Insect Repellent With Deet

Deet, or N,N-diethyl-meta-toluamide is a common insect repellent ingredient that has been on the market since 1957. It was introduced by the US Army as a mosquito repellent. Recent studies have indicated that it may cause problems when used over long periods of time and can have damaging effects to the nervous system. This article breaks down the risks of using Deet and discusses some natural alternatives.

Insect Repellent With Deet

DEET (chemical name, N,N-diethyl-meta-toluamide) is the active ingredient in many repellent products. It is widely used to repel biting pests such as mosquitoes and ticks. Every year, an estimated one-third of the U.S. population use DEET to protect them from mosquito-borne illnesses like West Nile Virus, the Zika virus or malaria and tick-borne illnesses like Lyme disease and Rocky Mountain spotted fever.

Products containing DEET currently are available to the public in a variety of liquids, lotions, sprays, and impregnated materials (e.g., towelettes, roll on). Formulations registered for direct application to human skin contain from 5 to 99% 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 people’s skin to repel insects. Rather than killing them, DEET works by making it hard for these biting bugs to smell us. After it was developed by the U.S. Army in 1946, DEET was registered for use by the general public in 1957. Approximately 120 products containing DEET are currently registered with EPA by about 30 different companies.

Safety Review of DEET

1998 Review

After completing a comprehensive re-assessment of DEET, we concluded that insect repellents containing DEET do not present a health concern. Consumers are advised to read and follow label directions when using any pesticide product, including insect repellents. Based on extensive toxicity testing, we believe that the normal use of DEET does not present a health concern to the general population, including children. We completed this review and issued a reregistration decision (called a RED) in 1998.

2014 Review

In 2014, we completed an interim review of DEET under the Registration Review Program to ensure that it continues to meet safety standards based on current scientific knowledge. The Agency has not identified any risks of concern to human health, non-target species or the environment.

We continue to believe that the normal use of DEET does not present a health concern to the general population, including children. As always, consumers are advised to read and follow label directions in using any pesticide product, including insect repellents. Currently registered uses of DEET are also not expected to result in adverse effects for listed and non-listed endangered species, or critical habitat. As such, EPA concludes “no effect” for listed species and no adverse modification of designated critical habitat for all currently registered uses of DEET.

EPA issued an Interim Decision for DEET in September 2014. We concluded that:

no additional data are required at this time; and
no changes to the affected registrations or their labeling are needed at this time.

The human health risk assessment concluded that there are no risks of concern because no toxic effects have been identified when used as a dermally applied insect repellent, and there is no dietary or occupational exposure for DEET. However, a Final Decision on the DEET registration review case will occur only after the EPA has completed an Endocrine Disruptor Screening under FFDCA section 408(p). Under the Endocrine Disruptor Screening Program, EPA has prioritized chemicals for screening and DEET is lower on the priority list than chemicals currently being tested.

Benefits of DEET Products

DEET’s most significant benefit is its ability to repel potentially disease-carrying insects and ticks. The Centers for Disease Control and Prevention (CDC) receives more than 30,000 reports of Lyme disease (transmitted by deer ticks) and 80-100 reports of La Crosse encephalitis virus (transmitted by mosquitoes) annually. A total of 48 states and the District of Columbia have reported West Nile virus infections in people, birds or mosquitoes to CDC.

Each of these diseases can cause serious health problems or even death in the case of encephalitis. Where these diseases are prevalent, the CDC recommends use of insect repellents when out-of-doors. Studies in EPA’s database indicate that DEET repels ticks for about two to ten hours, and mosquitoes from two to twelve hours depending on the percentage of DEET in the product.

Using DEET Products Safely

FIFRA requires that pesticides be used according to the approved label. Always follow the recommendations appearing on the product label. According to the CDC, DEET products used as directed, should not be harmful, although in rare cases using DEET products can cause skin irritation.

All DEET product labels include the following directions to help reduce the chance of DEET irritating your skin or eyes:

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.