Insect Repellents: Safe and Effective Use
The search for an insect repellent can be confusing and sometimes even scary. Is DEET safe? Can I use an insect repellent on my children? What are the most common side effects with insect repellents? These questions, and more, deserve sound answers before you head out into the wild of mother nature.
Not only do insect repellents keep mosquitoes, ticks, biting flies, gnats and other bugs away, insect repellents are a safe and effective way to prevent insect-borne diseases. Several million people worldwide die from mosquito-borne diseases every year, but mosquitoes and other insects can be controlled.
Common Insect-Borne Diseases
Mosquito bites can lead to:
- West Nile virus
- Dengue fever
- Chikungunya virus
- Yellow Fever (rare in US)
- Zika virus
Ticks can cause:
- Lyme disease
- Rocky Mountain Spotted Fever (RMSF)
- Powassan virus (increasing incidence)
The U.S. Centers for Disease Control and Prevention (CDC) recommend the use of insect repellents to prevent mosquito-borne diseases. Insect repellents are also useful to prevent bites, skin eruptions and rashes that may be caused by an insect's bite. Mosquito bites can cause severe skin irritation through an allergic reaction to the mosquito's saliva.
The application of repellents to fight off mosquitos is one of their most common uses. In the 20th century, malaria was eliminated in the temperate area of the world with the use of DDT and other organophosphate insecticides.
However, still today, roughly half of the world's population in tropical or subtropical regions may be exposed to malaria through mosquito bites. Over 229 million cases of malaria occurred in 2019, with most of them in Africa. Over 400,00 deaths were estimated annually. Deaths due to malaria occur mostly in children under 5 years of age in Sub-Saharan Africa.
Insects and arachnids that bite in self-defense instead of to feed -- such as yellow jackets, bees, wasps, hornets, certain ants or spiders -- cannot be repelled with insect repellents.
How Do Insect Repellents Work?
Humans attract mosquitoes and other blood feeding insects by their breath and skin odors. The insect is attracted to the carbon dioxide in a human's breath.
Repellents are effective only at the skin area and close to the treated surface, so mosquitoes may still be seen flying nearby. Repellents contain an ingredient that makes the person unattractive for biting; however, repellents do not kill the insect. Repellents with higher concentrations (percentages) of active ingredient usually provide longer-lasting protection.
Insect Repellent Ingredients
The most effective insect repellents include DEET, Picardin, BioUD, Oil of Lemon Eucalyptus and IR3535. These active ingredients are found in EPA-registered skin-applied insect repellents. For all insect repellent products, follow the instructions listed on the bottle or label.
EPA characterizes the active ingredients in DEET and picaridin as conventional insect repellents. OLE, PMD, IR3535, and 2-undecanone are considered biopesticide repellents as they are derived from, or are synthetic versions of, natural materials.
DEET (Brands: Off, Cutter, Ultrathon, Sawyer)
Studies have shown DEET (N, N-diethyl-m-toluamide) is very effective against insects such as mosquitoes, ticks, chiggers, fleas, and some flies. DEET is a synthetic chemical compound originally developed in the 1950's for military use. DEET can protect you 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.
DEET is available in concentrations ranging from 5 to 100 percent, but concentrations above 30% have not been shown to be more effective. DEET is considered the 'gold standard' of insect repellents.
- DEET is available in lotions, sprays, and wipes for skin application. Long-acting formulations gives roughly 6 to 12 hours of protection and contain roughly 30% DEET.
- DEET can damage synthetic fibers, certain plastics, and watch crystals.
- Allergic reactions and serious side effects are rare. However, rash, mild irritation, urticaria (itching), and skin eruptions have been reported.
The CDC states that DEET is safe for children and infants older than 2 months, and the American Academy of Pediatrics (AAP) suggests that DEET solutions no greater than 30% in concentration be used in children. In children, avoid prolonged, excessive use or internal consumption; encephalopathy has occurred in these situations.
