03 Aug 2009

The active ingredient in many insect repellents is DEET – a man-made chemical that been found to be toxic to the central nervous system. Researchers writing in the open access journal, BMC Biology, say that more investigations are urgently needed to confirm or dismiss any potential neurotoxicity to humans, especially when DEET-based repellents are often used in combination with other neurotoxic insecticides.

Vincent Corbel from the Institut de Recherche pour le Développement in Montpellier, and Bruno Lapied from the University of Angers, France, led a team of researchers who investigated the mode of action and toxicity of DEET (N,N-Diethyl-3-methylbenzamide). Corbel said, “We’ve found that DEET is not simply a behavior-modifying chemical but also inhibits the activity of a key central nervous system enzyme, acetycholinesterase, in both insects and mammals”.

DEET -N,N-Diethyl-meta-toluamide is the most common ingredient in commercial insect repellents. A synthetic chemical, developed by the US Army for its use during jungle warfare shortly after WWII and used in Vietnam, South East Asia and recently in the Gulf War.
Please do your own research on the possible hazards of DEET on human beings, especially children and other living organisms. We have provided some links below to illustrate the concerns about and the reasons we have developed the BUG-grrr OFF, DEET-free formulation.

DEET is commonly used in combination with insecticides and can strengthen the toxicity of carbamate insecticides, which are also acetylcholinesterase inhibitors. These findings indicate that DEET has neurological effects on insects in addition to known olfactory effects, and that its toxicity is strengthened in combination with other insecticides.
Moss (1996). “Synergism of Toxicity of N,N-Diethyl-m-toluamide to German Cockroaches (Othoptera: Blattellidae) by Hydrolytic Enzyme Inhibitors”. J. Econ. Entomol. 89 (5): 1151–1155. PMID 17450648.

Citing human health reasons, Health Canada barred the sale of insect repellents for human use that contained more than 30% DEET in a 2002 re-evaluation.

The agency recommended that DEET-based products be used on children between the ages of 2 and 12 only if the concentration of DEET is 10% or less and that repellents be applied no more than 3 times a day, children under 2 should not receive more than 1 application of repellent in a day and DEET-based products of any concentration should not be used on infants under 6 months

Insect Repellents”. Healthy Living. Health Canada. August 2009. Retrieved 2010-07-09.
Jump up ^ “Re-evaluation Decision Document: Personal insect repellents containing DEET (N,N-diethyl-m-toluamide and related compounds)”. Consumer Product Safety. Health Canada. 2002-04-15. Retrieved 2010-07-09

DEET is an effective solvent,[4] and may dissolve some plastics, rayon, spandex, other synthetic fabrics, and painted or varnished surfaces including nail polish.

Though DEET is not expected to bioaccumulate, it has been found to have a slight toxicity for cold water fish such as rainbow trout and tilapia and it also has been shown to be toxic for some species of freshwater zooplankton.
U.S. Environmental Protection Agency. 1980. Office of Pesticides and Toxic Substances. N,N-diethyl-m-toluamide (Deet) Pesticide Registration Standard. December, 1980.
83 pp.Mathai, AT; Pillai, KS; Deshmukh, PB (1989). “Acute toxicity of deet to a freshwater fish, Tilapia mossambica : Effect on tissue glutathione levels”. Journal of Environmental Biology 10 (2): 87–91

The Pesticide Information Project of Cooperative Extension Offices of Cornell University states that “Everglades National Park employees having extensive DEET exposure were more likely to have insomnia, mood disturbances and impaired cognitive function than were lesser exposed co-workers”.
“DEET”. Pesticide Information Profile. EXTOXNET. October 1997. Retrieved 2007-09-26.

Two more chemicals used in some man-made insect repellents are worthy of some further consideration before spraying on humans.
• Di-n-propyl isocinchomeronate
• N-octyl bicycloheptene dicarboximide