The world-wide dominant herbicide contains compounds more toxic than expected as new research shows

PR 01/13 The world-wide dominant herbicide contains compounds more toxic than expected as new research shows

Zusatzstoffe des weltweit bedeutendsten Herbizids sind deutlich toxischer als erwartet – Jüngste Forschungsergebnisse aus Frankreich publiziert

Le principal herbicide du monde contient des substances plus toxiques que prevu – une nouvelle recherche le demontre

Una nueva investigatión demuestra que el herbicida más usado en todo elmundo contiene componentes más tóxico de lo inicialmente esperado

Caen, 21. 02. 2013 – A new study published in the high-ranked scientific journal “Toxicology” by Robin Mesnage, Benoît Bernay and Professor Gilles-Eric Séralini (University of Caen, France) (1) proofs that the most toxic compound in nine glyphosate-containing herbicides is not glyphosate but a compound called POE-15. This polyethoxylated tallowamine functions as adjuvant. The herbicide labels do not mention POE-15 on a regular basis. Mass spectrometry was applied to identify the structure of this additional chemical. Modern methods at the cellular level used on three human cell lines were used to analyse the toxicological effects of POE-15.

Context: Glyphosate is the “active ingredient” of Roundup, the major herbicide in the world; it is present in a large family of herbicides. But the “formulation” as which it is sold to the farmers contains additional chemicals e.g. adjuvants. The exact composition of the marketed herbicide is classified as confidential and the adjuvants are often characterised to be toxicologically “inert”. They are used to stabilize the chemical compound glyphosate and enable its penetration into the plants’ tissue. The adjuvants dissolve the waxy surface of plants and the membranes of living cells. Therefore, such “formulations” can affect all living cells, also human ones. This difference is often overlooked because glyphosate and the final products as e.g. Roundup are used as synonyms. The supposed non-toxicity of the active ingredient is taken as the basis to declare the commercial use of the herbicide as safe. The health and environmental agencies as well as the pesticide companies assess the effects – short- to long-term – of pure glyphosate on mammals, but not the effects of the “formulations”. Details and data of these regulatory assessments are strictly kept confidential upon request by companies like Monsanto.

Conclusion and Demands: This study by CRIIGEN, an institutional member of the European Network of Scientists for Social and Environmental Responsibility (ENSSER), (2) demonstrates that all analysed Roundup-like herbicides are more toxic than glyphosate alone and provides a conclusive explanation for this observation. Thus the current regulatory assessments and the maximal residue levels authorized for the environment, food and feed, appear to be deficient. Liquids (such as tap water contaminated by Roundup) or food derived from Roundup-tolerant GM plants were already demonstrated as toxic in a recent rat nutritional study by the team of Prof. Séralini in 2012 (3). In combination with a recently published reply to the critics of the 2012 paper (4), this new study explains and confirms the results of Séralini et al. (2012).

Overall, these research results create a great concern for public health. Not only all authorizations of Roundup-like herbicides have to be called into question, but also the assessment methods and procedures have to be revised fully. This revision needs to be undertaken in a transparent manner including the variety of existing positions in the scientific community. Risk assessment panels and agencies were so far following the conclusion of Monsanto with regard to the safety of the products. These decisions need to be challenged based on their laxity and confidentiality practices avoiding full and transparent assessments. The neutrality and independence of these bodies in the context of the necessary re-evaluation is highly questionable. Therefore, a first step in the re-evaluation would be the on-line presentation of all data and assessments concerning the commercialisation of such herbicides to the public. Access to full information on health effects of pesticides needs to be guaranteed by law.

Adjuvants of the POE-15 family can be qualified as new active ingredient of herbicides with regard to the toxicity on human cells. They have to be regulated as such with the appropriate toxicity tests. We call for a revision of the approval process for the fully formulated pesticides as sold on the market and released into environment including long-term toxicity tests. Moreover, since products with confidential compositions including toxic adjuvants are widely used, we fear that the real toxicity of these products has been strongly underestimated unless new scientific research unveils such toxic properties.

Contact: CRIIGEN, University of Caen
P +33 (0)2 31 565684

The European Network of Scientists for Social and Environmental Responsibility (ENSSER) brings together independent scientific expertise to develop public-good knowledge for the critical assessment of existing and emerging technologies. The objective of ENSSER is the advancement of public-good science and research for the protection of the environment, biological diversity and human health against adverse impacts of new technologies and their products. ENSSER advocates benign and peaceful use of scientific discoveries and technological developments, while expanding diverse approaches to assess their utility and safety in society. More information available at:

Notes for editors:
1) Mesnage et al. 2013, Ethoxylated adjuvants of glyphosate-based herbicides are active principles of human cell toxicity, available at:

2) ENSSER, 2012, Questionable Biosafety of GMOs, Double Standards and, Once Again, a ‘Shooting-the-Messenger’ Style Debate, available in English, Spanish, and Chinese (Mandarin) at

3) Séralini et al., 2012, Long term toxicity of a Roundup herbicide and a Roundup-tolerant genetically modified maize, available at

4) Séralini et al., 2013, Answers to critics: Why there is a long term toxicity due to a Roundup-tolerant genetically modified maize and to a Roundup herbicide, available at