DEET vs IR3535

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.

EPA, DEET (epa.gov/insect-repellents/deet), fetched 2026-09-22

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.

EPA, DEET (epa.gov/insect-repellents/deet), fetched 2026-09-22

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)

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.

EPA, DEET (epa.gov/insect-repellents/deet), fetched 2026-09-22

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.

EPA, DEET (epa.gov/insect-repellents/deet), fetched 2026-09-22

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).

EPA, DEET (epa.gov/insect-repellents/deet), fetched 2026-09-22

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

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.

EPA, DEET (epa.gov/insect-repellents/deet), fetched 2026-09-22

In general, higher concentrations of active ingredients provide longer duration of protection, regardless of the active ingredient. Products with <10% active ingredient might offer only limited protection, often 1-2 hours. Products that offer sustained-release or controlled-release (microencapsulated) formulations, even with lower active ingredient concentrations, might provide longer protection times. Studies suggest that DEET efficacy tends to peak at a concentration of approximately 50% and that concentrations above that do not offer a marked increase in protection time against mosquitoes.

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

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)

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.

EPA, DEET (epa.gov/insect-repellents/deet), fetched 2026-09-22

Ben's 100 Insect Repellent | 10 | 10 | DEET | 98.11 | Tender Corp. | 56575-7

EPA, Find the Repellent that is Right for You, search results for DEET, cfpub.epa.gov/oppref/insect_s

While this technical information is based on scientific testing guidelines and approved study methods, there are variations in the resulting protection times because of differences in the testing conditions.

EPA, Find the Repellent that is Right for You

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

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

EFFECTIVE PROTECTION from Mosquitoes, Gnats, No-See-Ums, Biting Flies, Ticks (including ticks that may cause Lyme disease), Chiggers and Fleas

EPA notification label, OFF! Insect Repellent II, EPA Reg. No. 4822-380, 15% DEET aerosol, November 13, 2009

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)

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.

EPA, DEET (epa.gov/insect-repellents/deet), fetched 2026-09-22

Insect repellents containing DEET, picaridin, IR3535, and 2-undecanone can be used on children without age restriction

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

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

Use EPA-registered insect repellents with one of the following active ingredients. When used as directed, EPA-registered insect repellents are proven safe and effective, even for pregnant and breastfeeding women.

CDC, Preventing Mosquito Bites (Wayback Machine capture 2026-09-16)

When used as directed, EPA-registered insect repellents are proven safe and effective, even for pregnant and breastfeeding women. DEET Picaridin (known as KBR 3023 and icaridin outside the United States)

CDC, Preventing Mosquito Bites (Wayback Machine capture 2026-09-16)

The safety of daily application of N, N-diethyl-m-toluamide (DEET) (1.7 g of DEET/day) in the second and third trimesters of pregnancy was assessed as part of a double-blind, randomized, therapeutic trial of insect repellents for the prevention of malaria in pregnancy (n = 897). No adverse neurologic, gastrointestinal, or dermatologic effects were observed for women who applied a median total dose of 214.2 g of DEET per pregnancy (range = 0-345.1 g).

McGready R, et al. Safety of the insect repellent N,N-diethyl-M-toluamide (DEET) in pregnancy. Am J Trop Med Hyg. 2001 Oct;65(4):285-9. PMID 11693870

DEET crossed the placenta and was detected in 8% (95% confidence interval = 2.6-18.2) of cord blood samples from a randomly selected subgroup of DEET users (n = 50). No adverse effects on survival, growth, or development at birth, or at one year, were found. This is the first study to document the safety of DEET applied regularly in the second and third trimesters of pregnancy.

McGready R, et al. Am J Trop Med Hyg. 2001 Oct;65(4):285-9. PMID 11693870

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

When DEET was applied to the skin of volunteers by researchers, they found that a small amount of the DEET was taken into the body through the skin. When DEET and alcohol are applied to the skin, more DEET is taken into the skin compared with DEET alone. Drinking alcohol may also cause more DEET to be absorbed through the skin. Sunscreen products that contain DEET may cause more DEET to be taken into the body through the skin.

NPIC, DEET General Fact Sheet

DEET generally is of low acute toxicity, and, based on the available toxicological data, the Agency believes that the normal use of DEET does not present a health concern to the general U.S. population (the Agency's human risk assessment has identified no toxicologically significant effects in animal studies.) DEET has been classified as a Group D carcinogen (not classifiable as a human carcinogen.)

EPA, R.E.D. FACTS: DEET, EPA-738-F-95-010, April 1998

In summary, since 1960, there have been 14 cases of seizure, including four deaths, potentially related to DEET exposure, for which other more likely causes have not been identified. An additional 32 cases of seizure reported to the national DEET registry are currently under review.

EPA, Reregistration Eligibility Decision (RED) DEET, EPA738-R-98-010, approved April 13, 1998

people using DEET each year, the observed incidence of recognized seizures is about one per 100 million users.

EPA, Reregistration Eligibility Decision (RED) DEET, EPA738-R-98-010, approved April 13, 1998

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

DEET is a plasticizer and can damage certain rubber, plastic, vinyl, or elastic materials such as contact lenses, eyeglass frames and lenses, watch crystals, combs, painted and varnished surfaces, and certain synthetic or treated fabrics.

NPIC, DEET Technical Fact Sheet (archived)

Will not damage nylon, cotton, or wool.

EPA amended reregistration label, Cutter Insect Repellent #10GE, EPA Reg. No. 121-53, 10% DEET, March 18, 2009

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

N,N-diethyl-meta-toluamide (DEET) is an insect repellent used in households/domestic dwellings, on the human body and clothing being worn, on cats, dogs, horses and pet living/sleeping quarters. There are no food uses.

EPA, R.E.D. FACTS: DEET, EPA-738-F-95-010, April 1998

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

EPA, Using Insect Repellents Safely and Effectively

Reports of pets being exposed to DEET in amounts that would make them sick are rare. Pets that have been overexposed to DEET have shown varying effects, including vomiting, shaking, excitement, lack of coordination, and seizures.

NPIC, DEET General Fact Sheet

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

Based on a total of 4996 mosquitoes collected on negative control persons, the overall five hour protection rate was 97.4% [95%CI: 97.1-97.8%], not decreasing over time. Picaridin 20% performed equally well as DEET 20% and better than picaridin 10%.

Van Roey K, et al. Field evaluation of picaridin repellents reveals differences in repellent sensitivity between Southeast Asian vectors of malaria and arboviruses. PLoS Negl Trop Dis. 2014 Dec 18;8(12):e3326. PMID 25522134

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.

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

There was no difference in effectiveness between the 20% spray and 20% lotion formulations of picaridin. 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, et al. J Med Entomol. 2010 Jul;47(4):699-704. PMID 20695288

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