Active Ingredients found in Insect Repellents

Updated: July 5, 2007

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EPA fact sheet: How to Use Insect Repellents Safely

Insect repellents are products that people use on skin, clothing, or in our immediate surroundings, to repel or keep away annoying insects. This fact sheet will help you understand the active ingredients commonly used in insect repellents. More information about using insect repellents safely.

Before you use any insect repellent, be sure you read the label for any warnings and also to see what the active ingredients are. The substances in insect repellents that actually repel the insects are the active ingredients, and are registered with EPA. Also, insect repellents are approved for all ages unless the label specifically states an age limitation or precaution that you need to be aware of. As long as you read and follow label directions and take proper precautions, EPA-registered insect repellents do not present health or safety concerns.

An EPA Registration number on the product label means the product has been evaluated by EPA to ensure that it will not pose unreasonable adverse effects on humans, the environment, and non-target species. A pesticide can be legally used only if it has been registered (or licensed) with EPA. An EPA Registration Number typically contains two unique numbers, a company number followed by a dash and then a product number. Sometimes registration numbers may contain a third unique number which is the distributor number.

*Note: EPA registered insect repellents are not recommended to repel lice. Also, human insect repellent products should not be used on your pets. Only use products labeled for pet use on your dog, cat, or other domestic pet. Read the label first: Protect your pets.

Combination Sunscreen and Insect Repellent Products

Products that combine sunscreen and insect repellent are registered by EPA as pesticides. As with any other pesticide, be sure you use these products according to the label directions and heed the precautions to be sure you are safe.

Active Ingredients in Insect Repellents

Conventional Repellents

DEET (chemical name, N,N-diethyl-meta-toluamide or N,N-diethly-3-methyl-benzamide) is the active ingredient found in many insect repellent products. It is used to repel biting pests such as mosquitoes and ticks, including ticks that may carry Lyme disease. 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 percent DEET. Additional information on DEET.
Picaridin (chemical name, 2-(2-hydroxyethyl)-1-piperidinecarboxylic acid 1-methylpropyl ester) is a colorless, nearly odorless liquid active ingredient that is used as an insect repellant against biting flies, mosquitoes, chiggers, and ticks. Picaridin products were sold in Europe and Australia for several years before being introduced to the U.S. market in 2005. Products contain a range of 5 to 20 percent of the active ingredient. Technical fact sheet on Picaridin (PDF) (6 pp, 83K, About PDF.)

Biopesticide Repellents

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What are biopesticides?

Oil of Lemon Eucalyptus Is an extract from the leaves and twigs of Eucalyptus cittriodora also known as Corymbia citriodora. The pesticide products using oil of lemon eucalyptus were registered in 2000 to repel mosquitoes and deer ticks. There are several products now registered both as lotion and spray formulations. As with most plant oils, no adverse effects to humans are expected from the use of oil of lemon eucalyptus products when label directions are followed. Products contain a range of 30 to 40 active ingredient. Technical fact sheet on Oil of Lemon Eucalyptus (PDF) (4 pp, 44K, About PDF.)
p-Mentane-3,8-diol is the chemically synthesized version of oil of lemon eucalyptus. It is applied to skin or to clothing to repel specific insects including mosquitoes, biting flies, and gnats. According to the Centers for Disease Control and Prevention, when repellents containing p-Mentane-3,8-diol were tested against mosquitoes found in the U.S., the p-Mentane-3,8-diol products provided protection similar to repellants with low concentrations of DEET. Products contain a range of 8 to 10 percent of the active ingredient. Technical fact sheet on p-Mentane-3,8-diol.
Methyl nonyl ketone was originally registered in 1966 as a dog and cat repellent/training aid and an iris borer deterrent. Methyl nonyl ketone is currently found in only one insect repellent in the form of both a lotion and a spray. Technical fact sheet on Methyl nonyl ketone (PDF) (5 pp, 35K, About PDF.)
IR3535 (chemical name, 3-[N-Butyl-N-acetyl]-aminopropionic acid, ethyl ester), also called Merck 3535, is used as an insect repellent against mosquitoes, deer ticks, and biting flies. This biopesticide was registered as an active ingredient in 1999. Before it was registered with EPA, IR3535 had been used as an insect repellent in Europe for 20 years with no significant harmful effects. Products contain a range of 7.5 to 20.07 percent of the active ingredient. Technical fact sheet on IR3535.
Oil of Citronella comes from dried, cultivated grasses, and has a distinctive odor that masks the CO2 or lactic acid on our bodies that mosquitoes and other pests find attractive. It has been used for over 50 years as an insect repellent. However, oil of citronella is included on the list of chemicals that may not require EPA registration in some cases. Unless a product containing citronella is EPA-registered, it has not been subject to EPA review and EPA cannot corroborate its safety and effectiveness. Oil of citronella products are commonly sold as repellent candles but only skin applied products offer some protection in certain circumstances. Most skin-applied products contain about 5 percent oil of citronella. Technical fact sheet on Oil of Citronella.

Area Repellents and Repellents Used on Clothing

Permethrin is registered for use as both an insecticide and a repellent. Permethrin products are used on clothing, shoes, bed nets, and camping gear. Permethrin-impregnated clothing such as pre-treated shoes, socks, and pants repel and kill ticks, mosquitoes, and other insects and retain this effect after repeated laundering. Permethrin is also found in treated tents, tarps, bed nets, sleeping bags, and mattresses. Fact sheet on Permethrin.
Allethrin is an outdoor area-wide repellent that is used for the control of mosquitoes. Heating causes allethrin to vaporize from mosquito coils, mats, and oil formulations. It is also used frequently in commercially available tabletop candles and lanterns. See Docket EPA-HQ-OPP-2006-0986 for information about Alletherin at Regulations.gov.
Metofluthrin is also an outdoor area-wide repellent that is used for the control of mosquitoes. This recently EPA-registered active ingredient is currently found in strip devices. Metofluthrin "strip devices" are multilayer paper or plastic devices that you hang up as an area repellent. No heating is necessary to vaporize the metofluthrin after the strips are removed from the packaging. Technical toxicology summary on Metofluthrin.

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