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Permethrin-Treated Clothing: How It Works

Permethrin is an insecticide for clothing and gear, never for skin. At 0.5 percent, treated clothing repels and kills the ticks, chiggers and mosquitoes that touch it. Factory-treated garments are labeled for efficacy through many launderings. One 0.5 percent spray label puts self-treated clothing at six weeks before re-treating.

What is permethrin?

The National Pesticide Information Center describes permethrin as an insecticide in the pyrethroid family, and pyrethroids as synthetic chemicals that act like natural extracts from the chrysanthemum flower. It was first registered with the U.S. Environmental Protection Agency in 1979 and re-registered in 2006, and NPIC counts more than 1,400 registered products containing it.

The EPA is more technical: a broad spectrum, non-systemic, synthetic pyrethroid insecticide that targets adults and larvae of many species of biting, chewing, scaling, soil and flying invertebrates. And when used to pre-treat clothing, it is an insect repellent.

Why does permethrin go on clothing and never on skin?

The CDC says do not use permethrin products directly on skin. The CDC Yellow Book says permethrin should never be applied to the skin but only to clothing, mosquito nets or other fabrics as directed on the product label. The label on file with the EPA for a 0.5 percent clothing treatment (EPA Reg. No. 50404-3) goes further: the product must not be applied to clothing while it is being worn, and under no circumstances should bare skin or clothing on the body be treated.

The reason is not mysterious. NPIC notes that when people get permethrin on their skin they may have irritation or tingling, burning and itching at that spot, and in the eyes it can cause redness, pain or burning. Wearing the treated fabric is a different exposure. NPIC says permethrin applied properly binds tightly to fabrics, with little loss during washing and minimal transfer to skin, and the EPA says the amount allowed in clothing is very low, that human exposure from wearing factory-treated clothing is also low, and that available data show permethrin is poorly absorbed through the skin.

How does treated fabric actually stop a tick or a mosquito?

By contact. NPIC is blunt about it: "Permethrin is not an insect repellent, but kills insects on contact. It is sometimes used to treat fabrics." An insect has to touch the treated item to be harmed or killed. What follows, per NPIC, is an attack on the insect nervous system, causing muscle spasms, paralysis and death. Permethrin is more toxic to insects than to people and dogs, because insects cannot break it down as quickly.

The CDC frames it as both effects at once. Its Yellow Book calls permethrin a highly effective insecticide, an acaricide, meaning a pesticide lethal to ticks and mites, and a repellent, and says that at 0.5 percent, permethrin-treated clothing repels and kills the ticks, chiggers and mosquitoes that meet it, along with other biting and nuisance arthropods.

Contact creates a hard boundary. The EPA states that when you wear permethrin factory-treated clothing, only the skin surface covered by that clothing is protected from the pests listed on the label, and that other exposed parts of the body should be treated with an insect repellent labeled for use on human skin. Treated pants do nothing for your forearms. The 0.5 percent label tells you to pay particular attention to socks, trouser cuffs and shirt cuffs, and to wear pant cuffs inside socks or footwear for full protection against ticks and chiggers.

How long does factory-treated clothing last?

Longer than most people expect. The CDC says permethrin-treated items provide protection after multiple washings, and tells you to read the product label to find out how long. The Yellow Book is more specific: treated materials retain repellency or insecticidal activity after repeated launderings, and clothing treated before purchase is labeled for efficacy through many launderings.

The numbers live on the label. The EPA-accepted hang-tag for Insect Shield Repellent Apparel (EPA Reg. No. 74843-2, permethrin 0.52 percent) carries the line "REPELLENCY REMAINS EFFECTIVE FOR [70][50][25] WASHINGS," with the bracketed figures marked on the label as optional or alternate text, so the number a given garment claims varies. The same label warns that dry cleaning removes the active ingredient.

That tag is the pesticide label. The EPA treats factory-treated clothing as a pesticide product that must carry a pesticide use label, which on clothing is a hang-tag attached to the outside of the garment. Keep it.

How long does clothing you treat yourself last?

Weeks, not years. The CDC's instruction is to use 0.5 percent permethrin on clothing and gear, following the product label. One 0.5 percent label on file with the EPA spells out the timeline: the active ingredient binds to the fabric, providing residual protection that lasts a minimum of six weeks, or 42 days, and holds up through several machine washings, and clothing should be re-treated after six weeks or after the sixth laundering to maintain adequate protection.

The application details are specific. Treat the outer surfaces of each outfit, front and back, for 30 seconds a side, then let it dry at least two hours, or four hours in humid conditions. Do not treat underwear, hats, caps or inner clothing. The Yellow Book adds that items must be treated 24 to 48 hours before packing for travel to allow them to dry.

The label also tells you to keep doing the basics: avoid areas where pests are found, wear light-colored clothing with a long-sleeved shirt and long pants tucked into socks, and inspect your body daily for ticks. How you pull one off matters too.

What do the CDC and EPA say about it?

The CDC's tick prevention page lists it among the steps before going outdoors: treat clothing and gear with products containing 0.5 percent permethrin, which it says can be used on boots, clothing and camping gear and remains protective through several washings, or buy treated clothing and gear instead. Its mosquito prevention page is briefer, telling people to wear clothing and gear treated with permethrin, which it calls an insecticide that kills or repels mosquitoes.

