How to Safely Use Permethrin on Clothing

Hiking shoes and gear shown with a bottle of Insect Shield insect repellent permethrin spray

This insecticide can help prevent mosquito and tick bites. But you must use it properly.

A portion of this content has been adapted from Consumer Reports

When it comes to preventing bites from mosquitoes and ticks, remember: It's important to remain vigilant and stay protected when you head outdoors all year round. Insect Shield offers three solutions. In addition to our clothing with built-in insect protection, we offer permethrin spray that you can apply to clothing yourself, and our permethrin clothing treatment service: We add our patented permethrin treatment to the clothes you send to us!

Protect Yourself with Permethrin

When thinking of preventing bug bites, you might first consider insect repellents like those containing DEET. Using an effective repellent is indeed one of the best ways to keep biting bugs at bay.

However, the Centers for Disease Control and Prevention (CDC) recommends an additional strategy: treating your clothing with a pesticide called permethrin. While repellents keep bugs away, pesticides like permethrin kill them on contact.

What Is Permethrin?

Permethrin is a common insecticide categorized within the pyrethroid family. This chemical family includes compounds similar to natural chrysanthemum flower extract. This effective insect repellent is used in various settings, from flea collars for pets and ear tags for cattle to specially treated clothing, powders, and aerosol sprays for clothing and gear.

Permethrin-treated clothing, first developed for 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 pre-treated clothing (especially those that specialize in outdoor gear). You can also send your own clothing to Insect Shield, and they will treat your clothes with permethrin for you. If you’d prefer a do-it-yourself option, Permethrin sprays are 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, Ph.D., 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.

Here, we’ll explain why permethrin-treated clothing might be an option you want to consider for protection against ticks and mosquitoes, how to make sure you get the best protection, and how to treat clothing with permethrin the right way.

How Well Does Permethrin Treated Clothing Work?

Permethrin is “very irritating to [the mosquitoes],” says Joe Conlon, a former Navy entomologist and technical adviser to the American Mosquito Control Association. “It’s like they landed on an electric grid.” The permethrin-treated clothing also resulted in “knock downs,” meaning mosquitoes were incapacitated or killed after contact with the clothing. Other research has found that knock downs might reduce biting rates in a specific geographical area. The shirts we sprayed with DEET didn’t cause any knock downs, however, because no bugs ever landed on them.

While Consumer Reports hasn’t tested permethrin-treated clothing specifically for ticks, a recent CDC study found that various types of treated clothing incapacitated several tick species or caused them to fall off the fabric. Although this experiment didn't involve human subjects, it showed promising results in tick control.

Further research involving human subjects provides additional support. A 2014 study in North Carolina tracked tick bites among forest, park, and wildlife agency workers wearing permethrin-treated clothing. During the 2011 tick season (mid-March through September), those wearing treated clothing reported significantly fewer tick bites—0.24 bites per 100 hours of work—compared to those in untreated clothing, who averaged 1.37 bites in the same period.

For full protection, manufacturers recommend using permethrin spray on clothing and applying an insect repellent on exposed skin. Consumer Reports’ experts agree, emphasizing the importance of a dual approach for maximum defense against ticks.

How to Treat Clothing With Permethrin

Are you unsure how to use permethrin on clothes? Keep in mind that permethrin is a pesticide and must, therefore, be used carefully.

The most important thing to remember when spraying your clothing with permethrin is that you must follow the label on the product. If you don’t follow the label, 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, Ph.D., Consumer Reports' senior scientist. “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.

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.

General Step-by-Step Instructions on How to Use Permethrin Spray

Choose the Items You Want to Treat:
- Items that are great for spraying include:
Select an Outdoor Area:
- It’s best to choose a space that is well-ventilated and shielded from the wind to ensure proper application and safety.
Start Spraying Your Items:
- Hold the Can Upright: Keep the spray can upright, approximately 6-8 inches away from the item you're treating.
- Spray: Apply liberally covering the entire surface of the item until it is fully covered but not soaked.
- Let the Items Dry Before Use: Allow the treated items to air dry completely before wearing or using them.

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 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.
Spray enough, but not too much. Mather says he often sees people making the mistake of giving their clothes a quick spritz of permethrin. 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). You don’t need to drench them—to where they’ll drip if you wring them out—but they do need a thorough coat.
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. Professionally treated clothing by Insect Shield lasts up to 70 washes or the expected lifetime of the product. In contrast, self-applied permethrin spray does not last as long, typically requiring re-treatment after six washes or 60 days to maintain effectiveness.
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 using protection even during casual activities, like 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.
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. Not only is that illegal but it’s 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 still leave plenty of skin exposed and vulnerable to a bug's bite. To protect your exposed skin, use an effective insect repellent, such as one that contains 15 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.