Core Backpacking Clothing || Go Suit — Item 3: Bug Shirt

Peak mosquito season in the Yukon Arctic. The ExOfficio Halo Shirt, which is permethrin-treated and made of tightly woven nylon, kept bites to a minimum.

Peak mosquito season in the Yukon Arctic. The ExOfficio Halo Shirt, which is permethrin-treated and made of tightly woven nylon, kept bites to a minimum.

I learned the hard way that mosquitoes and blackflies can bite through my knit polyester and knit merino wool hiking shirts. Another lesson: A rain jacket is effective insect protection, but wearing one in the High Sierra during the middle of the day under a blazing sun is completely unbearable.

A better bug strategy is a dedicated bug shirt. It is Item 3 in my Core 13, a tight collection of backpacking clothing that can be mixed-and-matched to create appropriate systems for all 3-season conditions.

Bug defense options

There are two types of bug defenses:

1. Body armor, via a tightly woven polyester or nylon fabric through which bugs cannot bite. However, because such a fabric has less air-permeability than knits, I discourage using this type of shirt when the bugs are mild or non-existent.

2. Chemistry, specifically permethrin. Sawyer offers a permethrin-based spray treatment, but the performance of factory-treated fabrics such as BugsAway from ExOfficio and Insect Blocker from Columbia is longer-lasting, supposedly “the expected lifetime of the product.” Unlike the body armor approach, it is possible to have a permethrin-treated fabric with high air-permeability.

Fit & features

Regardless of the defense strategy, a bug shirt should have long sleeves, a high collar, and the ability to lock off potential entry points like sleeve cuffs and the neck. A long arm length, perhaps even with thumb loops, would help to protect the wrist and some of the hand, which is otherwise exposed. Venting features like a chest zip and button-front are a must.

To enhance the poor airflow of woven nylon shirts, some manufacturers add mesh vents under the arms and/or along the back. I think the performance benefit is marginal, and it’s entirely offset by the ease with which bugs bite through this type of fabric, especially if it is not permethrin-treated. In fact, I think the only bites I have received while wearing a bug shirt have been along these mesh panels.

These types of shirts are synonymous with “travel” shirts and thus always seem to be styled with large chest pockets. I never use these pockets and should probably cut them off, since the double-layer fabric makes my chest hotter.

My two bug shirts: the ExOfficio Halo, which has a tight weave and a pemethrin treatment; and the GoLite Paporoa, which is made of an untreated woven polyester.

My two bug shirts: the ExOfficio Halo, which has a tight weave and a pemethrin treatment; and the GoLite Paporoa, which is made of an untreated woven polyester.

Fabric close-up

Fabric close-up

My picks and suggestions

Based on personal experience, I can verify the bug-resistance of:

Pemethrin-treated woven nylon shirts such as the ExOfficio HaloI used this exact shirt on my Alaska-Yukon Expedition, and for two weeks in 2013 during peak mosquito season in the Alaska Range.

Non-treated woven polyester shirts such as the GoLite Paparoa Long-SleeveGoLite is no longer around and I have not seen this fabric used in other shirts, but it serves the point that a tightly woven shirt, even without a permethrin treatment, can offer an effective defense against bugs.

Pemethrin-treated knit polyester shirts such as the Ex Officio BugsAway Impervio Crew, which will have substantially better airflow and dry time than the aforementioned woven nylons and polyesters. Due to limited personal experience, I cannot verify that factory-treated permethrin will “last the expected lifetime of the product,” as is claimed. But I’ve witnessed its effectiveness when new.

If you love a shirt that you already own, you can turn it into a legitimate bug shirt through the aforementioned spray-on permethrin treatment or by sending the shirt directly to Insect Shield, which will give you a much longer-lasting defense.

On a very buggy trip in Alaska in late-June, Doug wore a pemethrin-treated knit polyester shirt from Columbia. It was new for the trip, and it seemed very effective. Long-term performance is unknown.

On a very buggy trip in Alaska in late-June, Doug wore a pemethrin-treated knit polyester shirt from Columbia. It was new for the trip, and it seemed very effective. Long-term performance is unknown.

