Mosquitoes Outsmart DEET Repellents Within 3 Hours

In the same way that many bacteria have learned resistance to antibiotics, mosquitos are learning how to outsmart chemical repellents, according to research in the medical journal Parasites and Vectors, which is a serious concern for mosquito magnets like me.

Additional research conducted by scientists at the Biological Chemistry and Crop Protection Department in Hertfordshire, England, shows that not only are chemical repellents less effective with time, but that amount of time is only about three hours. In the study published in the online medical journal PLoS One, the scientists conducted four sets of experiments including one that involved attaching tiny electrodes to the antenna of mosquitoes, the location where mosquitoes have their sense of smell, and then observing the mosquitoes’ brain wave activity.

The scientists observed that only three hours after the mosquitoes’ first exposure to the chemical repellent N,N-Diethyl-m-toluamide, better known as DEET, there appeared to be almost no further brain activity changes in the mosquitoes. In other words, in the same way humans can become desensitized to things to which we are exposed, so too can mosquitoes. The scientists concluded that their research has “implications for the use of (DEET) repellents and the ability of mosquitoes to overcome them.”

Earlier research reported in Medical Daily by two of the same scientists working on the mosquito electrode study found that some mosquitos have developed a genetic mutation that prevents them from smelling or being negatively affected by chemical insect repellents at all.

DEET-based mosquito repellents are among the most widely-used repellents and while they have been used for decades, present some concerns other than their growing ineffectiveness. Earlier research by Duke University scientists link DEET use to brain cell damage, harmful interactions with some medications, and behavioral changes. The researchers observed brain cell death and behavioural changes in animals exposed to DEET after frequent and prolonged use.

Other research published in the Journal of Toxicology and Environmental Health found that DEET and other pesticide exposure resulted in damage to the blood-brain barrier and brain and nerve cell death. The blood-brain barrier is a mechanism in the body to prevent harmful toxins from gaining access to the delicate brain; however, obviously some chemicals are bypassing this important mechanism.

While many people spray DEET on their skin without consideration of the possible health effects, in reality, whatever goes on the skin tends to be quickly absorbed into the bloodstream where it can circulate throughout the body to the brain or other organs. Not only has a study published in the International Journal of Toxicology find that DEET permeated the skin and bodily tissues, it accumulated in the blood, liver, and brain after repeated topical uses. What’s worse is that the combination of DEET repellents and an ingredient in many sunscreens was found to increase the rate of absorption and deposition in the body. Yet, that is exactly how many people are using these products.

For more information about common products with toxic effects on the body, consult my book Weekend Wonder Detox.



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Siyus Copetallus
Siyus Copetallus3 years ago

Thank you for sharing

Mona M.
Mona M3 years ago

Then we must read the other healthy Living article: Top 5 Natural Mosquito Repellents that Really Work.

Nikki Davey
Nikki Davey3 years ago


Jennifer H.
Jennifer H3 years ago

Cedar F. That is what I got out of the article too! Scary on both fronts. Thanks for the info.

Elena Poensgen
Elena Poensgen3 years ago

Thank you

David Thieke
David Thieke3 years ago

Thanks for the info !

Winn Adams
Winn Adams3 years ago


Sen Senz
Sayenne H3 years ago

Smart little creatures

Pat P.
Pat P3 years ago

Nothing ever works for me against mosquitoes except the extra strength Deet products. I have tried all sorts of herbal remedies, including Avon's Skin So Soft. I can be outside my house for only 1/2 hour and get bitten on average 15 times! So now, if I don't want to spray, I wear a mesh mosquito jacket. It can get really hot inside this thing, but it's better than being bitten over and over--no matter what time of day or what part of the summer. If any part of my body is not covered, even parts of my face, the little buggers get me!

Cedar F.
Past Member 3 years ago

Are you saying that DEET is harmful to humans but does not affect mosquitoes?