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Skin-applied active

2-Undecanone

methyl nonyl ketone

2-Undecanone is a biopesticide repellent originally derived from wild tomato plants; EPA lists one registered skin product.

Source and detail: CDC Yellow Book 2024, U.S. EPA, Witting-Bissinger BE

2-Undecanone, chemical name methyl nonyl ketone, is the active in a repellent that a 2008 Journal of Medical Entomology paper describes as originally derived from wild tomato plants and registered by EPA in 2007 at 7.75 percent. CDC's Yellow Book files it with the biopesticide repellents, derived from or synthetic versions of natural materials. The thing to get right is its size: EPA's ingredients page lists it in exactly one registered skin-applied product, and the EPA chemical fact sheet on methyl nonyl ketone we found, from 1995, covers its use as a dog and cat repellent.

2-undecanone (chemical name: methyl nonyl ketone)

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

In 2007, a new repellent, BioUD, with the active ingredient 7.75% 2-undecanone, originally derived from wild tomato (Lycopersicon hirsutum Dunal f. glabratum C. H. Müll) plants, was registered by the U.S. Environmental Protection Agency.

Witting-Bissinger BE, Stumpf CF, Donohue KV, Apperson CS, Roe RM. Novel arthropod repellent, BioUD, is an efficacious alternative to deet. J Med Entomol. 2008 Sep;45(5):891-8. PMID 18826032

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)

2-undecanone -- EPA pesticide regulatory information (or methyl nonyl ketone) (1 product)

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

Methyl nonyl ketone is a dog and cat repellent/training aid and iris borer deterrent. The pesticide is used in households, paths, patios, solid waste containers and on ornamental plants.

U.S. EPA, R.E.D. FACTS Methyl Nonyl Ketone, EPA-738-F-95-033, July 1995
EPA statusRegistered; 1 product in EPA's tool
Protection, per EPA's tool5 h mosquitoes, 2 h ticks
Youngest ageNo age limit (CDC)
GearThe label carries no plastics or materials warning; no agency statement found.
PetsOnly EPA's general rule applies: nothing on pets unless the label says so.

Product counts and hours are what EPA's repellent search tool listed on 2026-08-18; the other three lines are the agencies' words, sourced below.

Eleven questions.

One line each. Open any source for the full text and the exact quote.

What is it, and where does it come from?

2-Undecanone is methyl nonyl ketone; one 2008 paper says it was originally derived from wild tomato plants.

Source and detail: CDC Yellow Book 2024, U.S. EPA, Witting-Bissinger BE

2-Undecanone is methyl nonyl ketone; CDC's Yellow Book files it with the biopesticide repellents, derived from or synthetic versions of natural materials. A 2008 Journal of Medical Entomology paper says the 7.75 percent 2-undecanone in the repellent EPA registered in 2007 was originally derived from wild tomato plants. EPA's 1995 reregistration fact sheet describes methyl nonyl ketone as a dog and cat repellent, training aid and iris borer deterrent.

2-undecanone (chemical name: methyl nonyl ketone)

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

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)

In 2007, a new repellent, BioUD, with the active ingredient 7.75% 2-undecanone, originally derived from wild tomato (Lycopersicon hirsutum Dunal f. glabratum C. H. Müll) plants, was registered by the U.S. Environmental Protection Agency.

Witting-Bissinger BE, Stumpf CF, Donohue KV, Apperson CS, Roe RM. Novel arthropod repellent, BioUD, is an efficacious alternative to deet. J Med Entomol. 2008 Sep;45(5):891-8. PMID 18826032

Methyl nonyl ketone is a dog and cat repellent/training aid and iris borer deterrent. The pesticide is used in households, paths, patios, solid waste containers and on ornamental plants.

U.S. EPA, R.E.D. FACTS Methyl Nonyl Ketone, EPA-738-F-95-033, July 1995

How does EPA treat it?

EPA lists 2-undecanone in one registered skin-applied product; no EPA skin-repellent fact sheet found.

Source and detail: U.S. EPA

EPA's skin-applied ingredients page, updated January 2026, lists 2-undecanone, or methyl nonyl ketone, as the active ingredient in one registered product. We found no EPA fact sheet for it as a skin repellent; the EPA chemical document we did find, the July 1995 R.E.D. Facts for methyl nonyl ketone, was written for its use as a dog and cat repellent, training aid and iris borer deterrent.

2-undecanone -- EPA pesticide regulatory information (or methyl nonyl ketone) (1 product)

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

Methyl nonyl ketone is a dog and cat repellent/training aid and iris borer deterrent. The pesticide is used in households, paths, patios, solid waste containers and on ornamental plants.

