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Natural Bug Repellents: What the Evidence Supports

By Andrew Rothaus, Founder ·

Natural is not a regulatory category for bug repellents. The meaningful line separates EPA-registered products, including plant-derived oil of lemon eucalyptus, which are evaluated for effectiveness, from minimum-risk exempt products, whose ingredients EPA reviewed for safety but whose effectiveness was never evaluated. An EPA registration number on the label marks the difference.

Amber glass dropper bottle of essential oil next to fresh eucalyptus branches on a plain surface

What counts as a natural repellent?

There is no natural checkbox on a repellent label. EPA characterizes the active ingredients DEET and picaridin as conventional repellents, while OLE, PMD, IR3535, and 2-undecanone are biopesticide repellents derived from, or synthetic versions of, natural materials. Even biopesticide needs unpacking: the National Pesticide Information Center explains that oil of lemon eucalyptus and IR3535 are based on chemicals that occur in nature but are man-made ingredients, and OLE may appear on labels under its chemical name, p-menthane-3,8-diol, or PMD.

EPA also pushes back on the marketing language. Minimum risk pesticide products are composed of chemicals listed on the product label, and the agency notes that claiming a product is free of chemicals is not based on facts and may be considered false or misleading. So instead of natural versus chemical, the split that actually tells you something is registered versus exempt. Registered means EPA reviewed effectiveness data. Exempt means it did not.

Which plant-derived repellent is EPA registered?

Oil of lemon eucalyptus is the headline plant-derived option. The CDC advises using EPA-registered insect repellents containing DEET, picaridin, IR3535, oil of lemon eucalyptus (OLE), para-menthane-diol (PMD), or 2-undecanone. PMD is the synthesized version of oil of lemon eucalyptus. On EPA's list of registered skin-applied active ingredients, OLE appears in 6 registered products; it contains PMD but is a separately regulated pesticide chemical.

OLE is not alone. Catnip oil is an active ingredient in 4 EPA-registered skin-applied repellent products. 2-undecanone, also called methyl nonyl ketone, is in 1. Oil of citronella appears in 3 registered products alongside its use in unregistered products that meet the exemption requirements. Registration carries weight because EPA-registered repellents have been proven effective in reducing biting by insects such as mosquitoes, as well as other arthropods such as ticks and mites.

One age rule: CDC says not to use products containing OLE or PMD on children under 3 years old. Our guide to mosquito repellent for kids covers age guidance in detail.

Is pure lemon eucalyptus essential oil the same thing?

No. The essential oil in the dropper bottle is not the registered repellent. CDC does not recommend using "pure" oil of lemon eucalyptus, the essential oil that is not formulated, as a repellent, because it has not undergone validated testing for safety and efficacy and is not registered with EPA as an insect repellent. The caution runs wider than one oil: the health risks and efficacy of essential oils have not been as widely studied as common insect repellents.

What does the minimum-risk exemption actually mean?

A natural repellent on the shelf may not be registered at all. Unregistered products are sold under an exemption: EPA has exempted certain minimum risk pesticides from registration under the federal pesticide law because it determined they pose little to no risk to human health or the environment, a provision found in 40 CFR 152.25(f). In the 1990s, EPA evaluated the active ingredients in these unregistered products for safety and determined they posed minimal risk to human health at the percentages found in products on the market. But in EPA's own words, "products made from these ingredients have not been evaluated for effectiveness." Safety was reviewed. Effectiveness was not.

EPA's examples of ingredients used in unregistered exempt repellents include citronella oil, cedar oil, geranium oil, peppermint and peppermint oil, and soybean oil. The exemption also carries a limit: minimum risk labels may not link the pests they claim to control with any specific disease. The claim may only be for the pest as a pest, not as a disease vector.

This gap has EPA's attention. After analyzing public comments, the agency concluded that public health products must be supported by evidence that they are effective against the target pest, and it is considering a proposal to remove personal mosquito and tick repellents from the minimum risk exemption. Once removed, those repellents would need EPA registration before sale in the United States.

