Did you know that insect repellents are pesticides? According to pesticide law, a pesticide is any substance or mixture of substances intended for:

• preventing;
• destroying;
• repelling; or
• mitigating any pest. (Mitigating means reducing the effect of something.)

​People often think of the term pesticide as referring only to something that kills insects, but "pesticide" is a broad term and includes products that don't kill anything, such as insect repellents. Products labeled as repellents are not designed to eliminate pests. For example, in the case of the skin-applied repellents, the product makes people less attractive to the pest.

Types of Insect Repellents

Insect repellents applied to the skin are often what we think of when we want to avoid insect bites. These are the most broadly useful, since they stay with you regardless of your movements. Other types of repellents that EPA registers include:

• Clip-on products that have a pad with the repellent and a fan or other mechanism that disperses the repellent near your body.
• Spatial repellents use a heating mechanism to disperse repellent in an outdoor area. Examples of dispersal mechanisms for spatial repellents include:
  • Lanterns.
  • Torches.
  • Table-top diffusers.
  • Candles.
  • Coils.

Note that both stationary and wearable spatial repellents are for outdoor use only, unless the label specifically states they can be used indoors. Read the label to understand any limitations such as:

• The area they cover.
• The effect of wind on their use.
• Whether or not the repellent needs to build up in an area before mosquitoes will be repelled effectively.

To be registered by EPA, these products must have safety and effectiveness data, which EPA evaluates before allowing them on the market.

Other products on the market, such as devices that rely on sound waves, are not registered by EPA, so no safety or effectiveness data are available, and EPA does not know if they will be effective against mosquitoes. They may be subject to certain regulatory requirements as "devices."

Insect repellents can help reduce the risk of mosquito and tick bites, which can transmit diseases. Diseases carried by mosquitoes include:

• Zika
• West Nile Virus
• Malaria
• Encephalitis (several types)
• Yellow fever
• Dengue fever
• Chikungunya virus

Ticks carry diseases such as:

• Lyme disease
• Rocky Mountain Spotted Fever
• Ehrlichiosis
• Encephalitis

The following are active ingredients in EPA-registered skin-applied insect repellents:

• Catnip oil (Nepeta cataria, also known as catmint) (4 products)
• Oil of citronella (3 registered products; also used in unregistered products that meet the requirements for exemption from registration)
• DEET (more than 500 products)
• IR 3535 -- EPA pesticide regulatory information (3-[N-Butyl-N-acetyl]-aminopropionic acid, ethyl ester) (about 45 products)
• p-Menthane-3,8-diol (pmd) (6 products)
• Oil of Lemon Eucalyptus (contains pmd, but is a separately regulated pesticide chemical) (6 products)
• Picaridin (about 40 products)
• 2-undecanone (or methyl nonyl ketone) (1 product)

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. Read the CDC factsheet on DEET.

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.

Using DEET on Children

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.

EPA continues 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.

What to Do in the Event of an Apparent Reaction to DEET

If you suspect that you or your child is having an adverse reaction to a DEET 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.

WHAT TO KNOW

• Nootkatone is an active ingredient that can be used for developing insect repellents and insecticides.
• Environmental Protection Agency (EPA) registration paves the way for manufacturers to develop nootkatone-based products for consumers to buy, including repellents, lotions, and soaps.

Overview

Every state and U.S. territory is at risk for vector-borne diseases (VBDs). The number of reported VBD cases doubled from 2004 to 2018. Tickborne diseases represent almost 80 percent of reported VDB cases in the contiguous United States. Ten vector-borne pathogens were newly identified in the United States in the past 16 years, including chikungunya virus, Zika virus, and six tickborne pathogens.

For various reasons, many people don’t like to use insect repellents. To address mosquito- and tickborne disease threats, products that people accept and are willing to use to protect themselves from bites are needed. In addition, mosquitoes are becoming increasingly resistant to insecticides. New publicly supported insecticide options are necessary.

