11-minute read

Key takeaways

• Effective insect protection: Permethrin-treated clothing provides long-lasting protection against a wide range of insects, reducing the risk of bites and insect-borne diseases while hiking.
• Safety and usage: Permethrin is safe for humans when used as directed and can be applied to clothing, gear, and tents. It remains effective for multiple washes, making it a practical choice for hikers.
• Environmental considerations: While permethrin is effective, it should be used responsibly to minimize environmental impact, as it can be toxic to aquatic life and beneficial insects if not used correctly.

In a hurry? Click to jump to a section below:

What is permethrin?
How does permethrin work?
How do I use permethrin?
Is it cheaper to buy permethrin clothing or treat my own?
Is permethrin safe?
What else can I use to repel insects?
How likely am I to get bitten by a tick or a chigger?
Why do I get bitten by mosquitoes?
What can I wear to reduce bites?
FAQs

What is permethrin and how is it useful when hiking? Permethrin is an insecticide used to prevent insect bites. You can buy ready-treated permethrin clothing. You can also buy permethrin in spray, aerosol or concentrate so you can treat your own clothes.

Hikers wear permethrin clothing to reduce the risk of diseases and symptoms caused by tick and mosquito bites. Permethrin clothing also helps reduce bites from many other insects.

I’ve used insect repellents such as DEET many times. Permethrin adds an additional layer of protection. I’ve spent several days researching the science behind permethrin clothing so I can explain clearly to you: how it works, if it is safe, and how effective it is. You’ll also read here about alternatives to permethrin clothing. And I’ve thrown in some facts about the prevalence of ticks in the USA.

What is permethrin?

Permethrin is an EPA-registered insecticide that kills insects such as ticks, mosquitoes, chiggers and mites. You can treat your hiking clothing and gear with it so that if insects land on the treated material, they die and fall off before they have chance to bite you. You can also buy pre-treated hiking clothing. Don’t spray permethrin on the skin. It won’t repel insects, but it will kill them or make them drop off. You can still use an insect repellent on your skin as well as treating clothes with permethrin.

Permethrin is a manmade version of pyrethrin, which is a natural insecticide in chrysanthemum flowers. It was first used by the military in the 1990s. Permethrin is used in several sectors: in agriculture to protect crops and kill livestock parasites; for insect control in industrial and domestic settings; to protect woollen clothing in the textile industry; in aviation to disinfect aircraft; in dog flea collars (not in cat collars – it’s toxic to cats); for treating timber; and also as a treatment for head lice and scabies.

How does permethrin work?

Insects that land on permethrin-treated clothes will die or become incapacitated. Permethrin affects their central nervous system. There are several brands of permethrin clothing spray made by Sawyer, Repel, Ranger Ready, Ben’s and more. They come as pump sprays or aerosols. Permethrin provides an odorless barrier of protection. A single application lasts for six weeks or six washings. It protects against more than 55 kinds of insects, including the Yellow Fever Mosquito, which can transmit the Zika Virus. The CDC advices using permethrin to stop ticks that can transmit Lyme Disease and Rocky Mountain Spotted fever.

You should permethrin in conjunction with an insect repellent such as DEET or picaridin to maximise protection from mosquitoes and ticks. 

One study concluded that permethrin was more effective at reducing mosquito bites in a camping setting than insect repellent alone. Another study also found that permethrin-treated clothes reduced mosquito bites. Results vary depending on the method used to treat clothing, mosquitoes’ resistance to pesticides, and the species of mosquito. See the science here, here and here. 

The organization Consumer Reports tested clothing brands pre-treated with permethrin to learn how effective each brand was at stopping mosquito bites. They found that only half of the tested brands stopped the bites. In another test, they found a shirt sprayed with DEET to be more effective than the pre-treated permethrin clothing.

What about stopping tick bites? One study evaluated 82 outdoor workers over two years; 40 used permethrin-treated clothing and 42 did not. Of those using treated clothing there were 60 tick bites. The 42 workers without permethrin clothing reported 166 tick bites.

Another study also compared two groups – one wearing permethrin-treated outfits and another group with untreated clothing. Both groups then had ticks placed on them and left for two hours. Subjects wearing treated outfits had 3.36 times fewer tick bites than those wearing untreated clothing. There was no difference between the effectiveness of treat-at-home clothing and ready-treated clothing. Treating footwear gave the best protection. Even when ticks did attach to clothing, most that attached to the permethrin clothing died. 

Researchers also monitored tick bites on forest workers. Outdoor workers wearing treated clothing had 0.24 bites per 100 hours’ work. Non-protected workers had 1.37 bites per 100 hours’ work.

In a nutshell, permethrin is effective at preventing insect bites, including mosquito and tick bites.

How do I use permethrin?

