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CRUCIAL PAPER 62: Co-formulants of glyphosate herbicides are endocrine disruptors

Date Added to website 29th February 2016


CRUCIAL PAPER 62: Co-formulants of glyphosate herbicides are endocrine disruptors

New research shows regulatory “safe” limits for glyphosate may not be safe at all

The approval process for glyphosate herbicide is disputed because the commercial herbicide formulations as sold and used contain additives or co-formulants, which are more toxic than glyphosate alone. Yet glyphosate alone is tested to calculate the ADI or acceptable daily intake, the level that is supposedly safe to consume over the long term. That's in spite of the fact that we are exposed to the formulations, not the isolated presumed active ingredient glyphosate.

A new study shows that the acceptable daily intake (ADI), the supposedly safe level, for glyphosate is unreliable in terms of assessing the risks of the complete commercial formulations that we are actually exposed to.

The co-formulants were shown in the new study to have a far more powerful endocrine-disrupting effect at lower doses than the isolated active ingredient, glyphosate.

The complete formulations were also found to have much greater endocrine disrupting effects at lower doses than glyphosate alone.

The research shows that the ADI should be calculated from toxicity tests on the commercial formulations as sold and used.

In the new study, published in the International Journal of Environmental Research and Public Health, the researchers measured the endocrine disruptive effects of the co-formulants of six glyphosate herbicides. They measured the activity of aromatase, a key enzyme for the balance of sex hormones, in human placental cells, using a method validated by the OECD to assess endocrine disruptors. 

The aromatase activity was significantly decreased both by the co-formulants alone and by the formulations, from doses 800 times lower than the agricultural dilution. But glyphosate alone only showed such an effect from one-third of the agricultural dilution (in other words, glyphosate was much less of an endocrine disruptor than the co-formulants and the formulations).

According to a press release distributed by the research group CRIIGEN, which supported the work, the new study is the first ever demonstration that the endocrine-disrupting effects of glyphosate-based herbicides are not only attributable to glyphosate, the declared active ingredient, but above all to the co-formulants.

(Source: CRIIGEN)


"Co-Formulants in Glyphosate-Based Herbicides Disrupt Aromatase Activity in Human Cells below Toxic Levels"
by Nicolas Defarge, Eszter Takács, Verónica Laura Lozano, Robin Mesnage, Joël Spiroux de Vendômois, Gilles-Eric Séralini, and András Székács 
International Journal of Environmental Research and Public Health 2016, 13, 264
doi:10.3390/ijerph13030264 (open access)


Pesticide formulations contain declared active ingredients and co-formulants presented as inert and confidential compounds. We tested the endocrine disruption of co-formulants in six glyphosate-based herbicides (GBH), the most used pesticides worldwide. All co-formulants and formulations were comparably cytotoxic well below the agricultural dilution of 1% (18–2000 times for co-formulants, 8–141 times for formulations), and not the declared active ingredient glyphosate (G) alone. The endocrine-disrupting effects of all these compounds were measured on aromatase activity, a key enzyme in the balance of sex hormones, below the toxicity threshold. Aromatase activity was decreased both by the co-formulants alone (polyethoxylated tallow amine—POEA and alkyl polyglucoside—APG) and by the formulations, from concentrations 800 times lower than the agricultural dilutions; while G exerted an effect only at 1/3 of the agricultural dilution. It was demonstrated for the first time that endocrine disruption by GBH could not only be due to the declared active ingredient but also to co-formulants. These results could explain numerous in vivo results with GBHs not seen with G alone; moreover, they challenge the relevance of the acceptable daily intake (ADI) value for GBHs exposures, currently calculated from toxicity tests of the declared active ingredient alone.