The EPA's position comes out of its registration process. It requires efficacy data for pests of public health concern such as mosquitoes and ticks, and says it reviewed those data for permethrin factory-treated clothing and found it effective in repelling target pests. Its 2009 revised assessment evaluated multiple exposure scenarios, including toddlers wearing or mouthing the clothing and military personnel wearing treated uniforms daily, and reported that all of them showed permethrin factory-treated clothing is unlikely to pose any significant immediate or long-term hazard to people wearing it. Permethrin was first registered for clothing use by the military in 1990, consumer factory-treated products followed in 2003, and it is still the only insect repellent used for factory treatment of clothing.

How is this different from a repellent you put on your skin?

Different job, different surface, different clock. The EPA lists the active ingredients in registered skin-applied insect repellents: DEET, picaridin, IR3535, oil of lemon eucalyptus, p-menthane-3,8-diol, 2-undecanone, catnip oil and oil of citronella. Those products go where fabric does not: face, hands and other exposed areas of the body.

Durability is the sharpest contrast. The Yellow Book notes that clothing treated with other repellent products, such as DEET, protects against biting arthropods but will not last through washing and requires more frequent application. Permethrin bonds to the fabric and survives the laundry.

Neither replaces the other. Wear the treated clothing, cover exposed skin separately: that is the layering behind tick-bite prevention and mosquito-borne illness guidance alike.

What does treated clothing not do?

It does not make you invisible. The EPA-accepted label for factory-treated apparel carries two lines worth reading: that neither the apparel nor any other insect protection product can guarantee complete protection from insects or insect bites, and that it does not protect against diseases or reactions from insect bites. It does not work on everything, either. The Yellow Book states that permethrin-impregnated clothing and insect repellent have not been proven effective against tsetse flies.

And it does not retire the routine. The CDC still wants a tick check after you come indoors, a shower within two hours, which it says has been shown to reduce the risk of getting Lyme disease, and clothes tumble dried on high heat for 10 minutes to kill ticks riding in on dry fabric. Tick exposure can happen year-round, it notes, though ticks are most active April through September.

How should you wash and handle treated clothing?

Wash treated clothing separately. The EPA explains why: small amounts of permethrin can come off in the wash, only outer clothing is treated, and these products are not to be applied to certain clothing such as underwear.

Cats are the household exception. NPIC reports that cats are more sensitive to permethrin than dogs or people because it takes their bodies a long time to break it down, and that cats exposed by accident to products with high, 45 to 65 percent, levels of permethrin may seem anxious, may not walk normally, may have muscle tremors and seizures, and may die.

NPIC also notes that permethrin is highly toxic to fish and other animals that live in water, and to bees and other beneficial insects, and it says to apply these products outdoors in well ventilated areas protected from wind. One more reason to handle standing water around the house instead of spraying more.

Common questions

Can I dilute permethrin and use it on my skin?

No. The CDC says not to use permethrin products directly on skin, and the Yellow Book says it should never be applied to the skin, only to clothing, mosquito nets or other fabrics as directed on the label.

Does permethrin wash out of treated clothing?

Some does. The EPA says small amounts of permethrin can come off in the wash, which is why the label tells you to wash treated clothing separately. Factory-treated garments carry a wash count on the hang-tag. One 0.5 percent label says self-treated clothing should be re-treated after six weeks or after the sixth laundering.

Is this the same permethrin used for head lice and scabies?

Same active ingredient, different regulatory category. NPIC notes that some permethrin products treat scabies and head lice on people, and that those are drugs regulated by the U.S. Food and Drug Administration. Clothing treatments are pesticides regulated by the EPA, with directions for fabric only.

About Longsleeve

Longsleeve is an EPA-registered picaridin lotion (EPA Reg. No. 101457-1). It repels mosquitoes and ticks for up to 14 hours. It is fragrance-free, with nine disclosed ingredients.

None of this is medical advice. If you develop a rash or a fever after a bite, call your doctor and tell them what bit you.

Sources

  1. CDC, About Permethrin-Treated Clothing and Gear. https://www.cdc.gov/mosquitoes/prevention/about-permethrin-treated-clothing-and-gear.html
  2. CDC, Preventing Tick Bites. https://www.cdc.gov/ticks/prevention/index.html
  3. CDC, Preventing Mosquito Bites. https://www.cdc.gov/mosquitoes/prevention/index.html
  4. CDC Yellow Book, Mosquitoes, Ticks, and Other Arthropods. https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html
  5. EPA, Repellent-Treated Clothing. https://www.epa.gov/insect-repellents/repellent-treated-clothing
  6. EPA, Skin-Applied Repellent Ingredients. https://www.epa.gov/insect-repellents/skin-applied-repellent-ingredients
  7. NPIC, Permethrin General Fact Sheet (PDF). https://npic.orst.edu/factsheets/PermGen.pdf
  8. NPIC, Insect Repellents Fact Sheet. https://npic.orst.edu/factsheets/repellents.html
  9. NPIC, Permethrin Treated Clothing. https://npic.orst.edu/pest/mosquito/ptc.html
  10. EPA Pesticide Product Label, Insect Shield Repellent Apparel, EPA Reg. No. 74843-2 (PDF). https://www3.epa.gov/pesticides/chem_search/ppls/074843-00002-20170515.pdf
  11. EPA Pesticide Product Label, CIC Residual Insecticide No. 1, EPA Reg. No. 50404-3 (PDF). https://www3.epa.gov/pesticides/chem_search/ppls/050404-00003-20151006.pdf

Last reviewed 2026-08-06 · every claim on this page is sourced above