No, glyphosate does not cause cancer. But don’t just take my word for it. Please also consider statements from multiple authorities who reviewed both robust glyphosate data sets and peer-reviewed literature, quoted below. Over the last 25 years or more, these expert reviewers have not wavered from the science-based conclusion that glyphosate does not cause cancer. What I find quite compelling is that over the years, the volume of toxicology studies on glyphosate has grown considerably and has increased confidence in the repeated scientific conclusions on this topic. Between 1981 and 2009, glyphosate was tested in at least thirteen long-term/carcinogenicity studies, eight in rats and five in mice, all of which were evaluated by independent experts, who all concluded that glyphosate does not cause cancer.
World Health Organization/Food and Agriculture Organization Joint Meeting on Pesticide Residues (WHO/FAO JMPR, 1987):
“The chronic toxicity of glyphosate is low; the only significant toxicity seen in a number of animal bioassays was mild hepatotoxicity at high doses in mice. There is no evidence of carcinogenicity.”
Canadian Pest Management Regulatory Agency (1991):
“Health and Welfare Canada has reviewed the glyphosate toxicology database, which is considered to be complete. The acute toxicity of glyphosate is very low. The submitted studies contain no evidence that glyphosate causes mutations, birth defects or cancer.”
US Environmental Protection Agency, Registration Eligibility Document (US EPA, 1993):
“Based on the results of its reregistration review, EPA has concluded that all registered uses of glyphosate are eligible for reregistration. The Agency has classified glyphosate as a Group E carcinogen (signifies evidence of noncarcinogenicity in humans).”
World Health Organization International Programme on Chemical Safety, Environmental Health Criteria 159 (WHO IPCS, 1994):
“Animal studies show that glyphosate is not carcinogenic, mutagenic or teratogenic.”
World Health Organization/Food and Agriculture Organization Joint Meeting on Pesticide Residues (WHO/FAO JMPR, 2004)
“In view of the absence of a carcinogenic potential in animals and the lack of genotoxicity in standard tests, the Meeting concluded that glyphosate is unlikely to pose a carcinogenic risk to humans.”
Australian Pesticides and Veterinary Medicines Authority (APVMA, 2013) review of the Earth Open Source report “Roundup and Birth Defects: Is the Public Being Kept in the Dark?”
“The APVMA currently has no data before it suggesting that glyphosate products registered in Australia and used according to label instructions present any unacceptable risks to human health, the environment and trade …”
“The weight and strength of evidence shows that glyphosate is not genotoxic, carcinogenic or neurotoxic. “
Glyphosate Reevaluation Assessment Report, Germany Rapporteur Member State for the European Annex I Renewal of Glyphosate (2014)
“…glyphosate was considered unlikely to pose a carcinogenic risk in humans …”
“In epidemiological studies in humans, there was no evidence of carcinogencity and there were no effects on fertility, reproduction and development or of neurotoxicity that might be attributed to glyphosate. “
In recent years, multiple publications with various levels of scientific rigor have been disseminated concerning the safety of glyphosate (Antoniou et al., 2012; Krüger et al., 2013). Some claim that glyphosate is responsible for all the ailments of the Western world (Samsel and Seneff, 2014). Others simply selectively cite literature on their topic of interest without presenting the scope of information on the topic and assert unwarranted conclusions that do not reflect the body of scientific knowledge. Some have been rejected by the scientific community and retracted by the publishers and are no longer citable. While having a background in toxicology, epidemiology or medicine may be helpful in discerning the quality and integrity of such publications, I suggest the following nontechnical considerations to help make up your own mind on the merits of specific publications.
- Are the authors experienced in this area of research? What is their publication track record?
- Is the publication based on the authors’ own research? If it is cited from elsewhere, dig deeper to see if the primary literature conclusions are actually reflected in the publication at hand.
- Is the publication agenda driven or objective research? Was the publication concomitant with a media campaign and/or book release or followed up with a lecture tour, and, if so, who is funding these activities?
- The scientific process does not stop with a publication. Often, letters to the editor follow; these may offer further insights and opinions but, sadly, are not often linked to the original paper. Dig deeper to find follow-up correspondence on the literature of interest.
- Look for expert review manuscripts on the topic, published in high-quality scientific journals.
- Check the authenticity of the journal as offering quality peer-reviewed scientific literature. Go to Beall’s list (http://scholarlyoa.com/2012/12/06/bealls-list-of-predatory-publishers-2013/) to help discern questionable publishers and journals, which may not provide adequate peer review. Often such journals may not publish letters to the editor.
While I have gone beyond the simple answer “no,” I hope my response has provided you with confidence in the many glyphosate scientific regulatory reviews endorsing the safe and responsible use of glyphosate. I’ve also suggested additional approaches to help increase your confidence in researching and answering similar questions, if you have the time—or you may simply submit more questions to GMO Answers.
David Saltmiras, PhD, DABT
Toxicology Manager, Science Fellow
Antoniou M, Habib MEM, Howard CV, Jennings RC, Leifert C, Nodari RO, Robinson CJ, Fagan J. Teratogenic Effects of Glyphosate-Based Herbicides: Divergence of Regulatory Decisions from Scientific Evidence. J Environ Anal Toxicol S4:006. DOI: 10.4172/2161-0525.S4-006
- APVMA Review of original article internet posting: http://www.apvma.gov.au/news_media/docs/glyphosate_scitox_review_july_2013.pdf
Krüger M, Schrödl W, Neuhaus J, and Shehata AA. Field Investigations of Glyphosate in Urine of Danish Dairy Cows, J Environ Anal Toxicol 2013, 3:5 (an on-line open access journal)
Samsel A & Seneff S. Glyphosate, pathways to modern diseases II: Celiac sprue and gluten intolerance. Interdiscip Toxicol. 2013 vol 6, pp159–184