U.S. EPA, R.E.D. FACTS Methyl Nonyl Ketone, EPA-738-F-95-033, July 1995

What strengths are registered, and does strength change protection?

One label declares 7.75 percent; CDC says higher concentrations generally protect longer, regardless of the active.

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

One strength is on the record: the accepted label for Bio-UD-8 Spray (EPA Reg. No. 82669-2) declares 2-undecanone at 7.75 percent, and EPA's ingredients page lists the active in one registered product. On strength in general, CDC's Yellow Book says that in general higher concentrations of active ingredient provide longer protection regardless of the active, and NPIC says higher concentration repellents may protect longer but are not better at keeping insects away.

ACTIVE INGREDIENT 2-Undecanone [CAS# 112-12-9] ..... . 7.75% OTHER INGREDIENTS ............................. .. 92.25%

U.S. EPA accepted label, Bio-UD-8 Spray, EPA Reg. No. 82669-2, January 8, 2009

2-undecanone -- EPA pesticide regulatory information (or methyl nonyl ketone) (1 product)

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

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)

Higher concentration repellents may protect people for longer. However, they are not better at keeping insects away. 5,6,7 Repellents with less than 10% of an active ingredient may only offer protection for short periods of time (1-2 hours). 5

NPIC, Insect Repellents General Fact Sheet

How long does EPA say it protects?

EPA's tool lists 5 hours for mosquitoes, 2 for ticks; the label says up to 4.5 and 2.

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

EPA's repellent search tool, whose database EPA says was last updated in June 2019, lists Bio-UD-8 Spray (EPA Reg. No. 82669-2, 7.75 percent) at 5 hours for mosquitoes and 2 hours for ticks. The product's 2009 accepted label says it repels mosquitoes for up to 4.5 hours and ticks that may transmit Lyme disease for up to 2 hours, and says for best results to spray skin every 4.5 hours.

| BIO-UD-8 Spray | 5 | 2 | 2-undecanone | 7.75 | HOMS LLC | 82669-2

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

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

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

Repels mosquitoes for up to 4.5 hours Repels mosquitoes that may carry West Nile Virus for

U.S. EPA accepted label, Bio-UD-8 Spray, EPA Reg. No. 82669-2, January 8, 2009

Repels ticks that may transmit Lyme Disease for up to 2 hours

U.S. EPA accepted label, Bio-UD-8 Spray, EPA Reg. No. 82669-2, January 8, 2009

Shake well before using. This bottle is. designed to spray upside down. For best results spray skin every 4.5 hours.

U.S. EPA accepted label, Bio-UD-8 Spray, EPA Reg. No. 82669-2, January 8, 2009

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

The label names mosquitoes, ticks and other arthropods.

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

The accepted label for Bio-UD-8 Spray (EPA Reg. No. 82669-2) says it repels ticks and other arthropods, mosquitoes that may transmit West Nile virus, and ticks that may transmit Lyme disease. CDC says mosquitoes can spread pathogens through bites, naming West Nile virus, dengue and malaria, and counts Lyme disease among the diseases caused by pathogens some U.S. ticks carry.

Repels ticks and other arthropods

U.S. EPA accepted label, Bio-UD-8 Spray, EPA Reg. No. 82669-2, January 8, 2009

Protection for up to 4.5 hours from Repels ticks and other arthropods mosquitoes that may transmit West Nile Virus

U.S. EPA accepted label, Bio-UD-8 Spray, EPA Reg. No. 82669-2, January 8, 2009

Repels ticks that may transmit Lyme Disease for up to 2 hours

U.S. EPA accepted label, Bio-UD-8 Spray, EPA Reg. No. 82669-2, January 8, 2009

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)

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)

What do the agencies say about children?

CDC says no age restriction; the label says an adult should apply it to children under 10.

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

CDC's Yellow Book says repellents containing 2-undecanone can be used on children without age restriction, and NPIC's fact sheet says that if no age limit appears on a label, EPA has not put age restrictions on the product. The accepted label for EPA Reg. No. 82669-2 says an adult should apply it to children under 10 years of age and that children should not apply it.

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)

Check the product label to see if there is a minimum age for use. If no age limit is on the label, the EPA has not put age restrictions on the product.

NPIC, Insect Repellents General Fact Sheet

An adult should apply this product to children under 10 years of age. Do not allow children to apply this product

U.S. EPA accepted label, Bio-UD-8 Spray, EPA Reg. No. 82669-2, January 8, 2009

What do CDC and WHO say about pregnancy?

