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IR3535 vs Permethrin

The same eleven questions, side by side, each answer in the agency's words. No verdict from us: we sell a product built on one of these actives, so the agencies do the talking.

IR3535ethyl butylacetylaminopropionate
Permethrina synthetic pyrethroid insecticide

Per EPA's tool

IR3535

Registered; 41 products in EPA's tool; 2 to 10 h mosquitoes, 2 to 12 h ticks.

Permethrin

Registered since 1979; CDC says fabric only, never skin; Not in EPA’s tool.

What is it, and where does it come from?

IR3535

NPIC calls IR3535 man-made, based on chemicals that occur in nature; CDC files it with biopesticide repellents.

Source and detail: CDC Yellow Book 2024, NPIC, U.S. EPA

EPA's January 2000 fact sheet describes IR3535, chemical name 3-[N-butyl-N-acetyl]-aminopropionic acid, ethyl ester, as structurally related to beta-alanine, which occurs naturally, and records its registration as an active ingredient in February 1999. NPIC's fact sheet calls it a man-made ingredient based on chemicals that occur in nature, and CDC's Yellow Book files it with the biopesticide repellents.

3-[N-Butyl-N-acetyl]-aminopropionic acid, ethyl ester is structurally related to β-alanine, which occurs naturally. The active ingredient is a liquid at room temperature. OPP Chemical Code: 113509 (CAS # 52304-36-6)

U.S. EPA, 3-[N-Butyl-N-acetyl]-aminopropionic acid, ethyl ester (IR3535) (113509) Fact Sheet, January 2000

IR3535 (chemical name: 3-[N-butyl-N-acetyl]-aminopropionic acid, ethyl ester)

CDC Yellow Book 2024, Mosquitoes, Ticks, and Other Arthropods (Wayback Machine capture)

3-[N-Butyl-N-acetyl]-aminopropionic acid, ethyl ester was registered (licensed for sale) as an active ingredient in February 1999. As of January 2000, there was one end product containing this active ingredient.

U.S. EPA, 3-[N-Butyl-N-acetyl]-aminopropionic acid, ethyl ester (IR3535) (113509) Fact Sheet, January 2000

Oil of lemon eucalyptus and IR3535 are based off of chemicals that occur in nature but are man-made ingredients.

NPIC, Insect Repellents General Fact Sheet

EPA characterizes the active ingredients DEET and picaridin as "conventional" repellents. The biopesticide repellents (OLE, PMD, IR3535, and 2-undecanone) are derived from, or are synthetic versions of, natural materials.

CDC Yellow Book 2024, Mosquitoes, Ticks, and Other Arthropods (Wayback Machine capture)
Permethrin

A synthetic pyrethroid that NPIC says acts like natural chrysanthemum extracts, registered by EPA as an insecticide.

Source and detail: EPA, NPIC

Permethrin is an insecticide in the pyrethroid family; NPIC's permethrin fact sheet says pyrethroids are synthetic chemicals that act like natural extracts from the chrysanthemum flower. EPA's Repellent-Treated Clothing page describes it as a broad spectrum, non-systemic, synthetic pyrethroid insecticide, registered as an insecticide for a variety of settings, and says that when used to pre-treat clothing it is an insect repellent.

Permethrin is an insecticide in the pyrethroid family. Pyrethroids are synthetic chemicals that act like natural extracts from the chrysanthemum flower.

NPIC, Permethrin General Fact Sheet

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.

EPA, Repellent-Treated Clothing

How does EPA treat it?

IR3535

EPA registered IR3535 in February 1999 and now lists it in about 45 skin-applied products.

Source and detail: U.S. EPA

EPA registered IR3535 as an active ingredient in February 1999, and its January 2000 fact sheet says the one product then registered met the effectiveness and safety standards EPA requires of products used against public health pests. EPA's skin-applied ingredients page, updated January 2026, now lists IR3535 in about 45 registered products.