You can buy clothes already treated with permethrin. Or, you can treat your clothes and gear yourself. There are two methods: spraying or soaking. It’s cheaper to buy a concentrated bottle of permethrin, and make your own soak solution. But this method will take more time, and you have to be careful to use the correct amount. 

Permethrin will bind better with absorbent clothing such as cotton. It will still work on waterproof clothing, but not quite as well, and it will wear off quicker. It won’t damage the waterproof surface. It’s very unlikely a tick or mosquito could bite you through waterproof clothing anyway.

Tip! If you treat your clothes with a waterproofing spray, do that first before the permethrin. Then permethrin will be the top layer. 

How to spray your clothes with permethrin

Make sure the spray you buy is specifically for treating clothing. Always follow the instructions on the label. Don’t buy permethrin agricultural pesticide and dilute it down; that is illegal. The agricultural permethrin won’t stick to your clothes either. 

To protect yourself wear rubber or latex gloves, and stand upwind of the spray so it can’t blow into your face. Wear a mask. Spray outdoors in a shaded area. Either lay clothes flat or hang them up.

Sawyer permethrin spray bottle instructions state: “To apply, spray Permethrin directly onto clothing and gear with a slow sweeping motion, keeping the bottle about six to eight inches away and treating each side of the garment for about 30 seconds”.

The EPA says do not spray underwear. Do spray shoes and backpacks. Do not spray the clothes while you are wearing them. Spray until the clothes are damp all over. Leave the clothes to dry for two hours, or more if it’s a humid day. Sunlight breaks down permethrin so don’t leave them in direct sunlight. 

Tip! Do not spray near cats, bees, aquatic life or ponds! Permethrin is toxic to cats, insects and aquatic life.

Manufacturers’ guidelines say that you’ll need to treat the clothes after every six washings, or every 42 days – whichever comes first. Always wash permethrin-treated clothes separately from other clothes.  

How to soak your clothes in permethrin

Soaking is an effective method if you have a lot of clothes or bulky items to treat. Other websites recommend using Martin’s permethrin. They tell you to dilute 10 percent permethrin concentrate at a ratio of one part permethrin to 20 parts water. Read the label! I don’t recommend buying any permethrin concentrate that isn’t for clothing. Martin’s bottles state they are only for use by licensed pest control officials or commercial applicators. 

Another brand, Duration 10% states that it is for treatment of clothing and bed nets. Also, that it “is the only EPA registered permethrin concentrate available”. It’s not always available on Amazon, but keep checking back.

Wear rubber or latex gloves and a mask to protect yourself. You can either soak the clothes in a bucket or soak individual items in Ziplock plastic bags. With a bucket you’ll have some waste product and you’ll have to remember to wash the bucket afterwards. Using Ziplock plastic bags you won’t have as much waste product. But if you don’t plan to re-use the plastic bags, you’ll have waste plastic.

If using plastic bags, start with 3oz of liquid per item of clothing. Close the bag and squeeze it to ensure the solution soaks into the fabric. Add more solution if the fabric still has dry spots. Make sure the permethrin cannot leak from the bag.

If the clothes are in a bucket or a bag, leave them to soak for about an hour (depending on the instructions). Be sure that no animals or children can get to the bucket.

Find a well-ventilated space away from animals and children. Wear gloves to remove the clothing and hang it or lie it flat to dry.

When your treated clothes are dry, store them in sealed black plastic bags. Air and light break down permethrin, so this keeps it active for longer. Air and light break down permethrin, so this keeps it active for longer.

Tip! Don’t want the hassle of treating your own clothes with permethrin? Send them to the Shield Technology company and let them do it for you! They only treat clothes, not gear, nor underwear. The service takes three to five business days. Once treated, clothes do not need reapplication.

How to dispose of permethrin

To dispose of permethrin, follow the guidelines on the bottle or the EPA’s official advice. Do not pour it down the drain or tip it where it could get into ground water because it is toxic to many animals. Some people leave it in sunlight in a bucket until it evaporates. If you do that, make sure no animals or children have access to the bucket.

Is it cheaper to buy permethrin clothing or treat my own?

It’s cheaper to buy pre-treated clothing because the treatment lasts up to 70 washings – much longer than DIY treatments. It’s also zero hassle and there’s no risk of accidentally inhaling the permethrin or spilling it onto your cat! 

Also, retailers like REI often have discounts on permethrin clothing. REI advise that the treatment lasts for 70 washes. At the time of writing men’s treated pants cost $60. That means the cost of buying these treated pants is 86 cents per wash until the treatment runs out ($60 divided by 70 washes). And that cost includes the cost of the actual pants, not just the permethrin treatment.

