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How DEET Works

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Some Pyramid repellents use DEET (N, N-Diethyl-meta-toluamide) as their main ingredient and this post gives you essential information on what DEET is and how it works. Read this before you buy and find out what makes DEET the best repellent on the market!

What is DEET?

DEET is an effective and widely used insect repellent. It was first used by the U.S Army in 1946 for soldiers who were working in jungle areas. By 1947, DEET had been approved for public use and has been used ever since.

It has been reviewed and tested as suitable for use by the European Union under the Biocidal Products Regulations (528/2012). We only use ingredients in our products that work.

How it Works?

Insects are attracted to humans by the odours in our sweat or breath, such as lactic acid and carbon dioxide. DEET works as an insect repellent in several different ways.  

It blocks the insect’s olfactory receptors; the “specialised neurons in the sensing pads that protrude from their head”1. Specifically DEET interferes with the receptors picking up 1-octen-3-ol, a volatile substance that is contained in human sweat and breath. In other words, it “blinds” the insect’s sense of smell to the presence of humans and makes it difficult for them to find you.

See our How DEET Works Infographic:

How DEET Works >

How DEET Works

In addition to blocking some of the olfactory receptors in mosquitoes it also reacts with some of the other receptors in a negative way. Mosquitoes and insects intensely dislike the smell of the chemical itself and hence it repels them.

In contrast to insecticides, DEET does not kill insects, it discourages them from landing and/or biting.

Micro-encapsulated DEET

Micro-encapsulated DEET is a special form of the chemical that slows down the release of the repellent vapour, releasing it over a longer period of time. DEET is encapsulated in a shell of a cellulose-alginate blend (otherwise known as a polymethylsilsesquioxane wall). When you move, friction releases a sustained release of repellent vapour.

This means that a lower amount of DEET can be used, to achieve the same performance as higher strength repellents, and it reduces the number of times that you need to re-apply the repellent.

Micro-encapsulated DEET provides long-lasting protection, with lower concentrations of DEET.

Try our Trek Ultra repellent which uses this technology.

What Insects Does DEET Repel?

It has been widely tested to be effective against the following insects, preventing you from getting insect-borne diseases such as West Nile Virus, Malaria and Chikungunya:

  • Mosquitoes
  • Stable flies
  • Black flies
  • Ticks
  • Chiggers
  • Midges
  • Deer flies

Is DEET Safe?

Scientists from the London School of Hygiene and Tropical Medicine have described DEET as “the safest you can get”2. It is regularly tested as suitable for use by scientists and speculation about its safety has never been found to be conclusive. “The 14 cases of DEET-related encephalopathy recorded since 1957 was small compared to the 200 million applications of the repellent across the world every year”2.

DEET repellents help to protect millions of people from life-threatening insect-borne diseases every day, across the world.

Together with a treated mosquito net, a DEET repellent is essential for anyone visiting tropical destinations that have a high risk of Malaria or other insect-borne diseases.

Use biocides safely. Always read the label and product information before use.


  1. New Scientist, “Look to mosquito smell neurons to find new repellents”, December 2013.

  1. BBC News, “Insect Repellent is “safe” to use, scientists say”, June 2014.


Written by Carolyn


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