3-[N-Butyl-N-acetyl]-aminopropionic acid, ethyl ester was registered (licensed for sale) as an active ingredient in February 1999. As of January 2000, there was one end product containing this active ingredient.

U.S. EPA, 3-[N-Butyl-N-acetyl]-aminopropionic acid, ethyl ester (IR3535) (113509) Fact Sheet, January 2000

To help protect the public's health, EPA requires registrants of products used against public health pests to demonstrate that the products meet specific standards for effectiveness as well as for safety. The product currently registered with 3-[N-Butyl-N-acetyl]-aminopropionic acid, ethyl ester as the active ingredient has met the applicable standards.

U.S. EPA, 3-[N-Butyl-N-acetyl]-aminopropionic acid, ethyl ester (IR3535) (113509) Fact Sheet, January 2000

IR 3535 -- EPA pesticide regulatory information (3-[N-Butyl-N-acetyl]-aminopropionic acid, ethyl ester) (about 45 products)

U.S. EPA, Skin-Applied Repellent Ingredients, last updated January 23, 2026
Permethrin

Registered since 1979, EPA says; on clothing by the military since 1990, factory-treated consumer clothing since 2003.

Source and detail: EPA

Registered since 1979, per EPA's Repellent-Treated Clothing page, which says permethrin was first registered in 1990 as a repellent on clothing by the military and that factory-treated consumer clothing was first registered in 2003. EPA's sentence is "The only insect repellent currently used for factory treatment of clothing is permethrin."

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.

EPA, Repellent-Treated Clothing

The only insect repellent currently used for factory treatment of clothing is permethrin.

EPA, Repellent-Treated Clothing

What strengths are registered, and does strength change protection?

IR3535

Labels declare 20 and 19.7 percent; CDC says higher concentrations generally protect longer.

Source and detail: CDC Yellow Book 2024, Carroll JF, U.S. EPA accepted label

Two accepted labels declare the active at 20 percent (EPA Reg. No. 54287-20) and 19.7 percent (EPA Reg. No. 806-32). In a 2010 Journal of Medical Entomology tick trial, the 10 percent IR3535 lotion was significantly less effective than formulations with higher concentrations of repellent, and CDC's Yellow Book says higher concentrations of active ingredient generally provide longer protection, regardless of the active.

ACTIVE INGREDIENT: 3-((N-butyl-N-acetyl)-amino propionic acid ethyl ester*..............................................................20% OTHER INGREDIENTS:............................................................80%

U.S. EPA accepted label, Super Guard 3535 Insect Repellent, EPA Reg. No. 54287-20, December 17, 2015

ACTIVE INGREDIENT: 3-[N-butyl-N-acetyl]-aminopropionic acid, ethyl ester* 19.7% OTHER INGREDIENTS: 80.3% TOTAL: 100.0%

U.S. EPA accepted label, Avon Skin-So-Soft SSS Bug Guard Plus IR3535 Expedition Insect Repellent SPF 30, EPA Reg. No. 806-32, January 23, 2018

The 10% IR3535 lotion was significantly less effective than the formulations with higher concentrations of repellent. In the formulations tested, deet, picaridin, and IR3535 provided lasting protection against A. americanum.

Carroll JF, Benante JP, Kramer M, Lohmeyer KH, Lawrence K. Formulations of deet, picaridin, and IR3535 applied to skin repel nymphs of the lone star tick (Acari: Ixodidae) for 12 hours. J Med Entomol. 2010 Jul;47(4):699-704. PMID 20695288

In general, higher concentrations of active ingredients provide longer duration of protection, regardless of the active ingredient.

CDC Yellow Book 2024, Mosquitoes, Ticks, and Other Arthropods (Wayback Machine capture)
Permethrin

Permethrin at 0.5% on clothing repels and kills ticks, chiggers and mosquitoes, CDC says; labels list 0.50%.