Picaridin (Cutter, Natrapel)
Picaridin (KBR 3023) is available in 5% to 20% concentrations and is an effective repellent for flies, mosquitoes, chiggers, ticks.
- Picaridin is a synthetic chemical that mimics the natural compound piperine found in black pepper. Spray products with at least 20% picaridin have worked as well or better than some deet-based ones.
- An advantage of picaridin over DEET is that it does not damage plastic or fabric and may be less sticky to use on skin than DEET.
- The various brand names are available in spray and wipes for application to the skin.
DEET and Picaridin insect repellents have demonstrated a higher degree of effectiveness in peer-reviewed, scientific literature. Products containing these active ingredients typically provide longer-lasting protection than others.
IR3535 (Avon Skin So Soft Bug Guard Plus, Bull Frog Mosquito Coast)
IR3535 is available in concentrations from 7.5 to 20 percent, and is sold in combination with a sunscreen.
- The CDC does not recommend using combination repellent and sunscreen products because the sunscreen will need to be applied more often than the repellent, and excessive use of the repellent may lead to side effects. It's best to apply each product separately; first the sunscreen then the insect repellent. Follow the reapplication and safe use instructions for each product.
- Some studies have questioned the effectiveness of the lower 7.5% concentration of the IR3535 product.
- IR3535 is available as a lotion and a spray.
Oil of Lemon Eucalyptus (Repel Lemon Eucalyptus, Cutter Lemon Eucalyptus, Coleman Botanicals)
Oil of Lemon Eucalyptus (OLE) (p-menthane 3,8-diol [PMD]) is a plant-based repellent. In studies evaluating malaria, OLE provides 6 hours worth of protection against mosquito bites, but should NOT be used in children less than 3 years of age.
- OLE is registered with the EPA, and is available as a spray. It can cause eye irritation so use caution.
- According to the CDC, when OLE was compared to DEET for mosquitoes found in the U.S., OLE provided similar protection to lower concentrations of DEET.
- OLE is often marketed as a “natural” insect repellent. It is not an "essential oil".
Permethrin (Sawyer Premium Permethrin Clothing Insect Repellent)
Permethrin is available as a spray for clothes, insect nets, sleeping bags, shoes, and boots. It is NOT intended for direct application to the skin.
- Permethrin is a synthetic pyrethroid contact insecticide for gear and clothing only used to repel and kill ticks, chiggers, mosquitoes, and other biting and nuisance arthropods.
- Clothing and other items must be treated 24 to 48 hours in advance of travel to allow them to dry.
- It remains active for several weeks, even after laundering, but retreat clothing and gear as directed on label.
- Clothing that is pre-treated with permethrin before purchase remains active through 70 launderings.
- BioUD (2-undecanone 7.75%) is a synthetic pesticide, registered with the EPA but assigned a low toxicity rating. It is derived from wild tomato plants (Lycopersicon hirsutum Dunal f. glabratum C. H. Müll).
- In studies, when BioUD was compared to DEET 7% to 30%, against the mosquitoes Aedes aegypti (L.) and Aedes albopictus Skuse, overall, BioUD was found to be an effective repellent for mosquitoes (up to 6 hours) and ticks (up to 2.5 hours).
Catnip oil (Nepeta cataria, also known as catmint)
The ingredient is extract of Oil Nepeta cataria which is a member of the mint family of plants (Labiatae). Catnip is a herb that grows year-round and grows wild in most parts of the United States. It is registered with the EPA.
- It is used as an active ingredient for direct application to human skin to repel black flies, mosquitoes and other biting insects.
- Reapplication after six hours will be necessary. Researchers have reported that catnip oil is about 10 times more effective than DEET.
- The EPA concludes that no risks to human health are expected due to low toxicity and current use as a food ingredient by the general public without any reported adverse effects on human health. However, it can can lead to eye irritation.
Oil of Citronella
Oil of citronella is distilled from two grass varieties. It can be formulated into sprays, lotions, wristbands, and sunscreen products, among others such as candles. Oil of citronella is EPA registered and products made from this ingredient have not been evaluated for effectiveness.
