Overview of glyphosate toxicity and its commercial formulations evaluated in laboratory animal tests

Glyphosate is a broad-sprectrum herbicide widely used to eliminate unwanted plants both in agricultural or urban landscapes. Queries regarding the safety of glyphosate as the main herbicide employed worldwide (and its use in commercial formulations) are a matter of concern periodically raised. This review was undertaken to evaluate the present information regarding toxicity of glyphosate and its major breakdown metabolite (aminomethylphosphonic acid; AMPA) in experimental animal models. Effects of the surfactant polyethoxylated tallow amine (POEA) usually present in registered glyphosate trademarks were also examined. Topics revised in this paper include oral absorption, dermal penetration studies, acute, subchronic, and chronic exposure. Also multiple lifetime feeding experimentation was analyzed in order to evaluate its tumorigenic/carcinogenic potential, endocrine disrupting activity, and fertility and/or reproductive damages. Finally, recent experimental evidence regarding the role of glyphosate on oxidative stress-induced damage was presented and discussed considering doses and administration ways. It was concluded that more exhaustive studies should be performed in certain (specific) areas in order to evaluate appropriately the real impact of this herbicide, and especially its commercial formulations on some aspects of the animal physiology.