Source and detail: CDC Yellow Book, EPA stamped label

CDC's Yellow Book says that at a concentration of 0.5 percent, permethrin-treated clothing repels and kills ticks, chiggers, mosquitoes and other biting and nuisance arthropods. The accepted label for a permethrin clothing treatment, EPA Reg. No. 50404-3, gives its active ingredient as permethrin 0.50 percent, and the accepted hang-tag label for factory-treated apparel, EPA Reg. No. 74843-2, gives permethrin at 0.52 percent.

At a concentration of 0.5%, permethrin-treated clothing repels and kills ticks, chiggers, mosquitoes, and other biting and nuisance arthropods.

CDC Yellow Book, Mosquitoes, Ticks, and Other Arthropods (Wayback Machine capture 2026-09-19)

ACTIVE INGREDIENT: Permethrin*……..……. 0.50%

EPA stamped label, CIC Residual Insecticide No. 1, EPA Reg. No. 50404-3, accepted October 6, 2015

Permethrin 0.52%

EPA stamped label, Insect Shield Repellent Apparel, EPA Reg. No. 74843-2, dated May 15, 2017

How long does EPA say it protects?

IR3535

One label says reapply after 12 hours for deer ticks, 8 for mosquitoes and 6 for gnats.

Source and detail: U.S. EPA, U.S. EPA accepted label

The accepted label for Avon Skin-So-Soft Bug Guard Plus IR3535 Expedition (EPA Reg. No. 806-32, 19.7 percent) says reapply after 12 hours for deer ticks, 8 hours for mosquitoes and 6 hours for gnats, no-see-ums, sand flies and biting midges. EPA's search tool, whose database EPA says was last updated in June 2019, lists Superguard 3535 (EPA Reg. No. 54287-20, 20 percent) at 8 hours for mosquitoes, with no tick registration.

FOR PROTECTION from deer ticks reapply after 12 hours, and for mosquitoes reapply after 8 hours, and for gnats, no-seeums, sand flies and biting midges reapply after 6 hours.

U.S. EPA accepted label, Avon Skin-So-Soft SSS Bug Guard Plus IR3535 Expedition Insect Repellent SPF 30, EPA Reg. No. 806-32, January 23, 2018

| Superguard 3535 Insect Repellent (SPF 20) | 8 | X | IR3535 | 20 | Associated Registrations | 54287-20

U.S. EPA, Insect Repellents: Use and Effectiveness search results for IR3535

Product Name Hourly Protection Time for Mosquitoes Hourly Protection Time for Ticks Active Ingredient(AI) AI% in Product Formula Company Name EPA Registration Number

U.S. EPA, Insect Repellents: Use and Effectiveness search results for 2-undecanone

An asterisk ( * ) indicates that EPA has technical information on the effectiveness of the product against mosquitoes and/or ticks and the company chose not to have a specific time associated with their product. * An " X " indicates that the repellent product has not been registered for protection from ticks.

U.S. EPA, Insect Repellents: Use and Effectiveness search results

Any products listed are for informational purposes only. Inclusion of a product listed/referenced is not an endorsement. * EPA and the U.S. Government do not endorse any product or service. * The information in this database was last updated in June 2019.

U.S. EPA, Find the Repellent that is Right for You

ACTIVE INGREDIENT: 3-[N-butyl-N-acetyl]-aminopropionic acid, ethyl ester* 19.7% OTHER INGREDIENTS: 80.3% TOTAL: 100.0%

U.S. EPA accepted label, Avon Skin-So-Soft SSS Bug Guard Plus IR3535 Expedition Insect Repellent SPF 30, EPA Reg. No. 806-32, January 23, 2018
Permethrin

Labels say six weeks or six washes when you treat clothing, 70, 50 or 25 washings when factory-treated.

Source and detail: CDC Yellow Book, EPA stamped label

The accepted label for a 0.5 percent permethrin clothing treatment, EPA Reg. No. 50404-3, says protection lasts a minimum of six weeks, with retreatment after six weeks or the sixth laundering; the hang-tag for factory-treated apparel, EPA Reg. No. 74843-2, says repellency remains effective for a bracketed 70, 50 or 25 washings. CDC's Yellow Book says treated materials retain repellency after repeated launderings but should be retreated per the label.

