The most effective mosquito repellents are EPA-registered products containing DEET, picaridin, IR3535, or oil of lemon eucalyptus. These are proven safe for most people, including pregnant and breastfeeding women, and they range from about two hours to twelve hours of protection depending on the ingredient and concentration. Beyond sprays and lotions, spatial devices, fans, and yard management can all reduce your exposure.
DEET: The Longest Track Record
DEET has been the standard mosquito repellent since the 1950s, and it remains one of the most effective options available. Protection time scales with concentration: a product with 10% DEET protects for roughly 2 hours, while 30% DEET extends that to about 5 hours. Higher concentrations last longer but don’t repel more effectively at any given moment. Overall, DEET products can provide anywhere from 2 to 12 hours of mosquito protection depending on the percentage.
For a short walk or a backyard dinner, a lower-concentration product works fine. If you’re hiking, camping, or spending a full day outdoors, look for 20% to 30%. Going above 30% adds diminishing returns for most situations. DEET is safe on skin and clothing, though it can damage certain plastics and synthetic fabrics like rayon.
Picaridin: Effective Without the Sticky Feel
Picaridin (sometimes labeled icaridin outside the U.S.) is the main alternative to DEET, and at equal concentrations it performs comparably. A product with 20% picaridin provides 8 to 12 hours of protection, making it one of the longest-lasting options you can buy. It’s odorless, non-greasy, and won’t damage plastics or gear, which makes it popular with hikers and travelers. You’ll find it in sprays, lotions, and wipes from brands like Sawyer and Natrapel.
Oil of Lemon Eucalyptus
Oil of lemon eucalyptus (OLE) is the one plant-derived repellent that has earned full EPA registration, putting it in the same category as DEET and picaridin for proven effectiveness. It contains a compound called PMD that mosquitoes strongly avoid. At 30% concentration or below, OLE products have no age restrictions. At higher concentrations, labels typically advise against use on children under three. Protection time is shorter than high-concentration DEET or picaridin, so plan on reapplying more frequently.
One important distinction: oil of lemon eucalyptus is not the same thing as lemon eucalyptus essential oil. The refined, EPA-registered version undergoes processing that concentrates the active compound. The raw essential oil does not offer the same level of protection.
Why Most Essential Oils Fall Short
Citronella candles, peppermint spray, lavender oil, and similar natural products are among the most commonly purchased repellents, but testing consistently shows they provide very brief protection. Research at New Mexico State University tested 20 essential oil ingredients in a 10% solution. Clove oil, cinnamon oil, and geraniol oil were the best performers, each lasting just over one hour. Citronella and lemongrass lasted about 30 minutes. That means reapplying every half hour to maintain any meaningful barrier.
These oils aren’t useless if you’re sitting on your porch for 20 minutes, but they’re a poor choice for any extended outdoor activity, especially in areas where mosquitoes carry diseases like West Nile virus, Zika, or dengue. If you prefer plant-based options, EPA-registered oil of lemon eucalyptus is the better bet.
IR3535: A Lesser-Known Option
IR3535 is an EPA-registered active ingredient found in some Avon Skin-So-Soft products and a handful of other brands. It’s been widely used in Europe for decades. The drawback is duration: a 7.5% IR3535 product provided only about 23 minutes of complete protection in University of Florida testing. Higher concentrations may perform better, but IR3535 products on the market generally don’t match the protection time of DEET or picaridin at standard concentrations. It’s a viable ingredient, but read the label carefully and expect to reapply often.
Spatial Repellents and Fans
Spatial repellent devices like Thermacell heat a small mat or liquid cartridge to release an insecticide vapor into the air around you. These work best in calm conditions with little wind. Testing shows over 90% protection within about 3 feet of the device, dropping to around 55% at roughly 10 feet. They’re popular for patios, campsites, and fishing spots where you’re staying in one area. They do affect non-target insects, so use them thoughtfully near gardens or water features where beneficial species live.
A surprisingly simple tool is a fan. Mosquitoes are weak fliers, with top speeds between 0.9 and 3.6 miles per hour. A basic box fan or oscillating fan on a porch creates enough airflow to physically prevent them from reaching you. It also disperses the carbon dioxide plume your body produces, which is the primary way mosquitoes locate you from a distance. Positioning a fan at ground level near your legs and feet (where mosquitoes tend to approach) can dramatically reduce bites with zero chemicals.
What Doesn’t Work
Ultrasonic repellent devices, those small plug-in or clip-on gadgets that claim to emit high-frequency sound waves, have no reliable evidence behind them. Researchers at McGill University reviewed the available science and concluded that commercially available ultrasonic devices are “pretty much useless.” Some animals may briefly react to ultrasound, but mosquitoes don’t appear bothered, and any initial response tends to fade as they habituate to the noise. Save your money.
Vitamin B1 supplements, garlic consumption, and wristbands infused with repellent have also failed to show meaningful protection in controlled testing. Citronella candles reduce bites slightly compared to having no candle at all, but the effect is minimal and inconsistent once any breeze picks up.
Choosing the Right Repellent for Your Situation
Your best choice depends on how long you’ll be outside and how heavy the mosquito pressure is. For quick yard work or a short walk, a low-concentration DEET product or a citronella-based spray may suffice. For anything over an hour, 20% picaridin or 25% to 30% DEET gives you the most reliable, longest-lasting coverage. Oil of lemon eucalyptus is a strong plant-based middle ground.
For backyard gatherings, combining a spatial device like Thermacell with a fan near seating areas creates a layered defense that works well. Removing standing water from gutters, plant saucers, and bird baths eliminates breeding sites and reduces the local population over time. Even a bottle cap’s worth of stagnant water can produce mosquitoes.
When applying any repellent to skin, spray it on your hands first and then rub it on, avoiding eyes and mouth. Apply sunscreen first, then repellent on top. If you’re using both, you may need to reapply sunscreen more often since repellents can reduce its effectiveness. For children, adults should apply the product to their own hands and then rub it onto the child, keeping it away from small hands that end up in mouths.