
The findings regarding leukemia are particularly strong and could offer crucial support for plaintiffs in court cases who allege that exposure to Roundup caused their Non-Hodgkin lymphoma, another type of blood cancer, as stated in the article.
“We observed early onset and early mortality for a number of rare malignant cancers, including leukemia, liver, ovary, and nervous system tumors. Notably, approximately half of the deaths from leukemia seen in the glyphosate and GBHs [glyphosate-based herbicide] treatment groups occurred at less than one year of age, comparable to less than 35-40 years of age in humans. By contrast, no case of leukemia was observed in the first year of age in more than 1600 Sprague-Dawley historical controls in carcinogenicity studies conducted by the Ramazzini Institute and the National Toxicology Program (NTP),” stated Dr. Daniele Mandrioli, Director of the Cesare Maltoni Cancer Research Center of the Ramazzini Institute and Principal Investigator of the study.
The multi-institutional Global Glyphosate Study (GGS) is being led by the Cesare Maltoni Cancer Research Center of the Ramazzini Institute in Italy.
“Our findings reinforce IARC’s (International Agency for Research on Cancer’s) classification of glyphosate as a probable human carcinogen and are consistent with experimental animal studies as well as human correlational and weight-of-evidence evaluations that have reported associations between glyphosate exposure and certain cancers, particularly hematological malignancies,” said Dr. Melissa Perry, study co-author and Environmental Epidemiologist at George Mason University College of Public Health.
The Global Glyphosate Study is described in the GM Watch article as the most comprehensive toxicological study ever conducted on glyphosate and glyphosate-based herbicides. It aims to provide vital data for government regulators, policymakers, and the general public.
"This robust study, based on a protocol encompassing pre- and post-natal development, fulfills the need for sound scientific evidence on the toxicology of glyphosate. The results highlight the tumorigenic potential of glyphosate and glyphosate-based products at dose levels considered as 'safe'. This new evidence has to be carefully considered by the regulatory authorities globally," added Dr. Alberto Mantovani, study co-author and member of the Italian National Food Safety Committee (CNSA).
The GGS’s findings on glyphosate’s toxicity to the microbiome, which were peer-reviewed and published in late 2022 and presented at the EU Parliament in 2023, also showed adverse effects at doses currently considered safe in the EU (0.5 mg/kg bw/day, equivalent to the EU Acceptable Daily Intake), the article notes.
Furthermore, the article adds that the GGS previously published a pilot study demonstrating endocrine and reproductive toxicity in rats at glyphosate doses currently considered safe by US regulatory agencies. These findings were later confirmed in a human population of mothers and newborns exposed to glyphosate during pregnancy.
“The findings from this carefully conducted study, and especially the observation that prenatal exposures of infant rats to glyphosate during pregnancy increase incidence and mortality from early-life leukemia, 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," concluded Dr. Philip Landrigan, study co-author and Director of the Program for Global Public Health and the Common Good at Boston College.
The reference for this study is: Panzacchi S et al (2025). Carcinogenic effects of long-term exposure from prenatal life to glyphosate and glyphosate-based herbicides in Sprague–Dawley rats. Environmental Health volume 24, Article number: 36 (2025). The title of the article released by GM Watch is—International study reveals glyphosate weed-killers cause multiple types of cancer.
This study must be viewed in the broader context where powerful multinational companies are introducing several products highly hazardous to people, exposing them to serious ailments and diseases, including cancer. As the incidence of various serious afflictions and diseases, including several types of cancer, has rapidly increased in many countries, various public interest groups have sought scientific assistance to determine if highly hazardous products are responsible. With a significant amount of scientific evidence now available regarding such products, cases seeking billions of dollars in damages have been decided in favor of individuals whose health was harmed, and many more cases are pending. Simultaneously, powerful corporations have employed various tactics to evade responsibility, even resorting to merging with other companies. While this is the situation in some of the richest countries, the situation in several parts of the Global South is even worse, as some highly hazardous products banned or heavily regulated in richer countries are exported there and used much more indiscriminately. In the context of hazardous agro-chemicals and weed-killers or their ingredients, much controversy has centered around cancer-linked glyphosate and Roundup.