This product contains an active ingredient, which actually binds to the fabric being treated, providing residual protection, which lasts a minimum of six weeks [42 days], and holds up through several machine washings. Follow standard laundering procedures. Clothing should be retreated after six weeks [42 days] or after the sixth laundering to maintain adequate protection.

EPA stamped label, CIC Residual Insecticide No. 1, EPA Reg. No. 50404-3, accepted October 6, 2015

REPELLENCY REMAINS EFFECTIVE FOR [70][50][25] WASHINGS

EPA stamped label, Insect Shield Repellent Apparel, EPA Reg. No. 74843-2, dated May 15, 2017

Permethrin-treated materials retain repellency or insecticidal activity after repeated launderings but should be retreated as described on the product label to provide continued protection. Clothing treated before purchase is labeled for efficacy through many launderings.

CDC Yellow Book, Mosquitoes, Ticks, and Other Arthropods (Wayback Machine capture 2026-09-19)

ACTIVE INGREDIENT: Permethrin*……..……. 0.50%

EPA stamped label, CIC Residual Insecticide No. 1, EPA Reg. No. 50404-3, accepted October 6, 2015

Which pests do accepted labels name, and what does CDC say those pests carry?

IR3535

EPA lists mosquitoes, deer ticks, body lice and biting flies; a label adds gnats, no-see-ums and sand flies.

Source and detail: CDC, U.S. EPA, U.S. EPA accepted label

EPA's 2000 fact sheet lists IR3535's target pests as mosquitoes, deer ticks, body lice and biting flies; the accepted label for EPA Reg. No. 806-32 claims repellency against deer ticks, mosquitoes, gnats, no-see-ums, sand flies and biting midges. CDC says some U.S. ticks carry pathogens that can cause Lyme disease and Powassan virus, and that mosquitoes can spread pathogens through bites, naming West Nile virus, dengue and malaria.

o Use Sites: Human skin. o Target Pests: Mosquitoes, deer ticks, body lice, and biting flies.

U.S. EPA, 3-[N-Butyl-N-acetyl]-aminopropionic acid, ethyl ester (IR3535) (113509) Fact Sheet, January 2000

Strong [repellency] [protection] against deer ticks, mosquitoes, gnats, no-seeums, sand flies and biting midges

U.S. EPA accepted label, Avon Skin-So-Soft SSS Bug Guard Plus IR3535 Expedition Insect Repellent SPF 30, EPA Reg. No. 806-32, January 23, 2018

In the United States, some ticks carry pathogens that can cause human disease, including: * Alpha-gal syndrome * Anaplasmosis * Babesiosis * Bourbon virus * Colorado tick fever * Ehrlichiosis * Hard tick relapsing fever * Heartland virus * Lyme disease * Powassan virus * Rickettsia parkeri rickettsiosis * Rocky Mountain spotted fever * Soft tick relapsing fever * STARI * Tularemia

CDC, About Ticks and Tickborne Disease (Wayback Machine capture of cdc.gov/ticks/about/index.html)

Almost everyone has been bitten by a mosquito. Mosquitoes can spread pathogens (germs) through bites. A person who gets bitten by a mosquito and gets sick has a mosquito-borne disease like West Nile virus, dengue, or malaria.

CDC, About Mosquitoes (Wayback Machine capture of cdc.gov/mosquitoes/about/index.html)
Permethrin

Labels name mosquitoes, ticks, chiggers, mites, ants, flies and midges.

Source and detail: EPA stamped label

The accepted label for a 0.5 percent permethrin clothing treatment, EPA Reg. No. 50404-3, says it repels and kills mosquitoes, chiggers, mites and ticks, in the label's words "including Ticks which carry Lyme Disease and Rocky Mountain Spotted Fever." The accepted hang-tag label for factory-treated apparel, EPA Reg. No. 74843-2, claims that it repels mosquitoes, ticks, ants, flies, chiggers and midges.

