The Hazards of DEET

Many people want to be safe from West Nile and Lyme Disease, but are wary of products that have DEET and other chemicals in them. With good reason! In this blog post, we explore the toxicity of common bug sprays and why we should avoid them. (Part Two will talk about the sensible alternatives Boline offers.)

“DEET is a good chemical for protection against insects, but prolonged exposure results in neurological damage, and this is enhanced by other chemicals and medications.**” Bahie Abou-Donia of the Duke University -Medical Center (Aug, 2009)

**Interactions with other chemicals: Other studies have shown that combining sunscreen with DEET caused skin to absorb DEET insect repellent more than three times faster than when used alone. This means that products with “safe” or low levels of DEET likely cause long-term neurological damage when used with common sunscreens.  Other studies have shown a 6X more rapid absorption of DEET and 3-4X higher amounts of DEET absorbed by the human body.
(From the journal “Drug Metabolism and Disposition”)  

“DEET should not be used in a product that combines the repellent with a sunscreen. Sunscreens often are applied repeatedly because they can be washed off. DEET is not water-soluble and will last up to 8 hours. Repeated application may increase the potential toxic effects of DEET.” (American Academy of Pediatrics)

And yes the Canadian & US military use DEET, but a 1990’s research program by the US Dept. of Agriculture employee (in Florida) found he could reproduce roughly half of Gulf War Syndrome symptoms by combining DEET with the sunscreen they used during Desert Storm. Strangely, his previous 15 years of accepted research results were all suddenly called into question, he was summarily fired, and the program linking DEET/Pesticides/Sunscreen was immediately terminated. In that politically correct era’s wrangling, his DEET research results were buried and neglected until the early 2000’s when it again became acceptable to question such things.

Did you know?
DEET   (N,N-diethyl-3-methylbenzamide), slows or halts the actions of the enzyme acetylcholinesterase in both insects and mammals. This enzyme is typically found between nerve and muscle cells, breaking down a messenger molecule after it has passed information from one cell to another. If the messenger isn’t properly recycled, it can build up and lead to paralysis.

The American Academy of Pediatrics (AAP) has issued guidelines regarding DEET use in children. It recommends avoiding DEET in children <2 months of age. For all other children, it advises using DEET with a concentration between 10% and 30%.

If you feel that you must use DEET:

  • Apply DEET sparingly on exposed skin; do not use under clothing.
  • Do not use DEET on the hands of young children; avoid applying to areas around the eyes and mouth.
  • Do not use DEET over cuts, wounds or irritated skin. Wash treated skin with soap and water after returning indoors; wash treated clothing.
  • Avoid spraying in enclosed areas; do not use DEET near food.”
    (From The American Academy of Pediatrics:  Follow Safety Precautions When Using DEET)

So why do so many say DEET is the "most effective"? What they mean by that is not only how few bites are sustained, but how few times re-application is needed. As you probably know, natural products that are better for the body and the environment need to be re-applied (such as sunscreen and bug spray). If a manufacturer claims that you don't, chances are there are chemicals in the formula that disrupt the endocrine system or other systems of the body (in the case of DEET, the nervous system).

So what should you use, for you and your family? What is a safer, but effective alternative? Stay tuned for part two!

Sources and Further Reading:
Koren G, Matsui D, Bailey B. DEET-based insect repellents: safety implications for children and pregnant and lactating women. CMAJ 2003;169:209-212. Erratum in: CMAJ 2003;169:283.

Osimitz TG. Murphy JV. Neurological effects associated with use of the insect repellent N,N-diethyl-m-toluamide (DEET). J Toxicol Clin Toxicol. 1997;35(5):443-445.

Ross EA. Savage KA. Utley LJ. Tebbett IR. Insect repellant interactions: sunscreens enhance deet (N,N-diethyl-m-toluamide) absorption. Drug Metabolism & Disposition. 2004; 32(8):783-785, 2004 Aug.

Fradin MS, Day JF. Comparative efficacy of insect repellants against mosquito bites. N Engl J Med 2002; 347:13-18.

YucaLandia/Surviving Yucatan. © Steven M. Fry

Scientific American Article on DEET toxicity

US National Library of Medicine: How to recognize bug repellent poisoning and what to do.

From US Centers for Disease Control (CDC): West Nile Virus: Questions & Answers

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