- Oil of citronella repels insects rather than killing them.
- Can cause irritation to the skin and eyes, skin allergies, cough or throat irritation.
- Some oil of citronella products should not be used on children less than 6 months old unless directed by a doctor.
Which Bug Spray is Best? EPA Tool for Bug Repellents
The EPA publishes a tool to help consumers determine the best possible choices for skin-applied insect repellents. The tool allows you to specify:
- if you need protection mosquitoes, ticks or both
- length of protection time
- preferred active ingredient
- and other product-specific information.
How to Apply Bug Spray
Judicious use of insect repellents is important. Apply them when you plan to be outside and only to exposed areas of the skin. Do not spray or apply repellent under clothing.
- Use only enough repellent to cover but not saturate the skin.
- It is best to spray repellent into your hands, then rub carefully around the face, eyes and the mouth. Wash your hands after application.
- Choose a repellent that provides protection for the amount of time that you will be outdoors. Frequent reapplication is usually not needed.
- To apply to the face, spray a small amount in the hands, rub hands together, and apply lightly on the face and neck area.
- When applying insect repellents to children, avoid applying to their hands, around their eyes, or to any skin areas that are cut or irritated.
- Spray aerosols outside and away from food.
- Apply sunscreen first, then insect repellent. Use separate products as sunscreen needs to be applied more often.
- Wash the treated skin area with soap and water when you have returned indoors.
- Do not apply repellent to open wound areas, and avoid spraying directly onto your face.
- You can cover-up with clothing instead of using insect repellent, but you may still get bites. You can apply DEET or permethrin to your clothing; however, DEET may stain clothing. Sprays containing permethrin are available specifically for clothes, mosquito nets, sleeping bags, shoes, and hiking boots. Clothing that has permethrin imbedded can be purchased, as well.
- DO NOT apply permethrin directly to your skin.
Mosquitoes that cause West Nile Virus may be biting in the early morning (dusk) and at sunset (dawn), so be sure to apply repellent at these times. As long as you aren't getting bitten, there is no reason to apply more repellent. Be sure to follow instructions on the specific package of insect repellent you have purchased.
Insect Repellent Safety
Before they can be marketed, most skin-applied repellents must be registered by the U.S. Environmental Protection Agency (EPA). Active ingredient names such as DEET, picaridin, and permethrin have been shown to be effective in clinical trials and are registered with the EPA for use as insect repellents on skin or clothing.
When the EPA registers a repellent, they evaluate the product for effectiveness and potential side effects on humans and the environment. An EPA registered insect repellent is not expected to cause serious effects to humans or the environment when used as directed. The EPA evaluation assures that the product does not pose risks to vulnerable populations, including children and pregnant women. The CDC recommends that consumers use repellent products that have been registered by EPA.
Learn More from the EPA: Repellents: Protection against Mosquitoes, Ticks and Other Arthropods
Side Effects with Insect Repellents
- skin reactions or allergic rashes
- eye irritation, especially if it gets into the eye
- if the repellent gets into your eyes, immediately flush your eyes with water and contact your doctor or Poison Control Center.
- serious side effects to insect repellents are uncommon if directions are followed.
If you think you are having an adverse reaction, discontinue use of the product, wash the affected area with soap and water, and call 911 or contact a Poison Control Center (National Poison Control Center 1-800-222-1222).
Be sure to take the insect repellent bottle with listed ingredients to any doctor you may visit.
Can I Use DEET and a Sunscreen at the Same Time?
Yes -- sunscreens and insect repellents with DEET can be applied at the same time, but there are some special considerations.
- apply the sunscreen first, followed by the insect repellent containing DEET and follow the directions for each product.
Some repellents are available with a sunscreen in the mixture already, but these products are no longer recommended by the CDC. Reapplying the combination sunscreen-repellent product too frequently may lead to toxic side effects due to the repellent. Limited data have shown that use of DEET with sunscreens may lower the effectiveness of the sunscreen or sun protection factor (SPF) by up to one-third.