To repel & kill mosquitoes, chiggers, mites and ticks, including Ticks which carry Lyme Disease and Rocky Mountain Spotted Fever.

EPA stamped label, CIC Residual Insecticide No. 1, EPA Reg. No. 50404-3, accepted October 6, 2015

REPELS MOSQUITOES, TICKS, ANTS, FLIES, CHIGGERS, AND MIDGES

EPA stamped label, Insect Shield Repellent Apparel, EPA Reg. No. 74843-2, dated May 15, 2017

ACTIVE INGREDIENT: Permethrin*……..……. 0.50%

EPA stamped label, CIC Residual Insecticide No. 1, EPA Reg. No. 50404-3, accepted October 6, 2015

What do the agencies say about children?

IR3535

CDC says no age restriction; one label says ask a doctor under 6 months, adult applies under 10.

Source and detail: CDC Yellow Book 2024, U.S. EPA accepted label

CDC's Yellow Book says repellents containing IR3535 can be used on children without age restriction. The accepted labels carry their own cautions: EPA Reg. No. 806-32 says ask a doctor for children under 6 months and that an adult must apply it to children under age 10, and EPA Reg. No. 54287-20 says use on children under 6 months only with the advice of a physician.

Insect repellents containing DEET, picaridin, IR3535, and 2-undecanone can be used on children without age restriction (see EPA webpage on Using Insect Repellents Safely and Effectively with Children ).

CDC Yellow Book 2024, Mosquitoes, Ticks, and Other Arthropods (Wayback Machine capture)

An adult must apply this product to children under age 10. Children under 6 months: Ask a doctor. Do not apply over wounds, freshly shaved or irritated skin.

U.S. EPA accepted label, Avon Skin-So-Soft SSS Bug Guard Plus IR3535 Expedition Insect Repellent SPF 30, EPA Reg. No. 806-32, January 23, 2018

CAUTION: For external use only. Causes moderate eye irritation. Do not get in eyes. Use on children under 6 months of age only with the advice of a physician.

U.S. EPA accepted label, Super Guard 3535 Insect Repellent, EPA Reg. No. 54287-20, December 17, 2015
Permethrin

No minimum age stated; EPA's 2009 review called treated clothing unlikely to pose significant hazard, toddlers included.

Source and detail: EPA

No CDC, EPA or label source we read states a minimum age for wearing permethrin-treated clothing. The closest agency statement is EPA's: its 2009 revised exposure and risk assessment evaluated multiple exposure scenarios for permethrin factory-treated clothing, including toddlers wearing or mouthing the clothing, and all scenarios showed the clothing is unlikely to pose any significant immediate or long-term hazard to people wearing it.

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.

EPA, Repellent-Treated Clothing

What do CDC and WHO say about pregnancy?

IR3535

CDC says EPA recommends no precautions for pregnant or lactating women beyond its usual repellent tips.

Source and detail: CDC Yellow Book 2024, NPIC, World Health Organization

CDC's Yellow Book says EPA recommends no precautions beyond its usual tips for using registered repellents on women who are pregnant or lactating, and NPIC reports that CDC recommends an EPA-registered repellent with DEET, picaridin, IR3535 or oil of lemon eucalyptus for pregnant mothers in areas with Zika risk. WHO's malaria and dengue fact sheets name IR3535 among the repellents they list, and neither fact sheet we read ties a repellent choice to pregnancy.

Other than the safety tips listed above, EPA does not recommend any additional precautions for using registered repellents on children or on women who are pregnant or lactating.

CDC Yellow Book 2024, Mosquitoes, Ticks, and Other Arthropods (Wayback Machine capture)

CDC also recommends the use of an EPA-registered repellent with DEET, picaridin, IR3535, or oil of lemon eucalyptus for pregnant mothers in areas with risk of Zika. 28 Consult a healthcare professional for more information.

NPIC, Insect Repellents General Fact Sheet

Use mosquito repellents (containing DEET, IR3535 or Icaridin) after dusk.

