The most effective mosquito repellents are those applied directly to your skin or clothing, specifically products containing DEET, picaridin, or oil of lemon eucalyptus (OLE). Environmental strategies like fans and eliminating standing water help too, but nothing replaces a good topical repellent when mosquitoes are active. Here’s what works, what doesn’t, and how to layer your protection.
DEET and Picaridin: The Gold Standard
DEET has been used since 1946 and remains the most thoroughly studied repellent ingredient on the market. It works by interfering with the receptors mosquitoes use to detect your skin. Picaridin, developed more recently, performs comparably and feels less greasy on the skin.
The concentration you choose determines how long you’re protected, not how strongly the product repels. In field studies comparing the two, 25% DEET provided about 4 hours of 95% bite protection, while 25% picaridin stretched that to 5 hours. At higher concentrations, 20% picaridin and 33% DEET both delivered 100% protection for up to 10 hours. Lower concentrations still work but wear off faster: 10% picaridin protects for roughly 3.5 to 5 hours depending on the mosquito species.
For a typical backyard evening, a product with 15 to 25% of either ingredient is plenty. If you’re hiking all day or traveling somewhere with mosquito-borne disease, look for concentrations of 20% or higher. Both ingredients are safe for pregnant and breastfeeding women when used as directed.
Oil of Lemon Eucalyptus: The Best Plant-Based Option
Oil of lemon eucalyptus is the only plant-based repellent recommended by the CDC for use in areas where mosquitoes carry diseases like malaria. The active compound, called PMD, is refined from the leaves of the lemon eucalyptus tree. At a 30% concentration, it provided nearly 97% protection for 4 hours in a field study in Bolivia. A 50% concentration blocked 100% of bites for 6 to 7 hours in Tanzania, even against the aggressive species that transmit malaria.
One important restriction: products containing OLE or PMD should not be used on children under 3 years old. For older kids and adults, it’s a solid alternative if you prefer to avoid synthetic ingredients.
A Tomato-Derived Repellent Worth Knowing
A lesser-known option is 2-undecanone, a compound originally found in wild tomato plants and now sold under the brand name BioUD. It’s registered with the EPA and performed on par with low-concentration DEET in testing. Against Asian tiger mosquitoes, 7.75% 2-undecanone matched both 7% and 15% DEET over a 6-hour period. On treated clothing, it remained as effective as 7% DEET for up to 8 days. It’s not as widely available as DEET or picaridin products, but it’s a legitimate option if you see it on the shelf.
Permethrin-Treated Clothing
Permethrin is an insecticide you apply to clothing, shoes, and gear rather than your skin. It kills or disables mosquitoes on contact, which means they don’t just avoid your clothes, they die when they land on them. You can buy pre-treated clothing or spray your own with a permethrin product and let it dry before wearing.
Treated clothing stays effective through multiple washes, though the exact number varies by product, so check the label. Pairing permethrin-treated clothing with a skin-applied repellent on exposed areas gives you the most complete coverage. This combination is standard advice for anyone spending extended time outdoors in mosquito-heavy environments.
Fans: Surprisingly Effective Outdoors
Mosquitoes are weak fliers, and a simple fan can make it significantly harder for them to reach you. Moving air disrupts their flight and disperses the carbon dioxide and body odors they use to track you. Oscillating fans and box fans work best outdoors because they push air over a wider area. A small desk fan is better than nothing, but it won’t cover much ground.
If you’re sitting on a patio or deck, placing a fan at ground level near your feet and ankles (where many species prefer to bite) can make a noticeable difference. It won’t replace repellent, but it’s a practical layer of protection that costs nothing to run.
Citronella Candles: Limited Protection
Citronella candles are one of the most popular mosquito products sold, but the science behind them is underwhelming. In a controlled study, citronella candles reduced mosquito bites by about 42% compared to having no candle at all. Citronella incense performed even worse, cutting bites by only 24%. Notably, plain candles (with no citronella) also reduced bites to nearly the same degree as citronella incense, likely because the heat and smoke alone provide some deterrent effect.
Citronella oil evaporates quickly, which is the core problem. The active compounds work in the moment but don’t linger the way a skin-applied repellent does. A citronella candle on your patio table might take the edge off, but don’t count on it as your only line of defense.
What Definitely Does Not Work
Ultrasonic mosquito repellent devices, those small plug-in or clip-on gadgets that emit high-frequency sounds, are completely ineffective. A systematic review of 10 field studies found zero difference in mosquito landing rates whether the devices were on or off. In fact, 12 out of 15 individual experiments found that landing rates were actually higher when the device was running. The supposed mechanism, mimicking the wingbeat of male mosquitoes to scare off biting females, doesn’t hold up to scrutiny. These devices should not be purchased or relied upon.
Reducing Mosquitoes Around Your Home
Repelling mosquitoes from your body is half the equation. The other half is reducing the population near where you live and spend time outdoors. Mosquitoes breed in standing water, and they don’t need much of it. A bottle cap’s worth of water can support larvae. Walk your property weekly and dump out saucers under flower pots, old tires, clogged gutters, birdbaths, and anything else that collects rainwater. Birdbaths and pet bowls should be refreshed every few days.
Keeping grass and vegetation trimmed removes the shady resting spots where adult mosquitoes spend the hottest parts of the day. If your yard borders a wooded or marshy area, treating the perimeter with a barrier spray can help, though these need to be reapplied regularly.
Using Repellents Safely on Children
EPA-registered repellents containing DEET, picaridin, or 2-undecanone are safe for children of all ages when used as directed. OLE and PMD products are the exception, restricted to children 3 and older. For any repellent, avoid applying it to a child’s hands, eyes, mouth, or any broken skin. The easiest way to apply repellent to a young child’s face is to spray it on your own hands first, then gently rub it on.
Sunscreen should go on before repellent. Combination sunscreen-repellent products aren’t ideal because sunscreen needs more frequent reapplication than repellent does, which can lead to overexposure to the active repellent ingredient.