On July 20, 2020 the EPA announced registration of nootkatone for manufacturing use into insecticides and repellents. CDC was instrumental in early efforts to demonstrate that nootkatone can repel and kill arthropod vectors, including mosquitoes and ticks. Building on CDC's earlier work, a collaboration between CDC, the HHS Biomedical Advanced Research Development Authority, and an industry partner, Evolva, resulted in EPA registration of nootkatone as a biopesticide. This makes possible the development of nootkatone-based products targeting mosquitoes and ticks. CDC and Evolva jointly own patents for the use of nootkatone to repel and kill arthropod pathogen vectors.

About nootkatone

• A compound found in minute quantities in Alaska yellow cedar trees and grapefruit skin.
• Able to repel and kill ticks and insects, including mosquitoes.
• Responsible for the characteristic smell and taste of grapefruit.
• Widely used in the food industry to flavor foods.
• Widely used in the fragrance industry to make perfumes and colognes.
  • Lasts on skin and clothing for several hours.
  • Currently used in citrus-smelling shampoos, conditioners, and lotions.

It takes several tons of grapefruit to produce just 1 kg (2.2 lb.) of nootkatone. Evolva’s manufacturing process allows nootkatone to be made in large amounts in a consistent and contaminant-free manner. Once rare and expensive, nootkatone is now being produced at a low cost.

Nootkatone is an active ingredient

• Nootkatone is an active ingredient. It is not an end-use (brand name) product.
• Active ingredients are what make end-use products effective.
• As an example, DEET is an active ingredient that is used in many brand name insect repellents.

Novel mode of action

• Nootkatone appears to kill biting pests in a unique way, different from other insecticides already registered by the EPA, including pyrethroids, organophosphates, carbamates, and cyclodienes.
• Insecticides made with nootkatone may help in the fight against mosquitoes that have become resistant to existing insecticides.

Photos

Factory-Treated Clothing to Repel Insects

The only insect repellent currently used for factory treatment of clothing is permethrin. Permethrin is a broad spectrum, non-systemic, synthetic pyrethroid insecticide that targets adults and larvae of many species of biting, chewing, scaling, soil, and flying invertebrates. Permethrin is registered by the EPA as an insecticide for use in a variety of settings. When used to pre-treat clothing, it is an insect repellent.

Permethrin has been registered since 1979. It was first registered in 1990 for use as a repellent on clothing by the military. At about the same time, we also approved permethrin as a spray for use on clothing and gear by consumers, as well as for commercial factory treatment of clothing and various types of gear. In 2003, we first registered consumer-oriented, permethrin factory-treated clothing products. More products have been approved since then.

Safety of Permethrin in Factory-Treated Clothing

When evaluating these products in the pesticide registration process, we follow normal risk assessment procedures to determine safety. Our 2009 revised exposure and risk assessment evaluated multiple exposure scenarios for permethrin factory-treated clothing, including toddlers wearing or mouthing the clothing, and military personnel who wear permethrin-treated uniforms on a daily basis. All exposure scenarios showed that permethrin factory-treated clothing is unlikely to pose any significant immediate or long-term hazard to people wearing the clothing.

The amount of permethrin allowed in clothing is very low, and scientific studies indicate that human exposure resulting from wearing permethrin factory-treated clothing also is low. Available data show that permethrin is poorly absorbed through the skin.

Women Who are Pregnant or Nursing

Based on our review of scientific studies, there is no evidence of reproductive or developmental effects to mother or child following exposure to permethrin.

Safe Use: Follow the Label

Clothing factory-treated with permethrin is considered a pesticide product, and as with any pesticide product, it must be marketed with a pesticide use label. The pesticide use label on such clothing is in the form of a "hang-tag,” which is typically attached to the outside of the clothing. As with any pesticide product, consumers must follow the directions and precautions on the "hang-tag" label that accompanies this clothing.

Use of Factory-Treated Clothing in Conjunction with Insect Repellents

When wearing permethrin factory-treated clothing to repel insects, only the skin surface covered with the factory-treated clothing is protected from the pests listed on the label. Treat other exposed parts of the body with an insect repellent labeled for use on human skin for more complete protection.