World Health Organization, Malaria fact sheet

To lower your risk of getting dengue, protect yourself from mosquito bites by using: * clothes that cover as much of your body as possible; * mosquito nets, ideally sprayed with insect repellent, if sleeping during the day; * window screens; * mosquito repellents (containing DEET, Picaridin or IR3535); and * coils and vaporizers.

World Health Organization, Dengue and severe dengue fact sheet
Permethrin

EPA says no evidence of reproductive or developmental effects to mother or child; no CDC statement found.

Source and detail: EPA

EPA's Repellent-Treated Clothing page says that, based on its review of scientific studies, there is no evidence of reproductive or developmental effects to mother or child following exposure to permethrin. No CDC or WHO page we read makes a permethrin-specific pregnancy statement.

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

EPA, Repellent-Treated Clothing

What do NPIC and EPA report about absorption and toxicity?

IR3535

NPIC rates oral, inhalation and dermal toxicity very low, eye irritation moderate; undiluted IR3535 can irritate skin.

Source and detail: NPIC, U.S. EPA

EPA's 2000 fact sheet says toxicity tests show IR3535 is not harmful when ingested, inhaled or used on skin. NPIC's fact sheet rates it very low for oral, inhalation and dermal toxicity and moderate for eye irritation; NPIC adds that undiluted IR3535 can cause skin irritation, that skin irritation was not reported in studies with diluted IR3535, and that feeding studies show concentrated IR3535 is low in developmental and reproductive toxicity.

IR3535 has been used as an insect repellent in Europe for 20 years with no substantial adverse effects. Toxicity tests show that the IR3535 is not harmful when ingested, inhaled, or used on skin.

U.S. EPA, 3-[N-Butyl-N-acetyl]-aminopropionic acid, ethyl ester (IR3535) (113509) Fact Sheet, January 2000

| IR3535 13 | Very Low | Very low | Very Low | Moderate | Very low

NPIC, Insect Repellents General Fact Sheet, Table 1. Short-Term Toxicity of Active Ingredients in Common Insect Repellents

IR3535 : IR3535 is an eye irritant. Human and animal studies show if it is undiluted, it can cause skin irritation. In studies with diluted IR3535, skin irritation was not reported. 18,19

NPIC, Insect Repellents General Fact Sheet

IR3535 : Multiple feeding studies show concentrated IR3535 is low in developmental and reproductive toxicity. 19,22

NPIC, Insect Repellents General Fact Sheet
Permethrin

EPA says treated clothing gives low exposure and skin absorbs it poorly; NPIC says it may irritate skin.

Source and detail: EPA, NPIC

EPA's Repellent-Treated Clothing page says the amount of permethrin allowed in clothing is very low, that human exposure from wearing permethrin factory-treated clothing is low, and that available data show permethrin is poorly absorbed through the skin. NPIC says people who get permethrin on their skin may have irritation or tingling, burning and itching at that spot, and in the eyes it can cause redness, pain or burning.

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.

EPA, Repellent-Treated Clothing

When people get permethrin on their skin, they may have irritation or tingling, burning and itching at that spot. If permethrin gets in the eyes it can cause redness, pain or burning.

NPIC, Permethrin General Fact Sheet

Does it damage plastics, fabrics or gear?

IR3535

Labels say keep it off plastics; one adds costume jewelry, leather, synthetic fibers and painted surfaces.

Source and detail: U.S. EPA accepted label

Two accepted labels say to keep it off plastics. EPA Reg. No. 806-32 says avoid contact with plastics, costume jewelry, leather and synthetic fibers, and that it may damage painted or varnished surfaces, including nail polish; EPA Reg. No. 54287-20 says the product contains alcohol and to avoid contact with plastics.

Avoid contact with plastics, costume jewelry, leather and synthetic fibers. May damage painted or varnished surfaces, including nail polish.

