DEET and Permethrin: What’s the Difference?

Although we don’t want ourselves or our kids to be smothered in insect repellent, sometimes, we just need to use repellent creams or sprays for protection. There are just too many insects out there that are vectors of serious diseases. Ticks and mosquitoes, for instance, can transmit several types of virulent viruses and also parasites. Hence, protection is essential, particularly if we’re going to be spending some time outdoors.

DEET and Permethrin

There are many kinds of synthetic insect repellents available these days. Two of the most common are – DEET and permethrin. Many people think that these are the same and can be used interchangeably. To clarify, these two forms of repellents are NOT the same. One cannot be used as a substitute for the other. But they do complement each other.


DEET or diethyl toluamide is a component of many topical insect repellents. In case you’re using a DEET-based repellent, try to use the stuff sparingly. If you’re going outdoors, wear long sleeved tops and pants so that you’ll only need to apply the repellent lotion on a small area of exposed skin. DEET should not be applied near the eyes and mouth. It is also important to avoid putting on DEET on the hands of small children who have a tendency to put their hands in their mouths all the time.


Permethrin contains pyrethroids, which are derived from chrysanthemum flowers. It is not used as a topical insect repellent. Permethrin is and should only be applied onto clothes or hiking or camping gear, like bed nets, tent walls, or boots. The substance must be sprayed on the outer part of clothing or gear, and it must not be sprayed on the inner portion because this section touches the skin. Clothes that have been sprayed with the chemical must be washed separately from other items. Furthermore, permethrin must be allowed to dry completely on garments before these should be worn.

Using DEET and Permethrin

Insect repellents contain different concentrations of DEET. Those with 20% DEET last longer. When using DEET-based products, always follow what’s stated on the label. For example, some insect repellent lotions need to be reapplied every 3 or 4 hours. But there are also others that last for more than 6 hours. As for permethrin, clothing must be pre-treated before wearing. Do not spray permethrin on clothes that you currently have on. When spraying, hang clothes outdoors and spray. Allow these to dry completely. Generally, permethrin-treated clothes last for 2 weeks. This means that you do not need to treat your clothes every day.

In case you’re going hiking or camping, it’s recommended that you pre-treat your gear and garments before your outdoor activities. Once you’re already wearing permethrin-treated clothes, make sure to protect exposed skin as well. This is when you’ll need to use DEET. Apply DEET-based lotions on exposed skin, like the neck or forearms. Make sure that you’re wearing a hat to protect your head from insects. Tuck your pants inside your socks too so that bugs won’t be able to crawl inside your shoes.


Claire Brent is a freelance blogger who writes for and other pest control websites. Preventive Pest Control is a company that can help you with pest prevention and management.