In our full investigation into mosquito control, we covered a range of strategies — fans, repellents, eliminating standing water, and permethrin-treated clothing. That last one deserves its own deep dive, because it’s one of the most effective tools available, and few people use it.
Permethrin-treated clothing is the layer of protection you don’t have to think about. You put it on in the morning and it kills mosquitoes, ticks, and other biting arthropods on contact throughout the day — no spraying, no reapplying, no smell. The CDC, EPA, and US military all recommend it, for good reason.
This guide covers what permethrin is, how to use it, whether DIY spray or pre-treated clothing is right for you, and everything you need to know about safety and effectiveness.
See also our guide to mosquito repellents for the skin-applied side of this system.
What Is Permethrin
Permethrin is a synthetic pyrethroid insecticide — a lab-made version of pyrethrins, which are natural insecticides produced by chrysanthemum flowers. It works as a contact insecticide: when a mosquito, tick, or other arthropod lands on or crawls across treated fabric, permethrin disrupts its nervous system, causing paralysis and death within seconds to minutes (NPIC: Permethrin Treated Clothing).
This is a fundamentally different mechanism from repellents like DEET or picaridin, which work by making you smell unappealing to mosquitoes. Permethrin doesn’t repel — it kills. A mosquito can land on your treated shirt sleeve, but it won’t survive long enough to bite.
The EPA first registered permethrin in 1979 and approved it for use on clothing in 1990, initially for military applications (EPA: Repellent-Treated Clothing). The US military has been treating combat uniforms with permethrin for over 20 years to protect soldiers from vector-borne diseases in deployment zones worldwide. It remains the only pesticide EPA-registered for treating clothing.
Permethrin is also used in agriculture, veterinary medicine (spot-on flea treatments for dogs), and public health (mosquito net treatments distributed by the WHO for malaria prevention). The clothing-specific use is a small fraction of total permethrin use, but it’s the application most relevant to outdoor recreation.
DIY Treatment vs Pre-Treated Clothing
You have two options for getting permethrin on your clothes: spray it yourself with a consumer product, or buy clothing that’s been factory-treated.
DIY Spray: Sawyer Permethrin
The most widely available consumer product is Sawyer Permethrin Premium Insect Repellent — a 0.5% permethrin spray sold in 24-ounce trigger spray bottles. It’s available at most outdoor retailers (REI, Walmart) and online for about $15–20.
Cost per treatment: About $3–4 per full outfit (shirt, pants, socks). A single bottle treats 2–3 outfits (Wirecutter: Insect Shield Review).
Longevity: The label says protection lasts through 6 washings or 6 weeks, whichever comes first. A 2019 study in the Journal of Medical Entomology found that permethrin content declined with washing but remained effective against mosquitoes through at least 6 wash cycles (PubMed: Residual Effectiveness of Permethrin-Treated Clothing).
Pros:
- Low upfront cost
- Treat only what you need, when you need it
- Works on any fabric you own
- Good for seasonal use
Cons:
- Must re-treat every 6 weeks or 6 washes
- Takes 2–4 hours of drying time
- Requires outdoor or well-ventilated space for application
Pre-Treated Clothing: Insect Shield and ExOfficio
Factory-treated clothing uses a proprietary process that binds permethrin to fabric fibers at higher concentrations than spray treatments. The bond is more durable — Insect Shield claims protection for 70 washes or the life of the garment.
Insect Shield is the major treatment service in the US. They treat military uniforms, and their technology is used by ExOfficio (BugsAway line), L.L.Bean, and other outdoor brands. You can also mail your own clothes to Insect Shield via their Easy Pack service — a flat-rate envelope costs about $125 and fits several outfits (Wirecutter: Insect Shield Review).
ExOfficio BugsAway clothing comes pre-treated and is widely available. Expect to pay $60–100 per item (shirt, pants). The treatment lasts the life of the garment (about 70 washes), making it cheaper per wear than repeated spray treatments if you use the clothing regularly.
Pros:
- Protection lasts years, not weeks
- No setup or drying time
- Even, factory-quality coverage
- Better for frequent outdoor use
Cons:
- High upfront cost
- Limited to clothing you buy specifically for this purpose
- Overkill if you only need protection for one trip per year
Which Should You Choose?
| Factor | DIY Spray | Pre-Treated |
|---|---|---|
| Upfront cost | $15–20 per bottle | $60–100 per garment |
| Cost per wear | $3–4 per outfit per 6 weeks | $0.50–1 per wear over garment life |
| Longevity | 6 washes or 6 weeks | 70 washes (garment life) |
| Convenience | Moderate (spray + dry 2–4 hrs) | None (wear as-is) |
| Best for | Seasonal/recreational use | Regular outdoor exposure |
If you hike or camp a few times a year, the DIY spray is the practical choice. If you spend extended time outdoors — fieldwork, gardening, daily walks in tick habitat — pre-treated clothing costs less over time.
How to Treat Clothes at Home
If you’re using the Sawyer spray, the process is straightforward. Here’s the step-by-step.