U.S. EPA accepted label, Avon Skin-So-Soft SSS Bug Guard Plus IR3535 Expedition Insect Repellent SPF 30, EPA Reg. No. 806-32, January 23, 2018

PHYSICAL OR CHEMICAL HAZARDS: Flammable. Keep away from heat and open flame. Contains alcohol. Avoid contact with plastics.

U.S. EPA accepted label, Super Guard 3535 Insect Repellent, EPA Reg. No. 54287-20, December 17, 2015
Permethrin

CDC says never on skin, only clothing, nets and fabrics; a label adds tents, sleeping bags and backpacks.

Source and detail: CDC Yellow Book, EPA stamped label

CDC's Yellow Book says permethrin should never be applied to skin, only to clothing, nets or other fabrics as the label directs. The label for a 0.5 percent permethrin treatment, EPA Reg. No. 50404-3, lists netting, tents, sleeping bags, backpacks, hammocks and camping chairs, with no treating inside a sleeping bag and only the exterior surfaces of a tent sprayed; the hang-tag for factory-treated apparel, EPA Reg. No. 74843-2, says dry cleaning removes the active ingredient.

Permethrin should never be applied to the skin but only to clothing, mosquito nets, or other fabrics as directed on the product label.

CDC Yellow Book, Mosquitoes, Ticks, and Other Arthropods (Wayback Machine capture 2026-09-19)

GEAR: MOSQUITO NETTING, NETS, TENTS, CANOPIES, SCREEN ENCLOSURES, SLEEPING BAGS, BACKPACKS, GROUNDCLOTHS, HAMMOCKS AND CAMPING CHAIRS: Do not treat inside of sleeping bag. Spray exterior surfaces of tent only.

EPA stamped label, CIC Residual Insecticide No. 1, EPA Reg. No. 50404-3, accepted October 6, 2015

DRYCLEANING REMOVES ACTIVE INGREDIENT- DO NOT DRY CLEAN

EPA stamped label, Insect Shield Repellent Apparel, EPA Reg. No. 74843-2, dated May 15, 2017

ACTIVE INGREDIENT: Permethrin*……..……. 0.50%

EPA stamped label, CIC Residual Insecticide No. 1, EPA Reg. No. 50404-3, accepted October 6, 2015

What do the agencies say about pets?

IR3535

Only EPA's general rule applies: nothing on pets unless the label says so.

Source and detail: U.S. EPA

No IR3535 label we read mentions pets or other animals. The rule that applies is EPA's general one: do not use any repellent product on pets or other animals unless the label clearly states it is for animals.

Do not use any product on pets or other animals unless the label clearly states it is for animals.

U.S. EPA, Using Insect Repellents Safely and Effectively
Permethrin

NPIC says cats are more sensitive than dogs or people because they break it down slowly.

Source and detail: NPIC

NPIC says permethrin is more toxic to insects than to people and dogs, and that cats are more sensitive than dogs or people because their bodies take a long time to break it down. NPIC's technical fact sheet describes a report of 11 cats intentionally treated with products containing 45 to 65 percent permethrin: all 11 were hospitalized, with muscle tremors, seizures, incoordination and agitation, and four died.

Permethrin is more toxic to insects than it is to people and dogs. This is because insects can't break it down as quickly as people and dogs. Cats are more sensitive to permethrin than dogs or people because it takes their bodies a long time to break it down.

NPIC, Permethrin General Fact Sheet

A report of 11 cats intentionally treated with products containing 45-65% permethrin described adverse effects including muscle tremors, seizures, incoordination and agitation after exposure. Of the 11 cats that were treated, all were hospitalized, and four died after the exposure.

NPIC, Permethrin Technical Fact Sheet (archived)

Which studies are on the record?

IR3535

A 2008 controlled-release trial: 7.1 to 10.3 hours against field mosquitoes, 9.1 to 12.2 against lab ticks.