What is citronella's actual track record?

Citronella has a long paper trail. Oil of citronella is a naturally occurring insect and animal repellent distilled from two grass varieties; its main components are citronellol, citronellal, and geraniol. It was first registered in the United States in 1948 and currently sits on EPA's list of minimum risk pesticides, so it sits in both camps: 3 EPA-registered products use it, and so do exempt products. It repels pests rather than killing them. It works by masking scents that are attractive to insects, making it difficult for them to locate a target to feed.

Natural does not mean nothing to watch: oil of citronella can be mildly irritating to the skin and eyes and may cause skin allergies for some people with prolonged or frequent exposure. We dig deeper in our post on citronella and plant repellents.

What have studies found about natural repellents?

The honest answer is mixed, and the details matter. In a 2017 laboratory study in the Journal of Insect Science, spray-on repellents containing DEET and PMD had the highest efficacy in repelling Aedes aegypti mosquitoes compared with repellents containing other ingredients. The natural-positive result inside that finding: in the study's attraction assays, products containing 30 percent PMD (oil of lemon eucalyptus) or 98 percent DEET produced equally strong reductions in mosquito attraction. A plant-derived registered active matched 98 percent DEET in that laboratory setup, against that species.

The same study was rougher on gadgets. Of five wearable repellent devices tested, only the one releasing metofluthrin significantly reduced the number of attracted mosquitoes, and a citronella candle had no effect. None of the repellent bracelets tested caused a significant reduction in mosquito attraction; the authors hypothesize the concentrations emitted were too low to have an effect. The authors concluded that many of the products they tested that were marketed as repellents do not reduce mosquito attraction to humans.

A 2020 laboratory study in the Journal of Medical Entomology looked specifically at exempt ingredients and found measurable effects: cinnamon oil, peppermint oil, spearmint oil, lemongrass oil, and garlic oil reduced mosquito attraction to human odor. Of five commercial repellent sprays tested, only one reduced mosquito attraction, for up to 30 minutes in that assay. The shape of the result: several oils showed effects while most finished products did not. And no EPA-registered repellents contain garlic oil, rosemary, lemongrass, thyme, or geraniol oils as active ingredients.

Duration is where botanicals struggled most in a 2002 laboratory study in the New England Journal of Medicine. In that study, a formulation containing 23.8 percent DEET had a mean complete-protection time of 301.5 minutes, a soybean-oil-based repellent protected against mosquito bites for an average of 94.6 minutes, and all other botanical repellents tested provided protection for a mean duration of less than 20 minutes. Repellent-impregnated wristbands offered no protection in that study. The CDC Yellow Book is blunt on gadgets: ingesting vitamin B or garlic and wearing sound-emitting devices or repellent-impregnated wristbands are ineffective. We take apart sound-emitting devices in our ultrasonic repellers post.

How do you read a repellent label?

Look for an EPA registration number (EPA Reg. No.). It means the company provided EPA with technical information on the effectiveness of the product. EPA registration of skin-applied repellent products indicates they have been evaluated and approved for human safety and effectiveness when applied according to label instructions, and per CDC, EPA-registered products are considered safe when used as directed, even for pregnant and breastfeeding women. Repellents without a registration number have not been evaluated by EPA, and EPA cannot advise consumers about their effectiveness. CDC states that the effectiveness of non-EPA registered insect repellents, including some natural repellents, is not known, and the CDC Yellow Book advises travelers to avoid them for that reason. To protect against germs spread by mosquitoes, CDC and EPA recommend using an EPA-registered insect repellent.

Concentration matters too. In general, higher concentrations of active ingredient provide longer protection regardless of which active it is, and products with under 10 percent active ingredient might offer only limited protection. EPA also notes that registration testing follows scientific guidelines and approved study methods, yet protection times vary because of differences in testing conditions.