If you’re treating your pants yourself and you buy a 24oz spray bottle of Sawyer it costs $17. Plus, you’ve paid for the pants. The instructions say that one bottle will treat five complete outfits (shirt, pants, socks). Let’s say that half the spray goes on the shirt and socks and the other half on your pants. So, if you only treated your pants, then one 24oz bottle would treat your pants 10 times. One treatment lasts for six washes. You could wear and wash the pants 60 times, so 60 weeks. That equals $1.70 per treatment.

Other brands that make permethrin-treated hiking clothing include Burlington, L.L. Bean, Insect Shield, and ExOfficio.

Is permethrin safe?

Is permethrin safe? Well, not for insects!

Permethrin is safe for humans if you follow the instructions on the bottle. Don’t spray it onto your skin, and don’t ingest it. If you have sensitive skin, you could get a rash if permethrin-treated clothing touches your skin.

The Environmental Protection Agency (EPA) in the USA states that it could be carcinogenic when ingested. This is based on studies done with mice. According to the EPA, the level of permethrin in treated clothing is too low to negatively affect human health. They state that it is also safe for pregnant women. Tests of permethrin-treated fabric have concluded that it doesn’t leach much onto the skin.

Studies of soldiers wearing permethrin clothing, and textile workers who handle the clothing show the risk of adverse health effects from permethrin to be very low.

A permethrin fact sheet from the National Pesticide Information Center notes that permethrin is highly toxic to cats, fish and other aquatic species because they cannot metabolise the toxins as rapidly as humans.

The Tick Encounter Center has a factsheet on permethrin which explains that a 140lb person can be exposed to 32 grams of permethrin daily without adverse health effects. A 24oz bottle of permethrin contains 3.4 grams (0.5 percent) of permethrin. Toddlers are also safe to wear permethrin-treated clothing because the exposure risk is 27 times below the EPA’s Level Of Concern (LOC).

If you do get permethrin spray on your skin, the manufacturers advise washing the area for 20 minutes and then contacting poison control. Don’t buy permethrin containing petroleum distillates. These chemicals will leave a greasy film. This PDF from the EPA describes all the risks of permethrin. 

But, in the EU permethrin’s use as an agricultural pesticide is banned. In the USA it is permitted. Other uses of permethrin in the EU are allowed.

When used as per the instructions, permethrin is safe for humans.

What else can I use to repel insects?

If you use permethrin on your clothes, you should still use an insect repellent on your skin.

If you don’t like the idea of using permethrin on your clothes, then you can use regular insect repellents on your clothes as well as your skin. 

The most common insect repellents contain either DEET, picaridin or lemon eucalyptus. Insect repellent keeps insects away so they can’t bite you.

Picaridin is a synthetic compound that resembles piperine, which is a naturally occurring alkaloid in black pepper. The skin absorbs less than six percent of picaridin sprayed on it.

The body breaks down and expels whatever it does absorb. There is no evidence to suggest that picaridin is carcinogenic. Picaridin is odorless.

DEET is a chemical used by the American public to repel insects since 1957. All DEET absorbed into the body through the skin is broken down and expelled through the urine. DEET is not carcinogenic. The American Academy of Pediatrics (AAP) does not recommend the use of DEET on children under two months. DEET should not be applied more than once per day on children. Any DEET used on children should be the lowest concentration available. Don’t apply DEET on children’s hands or the areas around the mouth or eyes.

Tests found that clothing sprayed with DEET actually prevented more mosquito bites than permethrin-treated clothing. The CDC says that insect repellents for the skin should be just as effective when sprayed on clothes. If using insect repellent on clothes, wash them after each use and re-apply the repellent every time you hit the trail. Check the label on insect repellents to find out if it is likely to damage fabric. 

Using DEET repellents and permethrin-treated clothing together gives almost 100 percent protection against insect bites.

Lemon eucalyptus is a natural oil from a tree and one of its uses is as an insect repellent. The CDC has endorsed it. Applying lemon eucalyptus oil up to three times daily may reduce tick bites by about 65 percent. It is also effective against mosquitoes. An Australian study found that a 40 percent DEET formulation provided 100 percent protection against mosquitoes for seven hours. A 32 percent lemon eucalyptus oil solution provided 95 percent protection for three hours. Lemon eucalyptus oil is safe as long as you don’t swallow it. It can be used on children older than three years. Commercial products with a 30 percent concentration of lemon eucalyptus oil provide the best all-round protection.

An EPA-approved chemical called metofluthrin also acts as a mosquito repellent. But you don’t rub it on your skin. You clip it to your belt and a battery-powered fan disperses the repellent in the air around you. Researchers have also tested natural repellents including citronella, cedar, peppermint, lemongrass, soybean oil and geranium. Many of these offer short-term protection.