A disclosure by the leading environmental organization Friends of the Earth last year (2024) revealed that Residential Roundup products are more toxic to consumers and the environment than ever before. “Not only has manufacturer Bayer [OTCMKTS: BAYRY] failed to remove glyphosate from all Roundup products, as promised, but new formulations of Roundup are 45 times more toxic to human health, on average, following long-term, chronic exposure,” Friends of the Earth stated in a press release dated October 22, 2024. They also pose greater risks to the environment.
This press release by Friends of the Earth (FoE) states, “Bayer announced it would remove glyphosate from consumer products starting in 2023 in response to tens of thousands of lawsuits linking the weed-killer to non-Hodgkin’s lymphoma. Friends of the Earth reviewed Roundup weed-killers for sale at the two largest U.S. home and garden retailers – Home Depot [NYSE: HD] and Lowe’s [NYSE: LOW] – to determine whether the company followed through as of October, 2024.”
FoE adds, “Not only do several Roundup products still contain glyphosate, but eight new Roundup products contain chemicals of dramatically greater concern. With no requirement from the Environmental Protection Agency (EPA) to warn consumers of the new dangers, people are unknowingly being exposed to higher risks.”
According to the FoE statement, “Roundup products sold to consumers now contain combinations of four new active ingredients as replacements for glyphosate: diquat dibromide, fluazifop-P-butyl, triclopyr, and imazapic. All four chemicals pose a greater risk of long-term and/or reproductive health problems than glyphosate, based on the EPA’s evaluation of safety studies. They have been linked to a variety of harms to human health, including birth and developmental abnormalities; reproductive dysfunction; kidney or liver damage; and irritation, inflammation, or allergic reactions affecting the skin, eyes, and respiratory system. The worst offender is diquat dibromide, found in all of the new Roundup formulations. It is 200 times more chronically toxic than glyphosate, is classified as a highly hazardous pesticide, and is banned in the European Union.”
Further, this statement says, “In addition to the threat to human health, the new Roundup weed-killers also endanger animals and the environment. On average, they are more toxic to bees, birds, fish, aquatic organisms, and earthworms. They are also more persistent in the environment and more likely to leach into groundwater, increasing the risk of contaminating waterways and drinking water.”
“The human toll of Roundup is enormous – tens of thousands of people have lost their lives and their health because of this toxic weed-killer. With the new formulations of Roundup, Bayer had the opportunity to make us safer, but it did the opposite,” said Kendra Klein, deputy director of science for Friends of the Earth.
This statement adds, “Internal corporate documents unearthed during the Roundup litigation show the profound extent of deceit and disinformation that Monsanto deployed to cover up the dangers of Roundup. Our analysis reveals that Bayer continues to mislead consumers, exposing them to far greater risks with no warning. While the new active ingredients are listed on Roundup product labels, as required by law, there is no language alerting consumers to the higher risks they pose. The average consumer – even if they notice the new ingredients – knows little about the toxicology of glyphosate compared to the new ingredients that are taking its place.”
The FoE statement also informed that over 120 organizations had called on Home Depot and Lowe’s to take action to #RejectRoundup and make their garden product shelves safer overall.
At the same time, concerns are also increasing in many countries regarding the agricultural use of chemical weed-killers, as very serious health hazards could be observed in remote villages where monitoring is difficult, and the linkages between highly hazardous products and serious diseases may be harder to establish, even though such diseases are certainly increasing with the wider spread of these products. Highly hazardous herbicides are being promoted as a package along with certain seed varieties and are an integral part of the spread of several GM crops, which themselves are health hazards and ecologically disruptive, as pointed out by several senior scientists. Thus, the real task and challenge before us is to work for the spread of natural farming and ecologically protective farming so that health and sustainable livelihoods can be protected, and at the same time, biodiversity and the environment can also be preserved.
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The writer is Honorary Convener, Campaign to Save Earth Now. His recent books include When the Two Streams Met (Freedom Movement of India), Man over Machine (Mahatma Gandhi’s ideas for present times), and India’s Quest for Sustainable Farming and Healthy Food
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