In general, the recommendation is to use separate products. First, apply the sunscreen and then apply the repellent. Due to the decrease in SPF when using a DEET-containing insect repellent after applying sunscreen, you may need to reapply the sunscreen more frequently.
Insect Repellents and Children
The label that is on the container of the insect repellent must state the age limits for children; if no age limits are noted then the repellent can be used in any age range. According to the CDC, most repellents can be used on children aged >2 months.
- Oil of Lemon Eucalyptus should NOT be used on children under 3 years.
No serious illness has been linked to the use of DEET in children when used as directed. DEET is the only repellent with recommendations for children from The American Academy of Pediatrics (AAP). The AAP states “insect repellents containing DEET with a concentration of 10% appear to be as safe as products with a concentration of 30% when used according to the directions on the product labels.” The AAP recommends that insect repellents NOT be used on infants less than 2 months of age.
Parents should choose a repellent based on the amount of outdoor time, exposure to mosquitoes, and risk of mosquito-transmitted disease in the area.
When applying insect repellent to children:
- apply to your own hands then rub onto the child; do not allow a child to apply it themselves
- avoid a child’s eyes, mouth, and use sparingly around ears
- do not apply repellent to areas with open wounds
- do not apply repellent under clothing; wash treated clothing before wearing again
- wash the treated skin with soap and water when you have returned indoors
- keep repellents out of reach of children and pets.
Other ways to avoid mosquito bites
- wear long sleeves and long pants
- use mosquito netting over bed or seating areas. Protect infants 2 months or younger from mosquitoes by using mosquito netting with an elastic edge for a tight fit for a crib or infant carrier.
- applying permethrin to clothing and bedding (not skin)
- avoid areas of standing water.
Insect Repellent Safety in Pregnant and Nursing Women
According to the CDC, there are no additional precautions for pregnant or breastfeeding women; the standard safety tips and directions for use should be followed. As always, if you have questions or concerns, contact your healthcare provider.
A study from Harvard looking at DEET use as a protectant from Zika virus found that it is safe with few side effects if used properly. Several expert researchers also agree.
In addition, the American College of Obstetrics and Gynecology (ACOG) states that DEET is safe for use in pregnancy. Insect repellent use in areas with mosquitos carrying the Zika virus is critical. Zika infection during pregnancy can put babies at risk for death and birth defects including small brains (microcephaly), poor growth, and hearing or eyesight loss.
Other measures for Zika protection generally include covering arms and legs, using window screens and bed nets, and avoiding geographic areas where Zika is prevalent. To learn more about Zika virus, visit the CDC website for the latest information.
If you are concerned about using insect repellents you may want to contact your healthcare provider for additional advice. The National Pesticide Information Center (NPIC) can also provide information at 1-800-858-7378.
If internal consumption or other poisoning due to insect repellent has occurred call 911 or the National Poison Control Center at 1-800-222-1222.
- EPA: Insect Repellents: Use and Effectiveness
- CDC: Protection against Mosquitoes, Ticks, & Other Arthropods
- Drugs.com: It's Buggin Me! How to Safely Use an Insect Repellent
- CDC: FAQ: Insect Repellent Use and Safety
- Medications for Insect Bites
- Medications for Lyme Disease
- Medications for West Nile Virus
- Medications for Zika Virus Infection
Symptoms and treatments
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- CDC. West Nile Virus. Accessed April 8, 2021. https://www.cdc.gov/westnile/index.html
- Illinois Department of Public Health. Prevention and Control. DEET Insect Repellents. Accessed February 20, 2019 at http://www.idph.state.il.us/envhealth/deetfacts.htm
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- Insect Repellents. The Medical Letter. Vol 54 (1399). September 17, 2012. Accessed February 20, 2019.
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Oil of Citronella. Accessed April 8, 2021 at http://npic.orst.edu/ingred/citronella.html
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.