This insecticide can help prevent some mosquito and tick bites. But you must use it properly.
Permethrin-treated clothing—designed to kill or disable bugs upon contact—has been available to the public since 2003.
By Catherine Roberts
Updated by Justin Krajeski
To keep bug bites at bay, the Centers for Disease Control and Prevention recommends treating your clothing with a pesticide called permethrin—pesticides kill or disable bugs on contact, while repellents help keep bugs away. Using bug spray is another important strategy, as is keeping your yard unfriendly to mosquitoes and ticks.
Permethrin-treated clothing, first developed by the military a few decades ago, has been available to consumers since 2003, and there are a few ways to use it.
• You can buy pretreated clothing from various manufacturers, especially those that specialize in outdoor gear.
• At least one company, Insect Shield, will treat your clothes with permethrin for you, if you mail them in.
• You can do it yourself: Permethrin spray is available for consumers to buy and apply to their own clothing and gear.
“If it’s used correctly, it works really well,” says Thomas Mather, PhD, director of the University of Rhode Island’s Center for Vector-Borne Disease, of treating clothing with permethrin yourself. But the key, he says, is to use it correctly, which not everyone does.
While professionally treating your clothes with permethrin means the permethrin on your garments will last longer and will coat your clothes more thoroughly, you can still treat your clothes with permethrin yourself to protect against ticks and mosquitoes if you follow the tips we’ve laid out for you below.
How Well Does Treating Clothing With Permethrin Work?
A number of studies have found that permethrin-treated clothing can help protect against mosquito bites, though results may differ depending on a variety of factors, such as the species of mosquito, the way the clothing is treated and laundered, and the level of pesticide-resistance among the mosquitoes.
Consumer Reports has also tested several brands of clothing pretreated with permethrin to find out how well they worked at stopping mosquitoes from biting. Two types we tested in 2016 kept mosquitoes from biting, but two didn’t. A shirt we sprayed with a deet-based repellent, meanwhile, kept mosquitoes from biting and kept them from even landing, something none of the permethrin-treated clothing items did.
Permethrin is “very irritating to [the mosquitoes],” says Joe Conlon, a former Navy entomologist and former technical adviser to the American Mosquito Control Association. “It’s like they landed on an electric grid.”
The permethrin-treated clothing also resulted in “knockdowns,” meaning mosquitoes were incapacitated or killed after contact with the clothing. The shirts we sprayed with deet didn’t cause any knockdowns, however, because no bugs ever landed on them.
And what about ticks? Consumer Reports’ testing hasn’t evaluated how well permethrin-treated clothing works against ticks. But other research shows permethrin can be effective against ticks. In one 2020 study of outdoor workers in Rhode Island and Massachusetts, there were a total of 60 tick bites over two years among the 40 workers who used permethrin-treated clothing, compared with 166 tick bites among the 42 workers who didn’t use treated clothing.
Manufacturers of permethrin spray for clothing note that because the spray is meant only for fabric and not for skin, for full protection people also need to use an insect repellent on their exposed skin. Consumer Reports’ experts agree.
How to Treat Clothing With Permethrin
The most important thing to remember when spraying your clothing with permethrin is that you must follow the instructions on the product label. If you don’t, you could be violating federal law, Conlon says. (Because permethrin is a pesticide, the Environmental Protection Agency regulates its use.)
It’s also important to follow the instructions on the label to ensure you’re using the pesticide as safely as possible, says Michael Hansen, PhD, a senior scientist at Consumer Reports. “It’s an endocrine-disrupting compound," he says. That means “if it gets into your system, there can be effects on the hormonal system."
The CDC notes that permethrin and related chemical compounds can cause serious health problems in people exposed to high doses. “You don’t want to be inhaling it or getting it directly on your skin," Hansen says. Hansen also says that some recent studies suggest permethrin and other synthetic pyrethoids may be linked to adverse effects at lower doses, too.
If you follow the directions on the label, however, the dose of permethrin you receive by wearing treated clothing is considered safe, even for pregnant women. (Higher concentrations of permethrin are used in medications for treating both head lice and scabies.)
Permethrin Safety Tips
Spray only your clothing. We said it before, but it’s worth repeating: Permethrin spray is only for your clothes and gear. Don’t apply it to your skin. And when treating clothes, stick to outerwear. The Environmental Protection Agency says that you shouldn’t treat underwear with permethrin.
Spray while the clothes are off your body. Hang them on hangers outside, and spray them down while they hang. Don’t apply permethrin to your clothes while you’re wearing them, and don’t apply permethrin indoors, where you could risk inhaling it.
Never spray around cats. Keep your feline friends away from the area while you’re treating your clothes because permethrin is highly toxic to cats. According to Sawyer, which makes permethrin products, treated clothing is not dangerous to cats once it has dried.
Spray enough, but not too much. Mather says he often sees people making the mistake of giving their clothes a quick spritz of permethrin, even while wearing the clothing. But it takes a slightly heavier hand for full protection. Mather says you should spray enough for your clothes to become damp (they should look a little darker in color) and not spray the clothing you’re wearing. You don’t need to drench them—to where they’ll drip if you wring them out—but they do need a thorough coat.
The product labels can help give you a good idea of how much to use. For example, the label on Sawyer’s permethrin aerosol spray says that a 4.5-ounce bottle will treat a shirt, a pair of pants, and a pair of socks.
Let the clothes dry completely. Before you wear them, they should be totally dry. That should take a few hours, depending on the humidity of the day.
Re-treat when necessary. Manufacturers of pretreated clothing say their products are still effective after many washes. But the clothes you treat yourself need to be re-treated much more often. Sawyer says you need to re-treat after six weeks or six washings, for example. Even clothes or gear you don’t wash need re-treating; Mather says he sprays his own and his family’s shoes monthly.
Actually wear them. Mather says some people say they’re saving their permethrin-treated clothing for heavy-duty camping or hiking. But ticks don’t live just in the deep woods. If you live in an area where ticks are common, he recommends wearing your treated garments even during casual activities, like gardening or taking your dog for a walk.
Consider treating other gear. Conlon says that camping gear like tents, backpacks, and hiking boots are also good candidates for treating with permethrin.
Wash treated clothing separately. Sawyer recommends hand-washing and air-drying, or using the gentle cycle on your washer and dryer to best preserve the protection.
Only use permethrin approved for clothing. That will be indicated on the label. You may be tempted to purchase permethrin pesticide (or related chemicals) meant for agricultural uses and dilute it down to a concentration of 0.52 percent, the industry standard for clothing. That is not only illegal but also risky, because you could make a mistake and end up with the wrong concentration. And there’s no guarantee it will work as well, Mather says, because the permethrin products meant for clothes are formulated with ingredients that help it stick to fabric. The agricultural products may not have those ingredients.
Don’t rely on permethrin alone. Using permethrin-treated clothing is one useful step to take for preventing bites. But it’s not the only one. Because permethrin goes only on clothes, if you rely on it alone, you may still be leaving plenty of skin exposed and vulnerable to a bug’s bite (if, say, you’re wearing shorts and short sleeves instead of long pants and long sleeves). To protect your exposed skin, use an effective insect repellent, such as one that contains 25 to 30 percent deet, 20 percent picaridin, or 30 percent oil of lemon eucalyptus. Make sure you apply it right, and remember you can use repellent on your clothing as well if you’d rather skip the permethrin.
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