Source and detail: Carroll JF, Carroll JF. Prolonged efficacy of IR3535 repellents against mosquitoes and blacklegged ticks in North America. J Med Entomol. 2008 Jul;45(4):706-14. PMID 18714871

Carroll et al., Journal of Medical Entomology 2010: formulations of 20 percent or more, IR3535 among them, let fewer than 10 percent of lone star ticks cross treated bands over 12 hours; the 10 percent IR3535 lotion was significantly less effective. Carroll, same journal, 2008, tested controlled-release IR3535 formulations at 10 and 20 percent: complete protection times of 7.1 to 10.3 hours against mosquitoes in the field and 9.1 to 12.2 hours against blacklegged ticks in the laboratory.

Formulations containing > or = 20% active ingredient were highly effective, with <10% of the ticks crossing through the treatment bands for any challenge during the 12 h. At least 40% of ticks exposed to any formulation for any challenge fell or crawled off the volunteers. There was no difference in effectiveness between the 20% spray and 20% lotion formulations of picaridin.

Carroll JF, Benante JP, Kramer M, Lohmeyer KH, Lawrence K. Formulations of deet, picaridin, and IR3535 applied to skin repel nymphs of the lone star tick (Acari: Ixodidae) for 12 hours. J Med Entomol. 2010 Jul;47(4):699-704. PMID 20695288

The 10% IR3535 lotion was significantly less effective than the formulations with higher concentrations of repellent. In the formulations tested, deet, picaridin, and IR3535 provided lasting protection against A. americanum.

Carroll JF, Benante JP, Kramer M, Lohmeyer KH, Lawrence K. Formulations of deet, picaridin, and IR3535 applied to skin repel nymphs of the lone star tick (Acari: Ixodidae) for 12 hours. J Med Entomol. 2010 Jul;47(4):699-704. PMID 20695288

Complete protection times ranged from 7.1 to 10.3 h for mosquitoes and from 9.1 to 12.2 h for blacklegged ticks. Long protection duration resulted in many cases being truncated by darkness or eventual subject withdrawal, which suggests that actual protection times were probably greater.

Carroll JF. Prolonged efficacy of IR3535 repellents against mosquitoes and blacklegged ticks in North America. J Med Entomol. 2008 Jul;45(4):706-14. PMID 18714871

I tested novel, controlled-release formulations of IR3535, at 10% in lotion and at 20% in pump spray and aerosol, against mosquitoes in the field and blacklegged ticks in the laboratory.

Carroll JF. Prolonged efficacy of IR3535 repellents against mosquitoes and blacklegged ticks in North America. J Med Entomol. 2008 Jul;45(4):706-14. PMID 18714871
Permethrin

One trial found 3.36 times fewer tick bites on subjects wearing permethrin-treated outfits than untreated ones.

Source and detail: Miller NJ

Miller 2011 (Journal of Medical Entomology) found that subjects wearing outfits treated with permethrin received 3.36 times fewer tick bites than subjects wearing untreated outfits, with no statistically significant difference between commercial permethrin treatment and the do-at-home application method. In the same study, 97.6 percent of nymphs attached to subjects in untreated outfits were alive, against 22.6 percent on subjects in repellent-treated outfits.

Subjects wearing outfits treated with permethrin received 3.36 times fewer tick bites than subjects wearing untreated outfits. No statistically significant differences in number of tick bites were detected between commercial permethrin treatment (19.33%) and the do-at-home permethrin application method (24.67%).

Miller NJ, Rainone EE, Dyer MC, Gonzalez ML, Mather TN. Tick bite protection with permethrin-treated summer-weight clothing. J Med Entomol. 2011 Mar;48(2):327-33. PMID 21485369

On subjects wearing untreated outfits, 97.6% of attached nymphs were alive, whereas significantly fewer (22.6%) attached nymphs were alive on subjects wearing repellent-treated outfits.

Miller NJ, et al. J Med Entomol. 2011 Mar;48(2):327-33. PMID 21485369

Sources on this page.

23 sources. Every quote was fetched on or before 2026-09-22 and is stored with the page. Last reviewed 2026-09-22. All ten actives.

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