Mosquitoes are attracted to moisture, warmth, body odor, and exhalation of carbon dioxide. Hence human beings attract mosquitoes.

Most mosquito repellants don't technically "repel" mosquitoes; they block the receptors on mosquitoes' antennae for the aspects of human beings. Although many home remedies and oddball uses of everyday products do serve to repel mosquitoes somewhat, they don't work very effectively for very long. If you are worried about West Nile, use a product that contains DEET rather than trying used dryer sheets, VapoRub, vanilla, frogs, marigolds, or any other item touted by your friends.

A wide range of products claim their effectiveness in repelling mosquitoes, but most insect repellants containing herbal oils are far less effective than those containing DEET.

DEET (chemical name, N,N-diethyl-meta-toluamide) is the active ingredient in many insect repellent products. It is used to repel biting pests such as mosquitoes and ticks, including ticks that may carry Lyme disease. Every year, approximately one-third of the U.S. population is expected to use DEET. Products containing DEET currently are available to the public in a variety of liquids, lotions, sprays, and impregnated materials (e.g., wrist bands). Formulations registered for direct application to human skin contain from 4 to 100% DEET. Except for a few veterinary uses, DEET is registered for use by consumers, and it is not used on food.

DEET is designed for direct application to human skin to repel insects, rather than kill them. After it was developed by the U.S. Army in 1946, DEET was registered for use by the general public in 1957. Approximately 140 products containing DEET are currently registered with EPA by about 39 different companies.

DEET's most significant benefit is its ability to repel potentially disease-carrying insects and ticks. The Centers for Disease Control (CDC) receives more than 20,000 reports of Lyme disease (transmitted by deer ticks) and 100 reports of encephalitis (transmitted by mosquitoes) annually. Both of these diseases can cause serious health problems or even death in the case of encephalitis. Where these diseases are endemic, the CDC recommends use of insect repellents when out-of-doors. Studies submitted to EPA indicate that DEET repels ticks for about three to eight hours, depending on the percentage of DEET in the product.

Safety Review of DEET

A safety review of DEET was completed in 1998. After completing a comprehensive re-assessment of DEET, EPA concluded that, as long as consumers follow label directions and take proper precautions, insect repellents containing DEET do not present a health concern. Human exposure is expected to be brief, and long-term exposure is not expected. Based on extensive toxicity testing, the Agency believes that the normal use of DEET does not present a health concern to the general population. EPA completed this review and issued its reregistration decision (called a RED) in 1998.

How to use DEET products safely

Consumers can reduce their own risks when using DEET by reading and following products labels. All DEET product labels include the following directions:


Read and follow all directions and precautions on this product label.
Do not apply over cuts, wounds, or irritated skin.
Do not apply to hands or near eyes and mouth of young children.
Do not allow young children to apply this product.
Use just enough repellent to cover exposed skin and/or clothing.
Do not use under clothing.
Avoid over-application of this product.
After returning indoors, wash treated skin with soap and water.
Wash treated clothing before wearing it again.
Use of this product may cause skin reactions in rare cases.

The following additional statements will appear on the labels of all aerosol and pump spray formulation labels:
Do not spray in enclosed areas.
To apply to face, spray on hands first and then rub on face. Do not spray directly onto face.

DEET is approved for use on children with no age restriction. 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 EPA to believe there is a need to restrict the use of DEET. Consumers are always advised to read and follow label directions in using any pesticide product, including insect repellents.

If you suspect that you or your child is having an adverse reaction to this product, discontinue use of the product, wash treated skin, and call your local poison control center or physician for help. If you go to a doctor, take the repellent container with you.
Source: U.S. Environmental Protection Agency

Footnote: Researchers in the Vanderbilt University have discovered a new compound, called VUAA1, that repels mosquitoes. In preliminary tests with mosquitoes, they have found that VUAA1 is thousands of times more effective than DEET.
Source: Science Daily