Mosquito Repellent

When used properly, mosquito repellent helps reduce exposure to bites that could lead to diseases such as the West Nile virus. A wide variety of products are available for repelling mosquitoes. Of the active ingredients registered with the EPA as mosquito repellents, two have demonstrated a higher degree of effectiveness: DEET and picaridin. When using one of these products, apply it only to exposed skin or clothing (as directed on the product label).

 

An Introduction to Mosquito Repellent

Mosquito repellent helps reduce your exposure to mosquito bites. Not only can these bites cause an annoying, red itchy bump -- mosquitoes also may carry diseases, such as West Nile virus, that in some cases can be deadly. Mosquito repellents allow you to continue to play, work, and enjoy the outdoors with a lower risk of disease.
 

When Should You Use Mosquito Repellent?

You should use mosquito repellent when you go outdoors, even if you're only going outside for a few minutes. It only takes one mosquito bite to get a serious illness.
 
Many of the mosquitoes that carry diseases bite between dusk and dawn. If you're outside during these hours, pay special attention to using mosquito repellent.
 

Best Mosquito Repellents

A wide variety of mosquito repellent products are available. It is recommended to use products containing active ingredients which have been registered with the U.S. Environmental Protection Agency (EPA) for use as repellents applied to skin and clothing.
 
When the EPA registers a mosquito repellent, the agency evaluates the product for effectiveness and potential effects on human beings and the environment. EPA registration means that the EPA does not expect a repellent, when used according to the instruction label, to cause unreasonable adverse effects to human health or the environment.
 
Of the active ingredients registered with the EPA as mosquito repellents, two have demonstrated a higher degree of effectiveness. Mosquito repellents containing these active ingredients typically provide longer-lasting protection than others:
 
  • DEET (N,N-diethyl-m-toluamide)
  • Picaridin (KBR 3023).
     
Oil of lemon eucalyptus [p-menthane 3,8-diol (PMD)], a plant-based repellent, is also registered with the EPA. In two recent scientific publications, when oil of lemon eucalyptus was tested against mosquitoes found in the United States, it provided protection similar to repellents with low concentrations of DEET.
 
These recommendations are for domestic use in the United States. Mosquito repellent recommendations when traveling outside the United States may differ.
 
In addition, certain mosquito repellents which contain permethrin are recommended for use on clothing, shoes, bed nets, and camping gear, and are registered with the EPA for this use. Permethrin is highly effective as an insecticide and as a mosquito repellent. Permethrin-treated clothing repels and kills ticks, mosquitoes, and other arthropods and retains this effect after repeated laundering. The permethrin insecticide should be reapplied following the label instructions. Some commercial products are available pretreated with permethrin. Permethrin is not to be used directly on skin.
 

Reapplying Mosquito Repellents

You should follow the directions for the specific product you are using in order to determine how often to reapply. Sweating or getting wet may mean that you need to reapply more frequently.
 

Mosquito Repellents and Percentages

In general, the more active ingredient (higher percentage) a mosquito repellent has, the longer a repellent will protect you from mosquitoes. For example, DEET products are available in many formulations -- a product with 30 percent DEET will protect you longer than one with 5 percent DEET.
 
Here are some general tips on applying mosquito repellent:
 
  • For many hours outside (over three to four hours) or where biting is very intense -- look for a repellent containing more than 20 percent DEET. Mosquito repellents with more than 50 percent DEET do not offer additional protection.
     
  • For shorter periods of time, use repellents containing less than 20 percent DEET. There are other products that are also available.
     
Use your common sense. Reapply mosquito repellent if you start to get bitten and follow the label instructions.
 

Mosquito Repellent Safety

There are some general considerations for using mosquito repellent safely. Some of these considerations include:
 
  • Always following the instructions on the product label.
     
  • Applying mosquito repellent only to exposed skin and clothing (as directed on the product label.) Do not use repellents under clothing.
     
  • Never using repellent over cuts, wounds, or irritated skin.
     
  • Never applying to eyes or mouth, and applying sparingly around ears. When using sprays, do not spray directly on face -- spray on hands first and then apply to face.
     
  • Not allowing children to handle mosquito repellent. When using on children, apply to your own hands first and then put it on the child. You may not want to apply to children's hands.
     
  • Using just enough mosquito repellent to cover exposed skin and clothing. Heavy application and saturation are generally unnecessary for effectiveness. If biting insects do not respond to a thin film of repellent, then apply a bit more.
     
  • After returning indoors, washing treated skin with soap and water, or bathing. This is particularly important when mosquito repellents are used repeatedly in a day or on consecutive days. Also, wash treated clothing before wearing it again. (This precaution may vary with different repellents -- check the product label.)
     
  • Discontinuing use of the mosquito repellent if you or your child gets a rash or other bad reaction. Then, wash the repellent off with mild soap and water, and call a local poison control center for further guidance. If you go to a doctor because of the repellent, take the repellent with you to show the doctor.
     
  • Noting that the label for products containing oil of lemon eucalyptus specifies that they should not to be used on children under the age of three years.
     
The EPA does not recommend any other precautions (besides the ones listed above) for using registered mosquito repellents on pregnant or lactating women, or on children.
 
DEET-based mosquito repellents applied according to label instructions may be used along with a separate sunscreen. No data are available at this time regarding the use of other active mosquito repellent ingredients in combination with a sunscreen.
 

Mosquito Repellent and Children

Repellent products must state any age restriction. If there is none, the EPA has not required a restriction on the use of the product.
 
According to the label, oil of lemon eucalyptus products should NOT be used on children under three years of age.
 
DEET is approved for use on children over two months old. There is no restriction on the percentage of DEET in the product for use on children, since data do not show any difference in effects between young animals and adult animals in tests done for product registration. There also are no data showing incidents that would lead the EPA to believe there is a need to restrict the use of DEET.
 

Other Mosquito Precautions

In addition to using mosquito repellent, you can protect yourself and your family by taking these precautions:
 
  • Wear clothing with long pants and long sleeves while outdoors. Apply permethrin or another EPA-registered repellent to clothing, as mosquitoes may bite through thin fabric. (Remember: don't use permethrin on skin.)
     
  • Use mosquito netting over infant carriers.
     
  • Reduce the number of mosquitoes in your area by getting rid of containers with standing water that provide breeding places for the mosquitoes.
     
(Click Preventing Mosquito Bites for more information about mosquito bite prevention.)
 
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Written by/reviewed by: Arthur Schoenstadt, MD
Last reviewed by: Arthur Schoenstadt, MD