DEET Is Harmful to Cells in Lab Settings. What's the Significance?

By Allison Bond | August 5, 2009 4:36 pm

DEETPowerful bug repellant DEET may do more than keep mosquitoes and other biting critters at bay–it might cause neurological damage in mammals, according to a study published in BioMed Central Biology.

Developed in 1946 by the U.S. Army, DEET has been used by the public for more than half a century to repel bugs like mosquitoes, along with the diseases they can carry. The new study, however, shows that DEET—aka N,N-diethyl-meta-toluamide—may be harmful for a variety of animal cells. In lab tests, it caused damage to mosquitoes, cockroach nerves, mouse muscles, and enzymes purified from fruit flies and humans. Applications of DEET slowed or halted the actions of the enzyme acetylcholinesterase. This enzyme hangs out between nerve and muscle cells, breaking down a messenger molecule after it has passed information from one cell to another. If this messenger isn’t properly recycled, it can build up and lead to paralysis [Science News].

Although the findings certainly raise questions about the safety of DEET, further testing is required before scientists will really know what, if any, effect DEET has on the human nervous system. “The experiments that were conducted were mainly done on insects or on individual cells in test tubes, and generally not under conditions that accurately reflect how DEET is used as an insect repellent in the real world. This makes it very difficult if not impossible to interpret the relevance of their findings to human” [BBC News], said pesticide expert Daniel Sudakin. The Environmental Protection Agency plans to further investigate the safety of DEET and will include the findings in its review of the chemical, which is slated for 2012.

Until then, experts advise people to only use enough repellent to cover exposed skin or clothing and caution that repellent should not be applied to cuts, wounds or irritated skin [BBC News]. They also say that because the majority of DEET users apply the repellent infrequently, the risk of damage is quite low. Said malaria expert Brian Greenwood, “Deet has been used for decades with few reported side effects. And the findings of animal studies do not always match what happens in humans” [BBC News].

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Image: flickr /ingserban

CATEGORIZED UNDER: Health & Medicine, Living World
  • NewEnglandBob

    mmmmm, DEET. Brain damage. Yum.

  • sammy

    autism link ????

  • Wesley

    What about those of us with children who live in the tropics where use is NOT infrequent?

  • robot makes music

    “Deet has been used for decades with few reported side effects.”

    But, as they say, use is infrequent – if it has a bioaccumulative effect, the damage would be subtle and take years to effect – a mystery illness.

  • Jimbo

    “Deet has been used for decades with few reported side effects.”
    I like how he doesn’t list the side effects, mostly noted in children: seizures, tremors, vomiting, nausea, and chronic musculoskeletal pain.

  • uncle phil

    i use deet deepwoods off every time i go outside on my ranch in the santa cruz, ca, mountains…when plants are accidently sprayed, they brown out similar to roundup…BUT, it’s the only thing that works, as i get swollen & nasty bites if i don’t use it, then it’s benadryl cocktails…

  • Charles Zigmund

    I’ve used natural insect sprays made with citronella and other ingredients all my long life and have never been bothered by insects. Look in your health foods store for these products. If they don’t work, you can always fall back on DEET.

  • Gloria

    Well, even though it doesn’t have too many reported cases of side effects, you can still try something else; like a blend of cilantro and water, strain through a cheesecloth, and use the liquid like a repellent… a more healthy option.( book resource: “New choices in Natural Healing” Edited by Bill Gottlieb)

  • Paul

    I found these guys in a store in Ontario this stuff really works. I have turned about 15 and counting of my friends to use this soap it’s unreal, I love it and it also works as a after bite too. Skeet soap inc. check it out. Great for kids !

    Paul Skubik

  • eagle

    It is really helpful for me to understand DEEF.


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