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

Source and detail: CDC, CDC Yellow Book 2024, U.S. EPA, World Health Organization

CDC's tick prevention page lists 2-undecanone among EPA-registered repellent actives, and CDC's Yellow Book says EPA recommends no precautions beyond its usual tips for registered repellents on women who are pregnant or lactating. The WHO malaria and dengue fact sheets we read do not name 2-undecanone. EPA's 1995 methyl nonyl ketone findings report no evidence of maternal toxicity, developmental toxicity or mutagenicity.

Use Environmental Protection Agency (EPA)-registered insect repellents containing DEET, picaridin, IR3535, Oil of Lemon Eucalyptus (OLE), para-menthane-diol (PMD), or 2-undecanone. 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.

CDC, Preventing Tick Bites (Wayback Machine capture of cdc.gov/ticks/prevention/index.html)

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)

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

No evidence of maternal toxicity, developmental toxicity, or mutagenicity is associated with methyl nonyl ketone. Based on available information, no toxicological endpoints of concern (including short term or intermediate term) were identified.

U.S. EPA, R.E.D. FACTS Methyl Nonyl Ketone, EPA-738-F-95-033, July 1995

What do NPIC and EPA report about absorption and toxicity?

EPA's 1995 review of the dog and cat repellent found no oral or inhalation toxicity in animals.

Source and detail: U.S. EPA

EPA's 1995 reregistration of methyl nonyl ketone, the dog and cat repellent, found no toxicity by the oral and inhalation routes in laboratory animals, Toxicity Category IV, the lowest of four, and slight toxicity, Category III, for dermal toxicity, eye irritation and dermal irritation, plus weak dermal sensitization. We found no EPA or NPIC toxicity review of the 7.75 percent skin product.

In studies using laboratory animals, methyl nonyl ketone exhibited no toxicity via the oral and inhalation routes and was placed in Toxicity Category IV (the lowest of four categories) for these effects.

U.S. EPA, R.E.D. FACTS Methyl Nonyl Ketone, EPA-738-F-95-033, July 1995

Methyl nonyl ketone was slightly toxic (Toxicity Category III) for dermal toxicity, eye irritation and dermal irritation and was a weak dermal sensitizer.

U.S. EPA, R.E.D. FACTS Methyl Nonyl Ketone, EPA-738-F-95-033, July 1995

Methyl nonyl ketone is a dog and cat repellent/training aid and iris borer deterrent. The pesticide is used in households, paths, patios, solid waste containers and on ornamental plants.

U.S. EPA, R.E.D. FACTS Methyl Nonyl Ketone, EPA-738-F-95-033, July 1995

Does it damage plastics, fabrics or gear?

The label carries no plastics or materials warning; no agency statement found.

Source and detail: U.S. EPA accepted label

The accepted label for Bio-UD-8 Spray (EPA Reg. No. 82669-2) that we read carries no plastics or materials warning. Its one line on gear is an optional claim that the product can be applied on skin and clothing, and no agency page we read says whether 2-undecanone damages plastics.

Optional Label Claims: - Can be applied on skin & clothing

U.S. EPA accepted label, Bio-UD-8 Spray, EPA Reg. No. 82669-2, January 8, 2009

What do the agencies say about pets?

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

Source and detail: U.S. EPA

EPA's rule for every skin repellent applies: no product on pets or other animals unless the label clearly states it is for animals. We found nothing about animals on the skin label for EPA Reg. No. 82669-2; EPA's separate 1995 reregistration of methyl nonyl ketone as a dog and cat repellent requires the label line that persons and pets must not enter a treated area until sprays have dried.

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

"Do not allow persons or pets to enter the treated area until sprays have dried."

U.S. EPA, R.E.D. FACTS Methyl Nonyl Ketone, EPA-738-F-95-033, July 1995

Methyl nonyl ketone is a dog and cat repellent/training aid and iris borer deterrent. The pesticide is used in households, paths, patios, solid waste containers and on ornamental plants.

U.S. EPA, R.E.D. FACTS Methyl Nonyl Ketone, EPA-738-F-95-033, July 1995

Which studies are on the record?

One 2008 trial reported repellency against American dog ticks for at least 2.5 hours on skin.