Why the Label Calls for Washing Clothes Separately

Small amounts of permethrin can come off in the wash, as shown by available scientific studies. Only outer clothing is treated with permethrin, as outer clothing is most likely to come into direct contact with the listed pests. Permethrin repellent products used for factory-treatment of clothing or as spray-ons for clothing are not to be applied to certain clothing such as underwear. For this reason, the label instructs consumers to wash permethrin-treated clothing separately from non-treated clothing.

Effectiveness of Factory-Treated Clothing

We require manufacturers of all pesticides to provide data demonstrating that the product will work to control pests as claimed on the label. In the case of pests of public health concern, such as mosquitoes and ticks, the manufacturer must submit these efficacy studies for review and approval by EPA. We have reviewed these data for permethrin factory-treated clothing and found that the clothing is effective in repelling target pests.

Meaning of EPA Registration and Status of Permethrin

Federal law requires that before selling or distributing a pesticide in the United States, a person or company must obtain a registration, or license, from EPA. Before registering a new pesticide or new use for a registered pesticide, we must first ensure that the pesticide, when used according to label directions, meets the safety standard set by law.

In evaluating pesticides for registration, we require the manufacturers to provide a variety of studies on the health and environmental effects of each chemical and product. We use these studies to decide whether a product and its intended uses meet our safety standard and whether specific use restrictions are warranted for the safe use of the product. As part of the review and risk assessment process, we consider individuals of varying ages who could be exposed to a pesticide under different use scenarios.

We periodically reevaluate all registered pesticides to ensure continued compliance with current scientific and safety standards.

• We completed the most recent comprehensive human health risk assessment for all registered uses of permethrin in February 2006 in support of the pesticide’s reregistration.
• In revising this assessment in April 2009, we evaluated several factory-treated clothing exposure scenarios including short-term and long-term cancer risks to adults, youth, and toddlers wearing permethrin-treated clothing. We also evaluated toddler object-to-mouth activity on factory-treated clothing. All scenarios resulted in risk estimates below our level of concern.
• In June 2011, we initiated a new review of all permethrin uses, called registration review, opening docket EPA-HQ-OPP-2011-0039. We expect to complete the registration review of permethrin in 2017.

Treating Your Own Clothing

We also register products that consumers can spray on clothing to repel mosquitoes and ticks. The products that are currently available contain DEET, permethrin or picaridin. Be sure to read and follow label directions if you use one of these products.

For the safe and effective use of pesticide products, always read the product label before using the product.

Ensuring Safety

Remember these important points to use repellents safely:

Applying the Product

• Read and follow the label directions to ensure proper use; be sure you understand how much to apply.
• Apply repellents only to exposed skin and/or clothing. Do not use under clothing.
• Do not apply near eyes and mouth, and apply sparingly around ears.
• When using sprays, do not spray directly into face; spray on hands first and then apply to face.
• Never use repellents over cuts, wounds, or irritated skin.
• Do not spray in enclosed areas.
• Avoid breathing a spray product.
• Do not use it near food.

Other Safety Tips

• Check the label to see if there are warnings about flammability. If so, do not use around open flames or lit cigarettes.
• After returning indoors, wash treated skin and clothes with soap and water.
• Do not use any product on pets or other animals unless the label clearly states it is for animals.
• Most insect repellents do not work against lice or fleas.
• Store insect repellents safely out of the reach of children, in a locked utility cabinet or garden shed.
• Use other preventive actions to avoid getting bitten by:
  • Mosquitoes
  • Ticks

Repellents and Children

We advise consumers to always read and follow label directions in using any pesticide product, including insect repellents.

Because children frequently put their hands in their eyes and mouths, EPA recommends that all repellent products have the following precautionary statements related to children on their labels:

• Do not allow children to handle this product, and do not apply to children's hands. When using on children, apply to your own hands and then put it on the child.
• After returning indoors, wash your child's treated skin and clothes with soap and water or bathe.

