A recent in vitro study by in international team of researchers shows that DEET, the World’s most commonly used ingredient in insect repellents, has a toxic effect on the nervous system of insects and mammals.

“N,N-Diethyl-3-methylbenzamide [1] (DEET) remains the gold standard for insect repellents. About 200 million people use it every year and over 8 billion doses have been applied over the past 50 years,” say the authors of the study, which was published online by BioMed Central Biology.

N,N-Diethyl-3-methylbenzamide, ou simplement, DEET

Researchers have investigated the molecular target site for DEET and the consequences of its interactions with carbamate insecticides on the cholinergic system. By using toxicological, biochemical and electrophysiological techniques, they showed that DEET is not simply a behaviour-modifying chemical but that it also inhibits cholinesterase activity, in both insect and mammalian neuronal preparations. Cholinesterase activity is key in the communication between nervous cells.

The authors say their findings “question the safety of DEET, particularly in combination with other chemicals, and they highlight the importance of a multidisciplinary approach to the development of safer insect repellents for use in public health”.