Can’t decide? Use the EPA’s tool to find which repellent is right for you.

How likely am I to get bitten by a tick or a chigger?

You can get bitten by a tick in your own backyard, as shown by this study conducted in Maine. Most people who found ticks on their body were gardening. Ticks wait alongside paths. They hold onto grasses with their third and fourth legs, and reach out with their first pair of legs. This is called ‘questing’. They can sense the body heat, moisture or vibration of a person or animal nearby. If that person or animal brushes against them, they climb onboard. 

In 2020, there were approximately 57.81 million people in hiking in the United States. The CDC says that annually about 35,000 cases of Lyme Disease are reported. But, it’s likely that up to 476,000 Americans get Lyme Disease each year.

This map shows the prevalence of tick-borne diseases across the USA. Not all ticks are infected with diseases, and not all species of tick spread disease. Lyme Disease is spread by the black-legged tick (or deer tick). Immature ‘nymph’ ticks transmit more disease than adult ticks because they are harder to see. Ticks attach to hard-to-see parts of the body such as the scalp, groin and armpits. The ticks can feed on your blood for up to 48 hours before the bacteria that causes illness is transmitted. Nymph ticks feed during spring and summer. Adult ticks are more active in the cooler months. You can learn more from the CDC here.

Where do ticks live?

Ticks can be found across the entire United States, but their prevalence is highest in regions with high humidity and moderate to high temperatures. Here are the areas where ticks are most commonly found:

Tip! Click here on the CDC’s site to see tick surveillance maps and info about where ticks are prevalent.

I once found a tick stubbornly clinging to my arm. I had no symptoms. I phoned the doctor and she arranged for a prescription of strong antibiotics. To remove the tick, I ran my arm under a constant jet of water. When it realised it couldn’t breathe any more, it came out. I flicked it away and we all lived happily ever after.

Horror! You’ve found a tick clamped onto you. What do you do? Better than my water-jet method – remove it with fine-tipped tweezers. Pull up gently and do not twist. Clean the area once the tick is out. Do not squish the tick with your fingers. You can flush it down the toilet. Learn more about how to remove a tick by following the CDC’s guidelines.

If you want to know everything there is to know about Lyme Disease, see the CDC’s FAQ.

Chiggers

Chiggers (Trombiculidae) are mites that bite and can cause severe itching. They are not dangerous in the USA. They are more serious in Asia. Use over-the-counter treatments recommended by your pharmacist to treat the itching. Wash clothes in hot (125-degree F) soapy water. To dislodge chiggers from your skin, take a hot bath or shower. 

Why do I get bitten by mosquitoes?

Genetics account for 85 percent of our susceptibility to mosquito bites, says WebMD. Aside from that, high levels of steroids or cholesterol on the skin attract mosquitoes. Uric acid and exhaled carbon dioxide also draw them in. They can smell you from 50 meters away. 

What can I wear to reduce bites?

The American Mosquito Control Association (AMCA) advises wearing long sleeves, long pants, and light-colored, loose-fitting clothing. Mosquitoes prefer dark colors, and can easily bite through tighter-fitting clothes.

Tip! Don’t wear scented lotions or perfumes! They attract mosquitoes.

If you’re hiking in an area where mosquitoes are rife, then use a mosquito head net and hat to protect your whole head.

Permethrin clothing essential points

Yes, there are ticks, mosquitoes and other biting insects out on the hiking trail. But you can avoid being eaten alive if you wear permethrin clothing and use an insect repellent. Wear long sleeves if it’s not too hot. And, stick to lighter colors. If you treat your own clothing with permethrin, remember it only lasts for six washings or 42 days. Always follow the instructions when treating your own clothing. Buy permethrin clothing and it lasts for 70 washes.

FAQs

What is permethrin-treated clothing?
Permethrin-treated clothing is apparel that has been treated with permethrin, a synthetic insect repellent, to protect against bites from mosquitoes, ticks, and other insects.

How effective is permethrin clothing in repelling insects?
Permethrin clothing is highly effective, providing long-lasting protection against a wide range of insects, and remains effective even after multiple washes.

Is permethrin-treated clothing safe to wear?
Yes, permethrin-treated clothing is safe for humans when used as directed, but it should not come into contact with cats, as permethrin can be toxic to them.

How long does the insect repellent effect of permethrin-treated clothing last?
The insect repellent effect of permethrin-treated clothing typically lasts through several washes, with some treatments remaining effective for up to 70 washings.

Continue your hiking education!

Now you know about permethrin clothing, you can check out our related guides:

How much water should I drink per day when backpacking?
Why use trekking poles? The 101 guide you’ve been waiting for
Hiking snacks: 20+ easy, nutritious snacks for the trail
The benefits of being outside: Why nature is essential for well-being