What you need:
- 0.5% permethrin spray (Sawyer or equivalent)
- Gloves (nitrile or rubber)
- Outdoor space or well-ventilated area
- Clothes hangers or a drying line
- Drop cloth or newspaper (optional)
Step 1: Prepare your clothes Wash and dry the items you plan to treat. Permethrin bonds better to clean fabric. Set up your clothing on hangers or lay them flat in a well-ventilated outdoor area — away from pets, especially cats.
Step 2: Spray evenly Hold the bottle 6–8 inches from the fabric. Use a slow, sweeping motion to apply an even mist. Treat each side of the garment — front, back, sleeves, collar. The fabric should look damp but not soaked. Sawyer recommends about 4 seconds of spraying per square foot.
Step 3: Let dry Allow the treated items to dry completely — this takes 2–4 hours depending on humidity and fabric thickness. The permethrin binds to the fabric fibers as it dries. Do not wear the clothing until it is fully dry.
Step 4: Store or wear Once dry, the clothing is ready to wear. Store treated items separately from untreated laundry. When washing, wash treated items separately from other clothes for the first few washes, as small amounts of permethrin can come off in the wash (EPA: Repellent-Treated Clothing).
Re-treatment: Reapply after 6 washings or 6 weeks, whichever comes first. UV exposure from sunlight also breaks down permethrin over time, so items stored in direct sunlight may need more frequent treatment.
Safety Profile
Permethrin-treated clothing has an excellent safety record when used as directed. Here’s what the data says.
Human Safety
The EPA conducted a comprehensive risk assessment for permethrin-treated clothing, evaluating scenarios including toddlers wearing or mouthing treated fabric and military personnel wearing treated uniforms daily. All scenarios showed that permethrin factory-treated clothing is unlikely to pose any significant immediate or long-term hazard (EPA: Repellent-Treated Clothing).
Permethrin is poorly absorbed through the skin. The amount of permethrin in treated clothing is low, and exposure levels are well below EPA safety thresholds. The EPA found no evidence of reproductive or developmental effects from permethrin exposure, including for women who are pregnant or nursing.
The National Pesticide Information Center notes that when applied properly, permethrin binds tightly to fabric, resulting in minimal transfer to skin (NPIC: Permethrin Treated Clothing).
Cats
Permethrin is toxic to cats when wet. This is the most important safety consideration. Cats lack the enzyme (glucuronidase) needed to metabolize permethrin, making them highly sensitive to it (UF/IFAS: Effectiveness, Safety, and Use of Permethrin-Treated Clothing). Symptoms of exposure in cats include drooling, tremors, and seizures.
The key rule: Keep cats away from permethrin during application and while clothing is drying. Once the treated fabric is fully dry, the permethrin is bonded to the fibers and poses minimal risk to cats. The dry fabric does not transfer enough permethrin to cause harm.
Dogs
Permethrin is safe around dogs. It’s the active ingredient in many topical flea and tick treatments for dogs (K9 Advantix, etc.). Dogs can safely wear permethrin-treated clothing and be in the area during application, though it’s still good practice to keep them away from the wet spray.
Not for Skin
Permethrin spray is for clothing and gear only. Do not apply it directly to your skin. The EPA labels these products specifically for fabric treatment. The CDC also emphasizes this distinction: permethrin goes on clothes; DEET or picaridin goes on skin (CDC: About Permethrin-Treated Clothing and Gear).
Effectiveness Against Mosquitoes and Ticks
The CDC recommends permethrin-treated clothing as part of its primary prevention strategy for both mosquito and tick bites (CDC: Mosquito Prevention, CDC: Tick Prevention).
Against Mosquitoes
A 2020 CDC study on long-lasting permethrin-impregnated clothing found high initial protection against mosquito bites, with treated uniforms providing significant protection compared to untreated fabric (CDC: Long-Lasting Permethrin Impregnated Clothing). A separate military study found that soldiers wearing permethrin-treated uniforms were 46% more likely to report decreased mosquito bites compared to those in untreated uniforms (PubMed: Evaluating the Usability of Permethrin Clothing).
However, effectiveness depends on the mosquito species and their resistance status. A 2018 study in PLOS ONE found that permethrin-treated clothing was effective against a susceptible mosquito population but not against a permethrin-resistant one (PubMed: Permethrin Treated Clothing to Protect Outdoor Workers). This is an emerging concern — pyrethroid resistance is increasing in some mosquito populations worldwide.
Against Ticks
Permethrin is particularly effective against ticks, which crawl slowly across fabric and spend more time in contact with treated fibers. A CDC study found that long-lasting permethrin-impregnated clothing demonstrated high initial protection against bites from blacklegged ticks (Ixodes scapularis, the Lyme disease vector) (CDC: Protective Effectiveness of LLPI Clothing).
The CDC Yellow Book — the agency’s reference for travel medicine — notes that at a concentration of 0.5%, permethrin-treated clothing “repels and kills ticks, chiggers, mosquitoes, and other biting and nuisance arthropods” (CDC Yellow Book: Mosquitoes, Ticks, and Other Arthropods).
The Bottom Line on Effectiveness
Permethrin-treated clothing is not a standalone solution — no single method is. But as a layer in a defense system, it’s proven to reduce bites significantly. The combination of permethrin-treated clothing plus an EPA-registered repellent on exposed skin is what the military, CDC, and outdoor professionals all use.