Posted in on March 10, 2015


  1. Chris"Soggybottom" Vores on March 11, 2015 at 4:42 am

    Just adding another long sleeve shirt to the wardrobe. I will check out the Halo. Getting ready to do the High Sierra Trail and I hear bugs can be rough. Headed up there in late July early August. Thanks for the tips.

    • Andrew Skurka on March 11, 2015 at 7:57 am

      To be clear, you would not wear or carry a long-sleeve hiking shirt AND a bug shirt. If I expect frequent moderate pressure or worse, I just go with a bug shirt. It’s not ideal for the bug-free times, but it’s very bearable, whereas getting tortured by biting insects is not. If you desire the air-permeability of a normal hiking shirt but still have bug protection, consider treating your favorite hiking shirt with the spray-on permethrin treatment, or buy a permethrin-treated knit hiking shirt like the Columbia Insect Blocker Knit Shirt.

      Given the snow levels this year, the bugs will be completely gone by late-July. I would encourage you to follow exactly this gear list: High Sierra — Late Summer.

  2. Joe on March 11, 2015 at 8:20 am

    I’m very excited for this entire series as the last 2 years of my hiking have been in more of a weight conscience fashion and this season my goal is to dial in my clothing options to be both minimalist but also effective (avoiding ‘stupid light’). Would it be an effective option to use the #2 item (long sleeve shirt) from yesterday spray-on treated with permethrin? You obviously mention this as an option but I guess the question is how much MORE effective is a dedicated bug shirt? I’ve never been in a situation where I am swarmed with mosquitos and really not excited to learn this lesson the hard way.

    • Andrew Skurka on March 11, 2015 at 8:29 am

      A true bug shirt is extremely effective. As in, you won’t get bit.

      If you always backpack in areas with light or no pressure, a bug shirt is probably unnecessary. However, a permethrin-treated knit bug shirt has the potential to be no different in its performance than an untreated knit hiking shirt, so it’s not necessarily harmful either. (I say “potential” because the styling I’ve seen on permethrin-treated knit shirts are a far cry from what I actually want — they fit into that “poor-fitting, slopping-looking base layer underwear” description.”)

  3. Todd on March 11, 2015 at 10:14 am

    Have you ever used a hemp shirt? I have a long sleeve hemp/cotton shirt that is super comfy and I thought might be good for hiking is warm weather when cotton doesn’t have to be avoided. I’ve read that hemp is quick drying and very durable (more like polyester) and naturally odor resistant (like wool), but haven’t had to field test these claims just yet. Also hemp production is very environmentally friendly.

    • Katherine on March 18, 2015 at 2:17 pm

      Todd- In my experience in another context (cloth diapering) hemp dries more slowly than cotton. Nor is it odor resistant! (whereas wool actually is)

  4. Mark on March 11, 2015 at 4:40 pm


    Any idea where to get a GoLite pack, besides eBay? Also, have you thought of designing your own line of backpacks?

    • Andrew Skurka on March 11, 2015 at 7:31 pm

      Why get a used GoLite pack online when you get a new pack that is at least as good. ULA Equipment also fills that niche of lightweight and durable packs. A suitable substitute for the GoLite Jam is the ULA CDT or ULA Ohm; for the GoLite Quest, the ULA Circuit or Catalyst.

  5. Andrew on March 11, 2015 at 7:36 pm

    On a thru-hike of the Superior Hiking Trail I also tried using a rain jacket as a bug shirt, far from ideal but relief from the flying hords. Have you tried a windshirt? I would think it would be more breathable while offering protection from bugs. Any thoughts or suggestions?

    • Andrew Skurka on March 11, 2015 at 7:45 pm

      Funny, two Andrew’s making the same mistake.

      A wind shirt would be better than a rain shell, but not as good as a woven shirt and not nearly as good as a knit top. Try breathing through the different fabrics — if there is any resistance, the fabric will most definitely trap some amount of heat and moisture, which is not what you want from your hiking shirt.