Source and detail: Witting-Bissinger BE

Witting-Bissinger et al., Journal of Medical Entomology 2008, reported no difference in mean repellency over 6 hours between 7.75 percent 2-undecanone and 7 or 15 percent DEET against Aedes albopictus; against Aedes aegypti no difference was found against 7 percent DEET and mean repellency was lower than 15 percent DEET over the same period. The same paper reported repellency against American dog ticks for at least 2.5 hours on skin.

No differences were found in mean repellency over 6 h after application between BioUD versus 7 and 15% deet for Ae albopictus. For Ae. aegypti, no differences were found over the same time period for 7% deet. Compared with 15% deet, BioUD mean repellency was lower over the 6-h test period.

Witting-Bissinger BE, Stumpf CF, Donohue KV, Apperson CS, Roe RM. Novel arthropod repellent, BioUD, is an efficacious alternative to deet. J Med Entomol. 2008 Sep;45(5):891-8. PMID 18826032

Laboratory trials were conducted to determine the repellent activity of BioUD against the American dog tick, Dermacentor variabilis (Say), on human skin and cloth. BioUD repelled ticks at least 2.5 h after application to human skin.

Witting-Bissinger BE, Stumpf CF, Donohue KV, Apperson CS, Roe RM. Novel arthropod repellent, BioUD, is an efficacious alternative to deet. J Med Entomol. 2008 Sep;45(5):891-8. PMID 18826032

In 2007, a new repellent, BioUD, with the active ingredient 7.75% 2-undecanone, originally derived from wild tomato (Lycopersicon hirsutum Dunal f. glabratum C. H. Müll) plants, was registered by the U.S. Environmental Protection Agency.

Witting-Bissinger BE, Stumpf CF, Donohue KV, Apperson CS, Roe RM. Novel arthropod repellent, BioUD, is an efficacious alternative to deet. J Med Entomol. 2008 Sep;45(5):891-8. PMID 18826032

Put it beside another.

2-Undecanone vs DEET2-Undecanone vs Picaridin2-Undecanone vs Permethrin

All ten actives 631 products by ingredient

Sources on this page.

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

  1. CDC Yellow Book 2024, Mosquitoes, Ticks, and Other Arthropods (Wayback Machine capture). https://wwwnc.cdc.gov/travel/yellowbook/2024/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods
  2. Witting-Bissinger BE, Stumpf CF, Donohue KV, Apperson CS, Roe RM. Novel arthropod repellent, BioUD, is an efficacious alternative to deet. J Med Entomol. 2008 Sep;45(5):891-8. PMID 18826032. https://pubmed.ncbi.nlm.nih.gov/18826032/
  3. U.S. EPA, Skin-Applied Repellent Ingredients, last updated January 23, 2026. https://www.epa.gov/insect-repellents/skin-applied-repellent-ingredients
  4. U.S. EPA, R.E.D. FACTS Methyl Nonyl Ketone, EPA-738-F-95-033, July 1995. https://www3.epa.gov/pesticides/chem_search/reg_actions/reregistration/fs_PC-044102_1-Jul-95.pdf
  5. U.S. EPA accepted label, Bio-UD-8 Spray, EPA Reg. No. 82669-2, January 8, 2009. https://www3.epa.gov/pesticides/chem_search/ppls/082669-00002-20090108.pdf
  6. NPIC, Insect Repellents General Fact Sheet. https://npic.orst.edu/factsheets/repellents.html
  7. U.S. EPA, Insect Repellents: Use and Effectiveness search results for 2-undecanone. https://cfpub.epa.gov/oppref/insect_s/search_results.cfm?Rangetime=&hidSelected=1&ProductName=&Ingredient=2-undecanone&Company=null&Registration=
  8. U.S. EPA, Find the Repellent that is Right for You. https://www.epa.gov/insect-repellents/find-repellent-right-you
  9. CDC, About Mosquitoes (Wayback Machine capture of cdc.gov/mosquitoes/about/index.html). https://www.cdc.gov/mosquitoes/about/index.html
  10. CDC, About Ticks and Tickborne Disease (Wayback Machine capture of cdc.gov/ticks/about/index.html). https://www.cdc.gov/ticks/about/index.html
  11. CDC, Preventing Tick Bites (Wayback Machine capture of cdc.gov/ticks/prevention/index.html). https://www.cdc.gov/ticks/prevention/index.html
  12. World Health Organization, Malaria fact sheet. https://www.who.int/news-room/fact-sheets/detail/malaria
  13. World Health Organization, Dengue and severe dengue fact sheet. https://www.who.int/news-room/fact-sheets/detail/dengue-and-severe-dengue
  14. U.S. EPA, Using Insect Repellents Safely and Effectively. https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively