Repelling Mosquitoes: What Science Says Does and Doesn’t Work

Permethrin-treated clothing was still effective after three months of wear, according to a study published in Parasites & Vectors, and a 2020 paper published in the Journal of Medical Entomology found that treated clothing is associated with 65 percent fewer tick bites. An earlier study from researchers in London found that wearing long-sleeved shirts and pants treated with the synthetic repellent reduced mosquito bites by 91 percent.

Katie Westby, a staff scientist in vector and disease ecology at Washington University in St. Louis, offers a word of caution.

Permethrin “should never be applied to skin; you treat your clothes with it,” she says. “It is harmful to pets, so it should be applied to clothing outdoors where animals will not come into contact with it.”

Switching up your wardrobe

Mosquitoes appear to use specific wavelengths on the visual spectrum to locate a target. Their preferred colors: red, orange, black and cyan (a greenish-blue), according to a study published by researchers at the University of Washington in the journal Nature Communications.

Opting for an outfit that is green, purple, blue or white — colors that mosquitoes avoid — could leave you with fewer bites during outdoor adventures.

Despite the potential for the color of your clothing to ward off mosquitoes, Westby says, “you would need to be completely covered for this to be an effective strategy to avoid bites.” But it can’t hurt to dress not to impress mosquitoes this summer.

Using insect repellent

Stick with the basics. Insect repellents that contain DEET are considered the gold standard when it comes to reducing bug bites and preventing mosquito-borne diseases.

The chemical signature in the insecticide interferes with the mosquito’s scent receptors, causing the insect to get confused and keep moving. DEET-based products provide longer-lasting protection than insect repellents with other active ingredients.

Given the complex interaction of body odor, personal care products, diet and activity level that can make you more — or less — attractive to mosquitoes, Vinauger says, “I would still recommend using a conventional mosquito repellent.”

Catnip essential oil

Mosquito repellents work, but not everyone likes the idea of using a synthetic product on their skin. Nepetalactone, a compound found in catnip, is an effective, nontoxic alternative.

Mosquitoes don’t like the smell of catnip, according to a 2024 study. When the essential oil was applied to the skin, it repelled mosquitoes for up to four hours after it was applied and proved just as effective as an insect repellent that contained 15 percent DEET. Researchers called it “an effective, cheaper and more sustainable alternative to [insect] repellents.”

Lawn treatments

Pest companies offer treatments that blanket the lawn with insecticides to reduce mosquito populations. The treatments can work, though studies show that rainfall, the equipment used and application techniques can make them less effective — and the results might only be temporary.

Treatments “only kill mosquitoes that are in your yard at the time of spraying,” says Deborah Landau, director of ecological management for the Nature Conservancy. “Mosquitoes typically fly 1 to 3 miles, so they can quickly repopulate your yard.”

Lawn treatments can affect the ecosystem. Landau notes that the chemical sprays kill all insects, including bees, fireflies, butterfly larvae and other pollinators. “Birds often pick up insects killed by insecticides, and eat them or feed them to their young,” she adds.

When it comes to kids and pets, the research isn’t clear, according to Landau. It’s best to read manufacturers’ instructions, ask questions and proceed with caution. 

3 things that don’t work

Citronella candles and plants

Citronella plants might look great in the garden , but they do little to deter biting bugs. Standing near the plants or having them in your garden doesn’t do much to keep mosquitoes at bay.

In fact, if you plant enough citronella, it could have the opposite effect. 

“Finding natural alternatives to chemicals for repelling mosquitoes is an attractive option,” Westby says. “[But] there is evidence that having dense and flowering vegetation will attract mosquitoes to your yard, as they like to rest in cool, humid habitat and take sugar meals from flowers.”

You can skip the citronella-scented candles, too. Despite their reputation, research published in the Journal of Insect Science found that citronella candles had “no effect” on reducing the number of mosquitoes.

Spreading coffee grounds

It’s common for coffee companies to offer used grounds to gardeners, and the nitrogen-rich remnants from a morning cup of coffee can improve soil structure, suppress common fungal diseases and provide nutrients for earthworms. But there is no solid research showing that it prevents mosquito bites.

Older research found that coffee-treated water (in birdbaths, for example) might deter mosquitoes from laying eggs in those spots. You should always empty standing water in your yard to prevent mosquitoes from laying eggs there. 

Using spatial repellents

Old-school mosquito coils and battery-operated devices that release insect repellents into the air are often used in enclosed or semi-enclosed spaces such as restaurant patios or screened porches. Although store shelves are stocked with spatial repellents of all kinds, their effectiveness is mixed.

The latest research shows that mosquitoes took fewer full blood meals. The insects bit and moved on before getting full, which led them to bite more frequently and to spend more time in areas with spatial repellents — and no one wants to spend their summer with more mosquito bites.

Bug zappers don’t work well on mosquitoes or other biting flies, according to University of Delaware researchers. But beneficial bugs, including pollinators, are often killed by bug zappers.

Editor's note: This article was originally published on June 16, 2023. It has been updated to reflect new information.