Insect Repellents: How to Choose
What are the best insect repellents to protect you from biting bugs such as mosquitoes, ticks, flies, gnats, chiggers, midges, fleas and no-see-ums?
This article offers you details about DEET vs. picaridin vs. plant-derived repellents, but we summarize our basic advice first.
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Insect Repellents: Basic Advice
- Apply insect repellent to exposed skin following label instructions. They reflect the conditions under which each product has been tested and often identify which insects the product targets.
- Which repellent to use? For longest protection, synthesized active ingredients such as DEET and picaridin can last 4 to 10+ hours; see product labels for time estimates. If you prefer to keep it natural, you’ll need to reapply often. Repellents using essential plant oils are believed to be effective for 30 minutes to 2+ hours.
- Apply permethrin to clothing, or wear clothing pretreated with the compound such as Insect Shield® apparel. Permethrin kills ticks that linger on treated fabric, and it deters mosquitoes from biting through clothing. Tip: Applying insect repellent under clothing is ineffective; don’t waste your time.
- Around a campsite or backyard patio, use insect-repelling candles, diffusers, mosquito coils and mosquito sticks. These devices are most effective in windless conditions.
- For serious swarms, wear a headnet. Add netted coverings (bug jacket, bug pants) as needed.
Note: Insect repellents are not effective against stinging insects (bees, wasps, hornets).
Active Ingredient Options
|Picaridin||Chemical||Yes||Up to 8 hours|
|Oil of lemon
|Yes||Up to 6 hours|
|Plant oils (soybean,
|No||Estimated 30 min.
to 2 hours
Synthesized Plant Oils
Background: Developed in Germany by Merck in early 1980s; registered in U.S. in 1999. Chemical name: 3-[N-Butyl-N-acetyl]-aminopropionic acid, ethyl ester. Derived from the amino acid alanine.
Effectiveness: Potential duration of effectiveness: Up to 8 hours. Refer to product label.
Safety: From the EPA: “IR3535 has been used as an insect repellent in Europe for 20 years with no substantial adverse effects. Toxicity tests show that IR3535 is not harmful when ingested, inhaled, or used on skin.” The American Academy of Pediatrics has made no recommendation on the use of IR3535.
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Natural (Nonsynthesized) Plant Oils
Permethrin: Repellent for Clothing
Insect Repellents and Kids
- The American Academy of Pediatrics advises using no repellent on infants younger than 2 months.
- If using DEET, choose concentrations of no greater than 30%.
- Any repellent may cause skin irritation for children with sensitive skin. If this occurs, try a different formula.
- Kids find sprays more fun to apply, but lotions are typically milder on their skin.
Registered vs. Unregistered Repellents
Active ingredients are what make insect repellents effective. Repellents are considered pesticides, and before most can be marketed they must be registered with the EPA.
However, 30+ active ingredients made from plant oils are exempted from EPA registration. That means they are safe for humans but not necessarily effective.
Unregistered: The EPA has a list of 31 “minimum-risk pesticides”—plant-based ingredients (both active and inert) that the agency describes as “demonstrably safe for the intended use.” Data demonstrating effectiveness, though, is not required for these ingredients. Thus repellents in this group could bill themselves as “EPA approved; all-natural.” Yet their duration of effectiveness is uncertain—believed to be between 30 minutes and 2+ hours—well short of what synthetics deliver.
Examples: Essential plant oils (lemongrass oil, cedar oil, geranium oil and many others) or food ingredients (corn oil, cloves and clove oil).
What diseases are transmitted by insects, and which insects do the transmitting? Here are links to information provided by the CDC and FDA.
Malaria. To protect international travelers from aggressive mosquitoes that carry this disease, the CDC advises the use of repellent, treated clothing and bed-netting and preventative pre-travel medication.
Zika virus. Like with malaria, the CDC recommends using repellent, treated clothing and bed-netting to prevent mosquito bites when traveling in areas where Zika virus is found.
Other mosquito-transmitted diseases include yellow fever (a vaccine is available and may be required for entry into some countries), dengue fever, Japanese encephalitis and chikungunya fever. For current news of specific locations, visit the CDC’s travel site.
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Mosquito photo courtesy of Cristi Day, REI Asheville, N.C., sales lead.
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