According to the product labels, some oil of lemon eucalyptus products should not be used on children under the age of three. There are no restrictions for use on children under three years of age for certain insect repellent products containing oil of lemon eucalyptus as their sole active ingredient at concentrations of 30% or less.

Applicants seeking to amend restrictive language from the labels of their EPA registered OLE products, at the specifications described above, must first submit an application to EPA. In doing so, applicants must consider their source of OLE and acknowledge where data compensations might apply.

Questions often arise about use of DEET on children. DEET is approved for use on children with no age restriction. Also, 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 us to believe there is a need to restrict the use of DEET.

Always store insect repellents safely out of the reach of children.

If you are concerned about using repellent products on children you may wish to consult a health care provider for advice or contact the National Pesticide Information Center (NPIC) or through their toll-free number, 1-800-858-7378.

Maximizing Effectiveness

Apply and re-apply a repellent according to the label instructions. Don't overuse the products, but be sure to apply the amount of repellent indicated by the label. If you don't follow the label directions, the product may not be as effective as you expect. The label on the insect repellent product is your guide to using these products safely and effectively. The effectiveness of the product can vary due to conditions such as:

• Physical activity/perspiration.
• Water exposure.
• Air temperature.
• How attractive you are to mosquitoes and ticks; every person is different.

Look for an EPA registration number (EPA Reg. No.) on the insect repellent product label. This registration number means the company provided EPA with technical information on the effectiveness of the product. The Centers for Disease Control and Prevention (CDC) recommends the use of products registered by EPA.

Using the right insect repellent and other preventive actions can discourage mosquitoes, ticks and other biting insects from landing on you. Here are tips for other preventive actions you can take against mosquitoes.

Remove Mosquito Habitats

• Eliminate standing water in rain gutters, old tires, buckets, plastic covers, toys, or any other container where mosquitoes can breed.
• Empty and change the water in bird baths, fountains, wading pools, rain barrels, and potted plant trays at least once a week to destroy potential mosquito habitats.
• Drain or fill temporary pools of water with dirt.
• Keep swimming pool water treated and circulating.

Use Appropriate Pesticides

• Control mosquito larvae using the appropriate methods for the habitat
• Control adult mosquitoes using insecticides.

Use Structural Barriers

• Cover all gaps in walls, doors, and windows to prevent mosquitoes from entering.
• Make sure window and door screens are in good working order.
• Completely cover baby carriers and beds with netting.

Avoid Getting Bitten

• Keep mosquitoes away from exposed skin by wearing long-sleeved shirts, long pants, and socks.
• Tuck shirts into pants and pants into socks to cover gaps in your clothing where mosquitoes can get to your skin.
• Stay indoors when possible, especially if there is a mosquito-borne disease warning in effect.
• Use EPA-registered mosquito repellents when necessary and follow label directions and precautions closely.
• Use head nets, long sleeves and long pants if you venture into areas with high mosquito populations, such as salt marshes.
• Replace your outdoor lights with yellow "bug" lights, which tend to attract fewer mosquitoes than ordinary lights. The yellow lights are NOT repellents, however.

Using the right insect repellent and other preventive actions can discourage ticks, mosquitoes, and other biting insects from landing on you. Here are tips for other preventive actions you can take against ticks.

Avoid Tick Habitats

• Reduce time spent in potentially tick-infested habitats such as tall grass and shrubs.
• Reduce leaf litter and mow tall grass or brush that may serve as tick habitat.
• Walk in the center of trails to avoid contact with adjacent vegetation.

Avoid Tick Bites

• Keep ticks away from exposed skin by wearing long-sleeved shirts, long pants, and high boots.
• Tuck shirts into pants and pants into socks to cover gaps in your clothing where ticks can get in.
• Wear light-colored clothing to be able to see ticks more easily.
• Check the entire body for ticks; promptly remove attached ticks without squeezing them!