What to Treat
Not every item of clothing needs permethrin treatment. Focus on the items that cover the most skin and are most exposed to vegetation — where mosquitoes and ticks wait.
Treat these:
- Shirts — long sleeves are ideal; treat the cuffs, collar, and torso
- Pants — especially the cuffs and ankle area (ticks climb from the ground up)
- Socks — treat to the top; tuck pants into socks in heavy tick areas
- Hats — treat the brim and crown; mosquitoes are attracted to the CO₂ you exhale, which rises
- Boots and shoes — treat the exterior (laces, tongue, fabric panels)
- Mosquito nets — permethrin-treated bed nets are the global standard for malaria prevention
Do NOT treat:
- Underwear — permethrin is for outer clothing only; the EPA specifically advises against treating underwear
- Skin — permethrin spray is not for skin application
- Mattresses or bedding (except nets) — not labeled for this use
- Synthetic technical fabrics — permethrin is generally safe on synthetics, but some very thin nylon or silnylon items may degrade; test on a small area first
Gear to treat:
- Backpacks (especially shoulder straps and back panel)
- Tents (outer fly and floor)
- Camp chairs and hammocks
The CDC recommends treating “boots, clothing, and camping gear” specifically (CDC: About Permethrin-Treated Clothing and Gear).
Combining With Repellents
The most effective personal protection system combines permethrin on clothing with an EPA-registered repellent on exposed skin.
The system:
- Permethrin on clothes: Shirt, pants, socks, hat — kills insects on contact
- Picaridin or DEET on skin: Face, neck, hands, and any other exposed areas — repels insects from landing
This division of labor makes sense: permethrin handles the covered parts of your body (where ticks crawl and mosquitoes land on fabric) while a skin repellent handles the uncovered parts. The EPA specifically notes that permethrin-treated clothing only protects the skin surface covered by the treated fabric — other exposed areas need their own repellent (EPA: Repellent-Treated Clothing).
Why this combination works best:
- Redundancy: If a mosquito lands on your treated shirt but finds an untreated gap near the collar, the skin repellent covers it
- Coverage: Ticks that crawl up your pant leg encounter permethrin before reaching skin
- Less repellent needed: With your torso and legs covered by treated clothing, you only need repellent on smaller exposed areas — less chemical on skin, lower cost
- Military standard: This is the system used by US armed forces for vector-borne disease prevention (NPIC: Permethrin Treated Clothing)
See our repellent guide for which skin repellent to choose based on your situation.
Common Questions
Does permethrin wash off?
Some permethrin comes off in the wash, which is why the label says to wash treated items separately from other clothes. But a significant amount remains bonded to the fabric — enough to remain effective through 6 washes for DIY treatments and up to 70 washes for factory treatments. The EPA requires manufacturers to submit efficacy data showing the treatment works for the claimed number of washes.
How long does a treatment last?
For DIY spray: 6 weeks or 6 washes, whichever comes first. UV exposure can shorten this, so store treated items out of direct sunlight. For factory-treated clothing: the manufacturer claims 70 washes or the life of the garment. A Journal of Medical Entomology study found that permethrin-treated clothing remained effective against mosquitoes through at least 6 washes, with declining but measurable protection beyond that (PubMed: Residual Effectiveness).
Can you treat any fabric?
Permethrin works on most fabrics — cotton, polyester, nylon, wool, and blends. The EPA has evaluated it for use on the full range of clothing materials. The spray label says to treat outer clothing only. Some very lightweight silnylon or ultralight tent fabrics may not absorb the treatment well, but standard clothing fabrics are fine.
What about dry cleaning?
Dry cleaning removes permethrin more effectively than washing. If you dry clean treated items, you’ll need to re-treat them. The label instructions assume machine washing at standard temperatures — dry cleaning solvent strips the permethrin from fabric fibers.
Can I use permethrin on my mosquito net?
Yes. Permethrin-treated bed nets are one of the primary tools for malaria prevention globally, with the WHO distributing millions annually. You can spray a bed net with the same Sawyer permethrin product, following the same instructions. Treated nets provide both a physical barrier and an insecticidal layer.
Is permethrin safe for children?
The EPA’s risk assessment for permethrin-treated clothing included scenarios for toddlers wearing and mouthing treated fabric and found no significant hazard. Permethrin-treated clothing is considered safe for children to wear. As with adults, the clothing should be fully dry before wearing. Do not allow children to handle the spray bottle or be present during application.
Do I still need sunscreen?
|Yes. Permethrin provides no UV protection. Apply sunscreen as you normally would, under your treated clothing or to exposed skin. The CDC notes that sunscreen should be applied before insect repellent if using both — the same principle applies here.
Permethrin-treated clothing is one of the most effective and least-used tools for mosquito and tick prevention. The upfront effort of spraying a few outfits is modest, and the payoff is a layer of protection that works all day without thinking about it. For anyone who spends time outdoors during mosquito or tick season, it’s worth doing.
This article is part of our mosquito control investigation. See also our guide to mosquito repellents for the full system on skin-applied protection.