Where does our own product sit? Not in the natural aisle. Picaridin is one of the two actives EPA characterizes as conventional repellents. 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. Weighing the registered actives against each other? Our picaridin vs DEET comparison lays out the evidence.

FAQ

Can you use natural repellents on babies and kids?

Age rules differ by ingredient. The American Academy of Pediatrics does not recommend insect repellents for children younger than two months. CDC says not to use products containing OLE or PMD on children under 3 years old. Per the CDC Yellow Book, repellents containing DEET, picaridin, IR3535, and 2-undecanone can be used on children without age restriction. Some oil of citronella products should not be used on children less than six months old unless directed by a doctor; that information is listed on the product label. Ask your pediatrician what fits your child.

Is oil of lemon eucalyptus natural?

It is plant-derived but not raw. NPIC explains that oil of lemon eucalyptus is based on chemicals that occur in nature but is a man-made ingredient, and PMD is the synthesized version of OLE. CDC does not recommend the pure, unformulated essential oil as a repellent because it has not undergone validated testing for safety and efficacy and is not registered with EPA.

Do citronella candles keep mosquitoes away?

In a 2017 Journal of Insect Science laboratory study, a citronella candle had no effect on the number of mosquitoes attracted. Oil of citronella itself works by masking scents that are attractive to insects, and it appears in 3 EPA-registered products as well as exempt ones, so the ingredient and the candle format are separate questions.

Why can a repellent be sold if its effectiveness was never tested?

Because of the minimum risk exemption in 40 CFR 152.25(f). EPA evaluated the exempt active ingredients for safety in the 1990s and found minimal risk at marketed percentages, but products made from these ingredients have not been evaluated for effectiveness. EPA is now considering a proposal to remove personal mosquito and tick repellents from the exemption, which would require registration before sale.

Sources

  1. CDC Yellow Book, Mosquitoes, Ticks, and Other Arthropods: https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html
  2. CDC, Preventing Mosquito Bites: https://www.cdc.gov/mosquitoes/prevention/index.html
  3. CDC, Preventing Tick Bites: https://www.cdc.gov/ticks/prevention/index.html
  4. EPA, Skin-Applied Repellent Ingredients: https://www.epa.gov/insect-repellents/skin-applied-repellent-ingredients
  5. EPA, Regulation of Skin-Applied Repellents: https://www.epa.gov/insect-repellents/regulation-skin-applied-repellents
  6. EPA, Minimum Risk Pesticide Definition and Product Confirmation: https://www.epa.gov/minimum-risk-pesticides/minimum-risk-pesticide-definition-and-product-confirmation
  7. EPA, Conditions for Minimum Risk Pesticides: https://www.epa.gov/minimum-risk-pesticides/conditions-minimum-risk-pesticides
  8. EPA, Personal Insect Repellents and Minimum Risk Pesticides: https://www.epa.gov/minimum-risk-pesticides/personal-insect-repellents-and-minimum-risk-pesticides
  9. EPA, Find the Repellent that is Right for You: https://www.epa.gov/insect-repellents/find-repellent-right-you
  10. NPIC, Insect Repellents Fact Sheet: https://npic.orst.edu/factsheets/repellents.html
  11. NPIC, Oil of Citronella General Fact Sheet: https://npic.orst.edu/factsheets/citronellagen.html
  12. Journal of Insect Science, 2017, laboratory study of commercial repellent products and devices: https://pmc.ncbi.nlm.nih.gov/articles/PMC5388317/
  13. New England Journal of Medicine, 2002, laboratory study of repellent protection times: https://pubmed.ncbi.nlm.nih.gov/12097535/
  14. Journal of Medical Entomology, 2020, laboratory study of exempt repellent ingredients: https://pubmed.ncbi.nlm.nih.gov/31612914/

Last reviewed 2026-08-17 · every claim on this page is sourced above