  6. Dave F on March 11, 2015 at 9:57 pm

    A little off topic since you’re talking about shirts, but I’ve had good results using permethrin for ticks as well. I hike in Chacos and thin wool socks, which ticks have an easier time latching onto than shoes. I remember picking at least 30 off of me throughout a day in Shenandoah Nat Park a few summers ago… treated the socks with permethrin when I got home and hiked the same trail the next weekend. Not a single tick to be plucked.

    • Andrew Skurka on March 12, 2015 at 6:29 am

      Living out West and only hiking back East in off-seasons, I kind of forget about the tick concern back there. Permethrin will definitely help with that. In fact, given that I had at least three people on my trips in Shen (15 people total on two 3-day trips) contract Lyme, I would probably be applying permetrhin on everything I wore.

  7. Albert on March 12, 2015 at 1:00 pm

    I’m a big fan of the Ex Officio BugsAway Halo shirt. Not because the looks or comfort – nothing notable there. It is because of the factory permethrin treatment. It results in a 6-12″ bug free force field. It’s rather amazing. This shirt was battle tested on Skurka’s guided Alaska trip and it did an amazing job keeping the bugs away. In comparison, my pants had spray-on permethrin. There was no force field effect, rather the bugs would land on the pants then instantly fly off. After a few days the effectiveness of the spray-on treatment was largely diminished. I guess the lesson there is factory treatment is much more effective.

  8. Paul Osborn (@bcoutdoor) on March 12, 2015 at 3:54 pm

    Thanks for the recommendations on the Permethrin. I bought a bottle years ago, but haven’t used it on the kids’ clothes due to concerns. We bought Columbia Sportswear bugproof shirts for them instead and they seem to do the trick in the Pacific Northwest.

    I guess I’ll be spending some time at the Sierra Trading Post, checking out their Bugsaway options!

    Several of my close family have contracted Lyme and other tick related diseases. My nephew struggled with it for over 5 years.

    Thanks for the article!

  9. Craig on March 14, 2015 at 7:59 am

    Great thread Andrew. It’s worth checking out fishing shirts from companies like Orvis/Simms/Cabelas. The fishing world has been making bug/sun shirts for a long time.

  10. Heath on March 15, 2015 at 8:48 am

    Great post, thanks for the info. Just as a heads-up to all, permethrin can be toxic to cats so you want to be a little careful with it’s use and storage if you have cats in the house.

  11. Mike on March 21, 2015 at 4:27 pm

    I’m a fan of Rail Riders bug shirts and pants. They’ve held up really well through some heavy use.

  12. Jesse on April 30, 2015 at 10:54 pm

    Is there a currently available non-treated bug shirt you’d recommend for us paranoid folks who prefer to avoid permethrin?

    Is the best bet tightly woven nylon, and accepting that I’ll be hot and sweaty? Is there anything not too stuffy out there?

    • Andrew Skurka on May 5, 2015 at 10:00 am

      Do you have any evidence to support your “paraonia” about permethrin. According to our “mad scientist” at Sierra Designs, “In terms of balancing effectiveness/safety/durability, permethrin is in the sweet spot, at least compared to any competitive technologies.”

      If you want to avoid chemicals, the only alterantive option is to accept being hot and sweaty. The hotter and stuffier the better — if the fabric has high air-permeability, bugs can bite through it.

      • Jesse on May 11, 2015 at 3:43 pm

        Nope, no evidence at all, hence the term “paranoia” – just a personal preference for caution when it comes to wearing insecticides on my body, and the historical perspective that many chemicals long thought safe at low levels of exposure later turned out to have long-term health concerns, like BPA and many agricultural pesticides.

        We don’t know that permethrin is in this category, but without rigorous, large-sample size, long term prospective studies proving no risk to repeated permethrin exposure over decades, I’d rather be a little uncomfortable and keep pesticides off my body wherever possible. If such studies are out there, though, I’d love to know because it would sure make dealing with bugs easier!

        • Sam Weller on June 4, 2015 at 9:35 am

          I absolutely agree with the point about the unknown toxicity of many chemicals and the lack of long term studies. However the prevalence of tick borne disease (Lyme Borrelioisis and the many others) is thought to be under-reported and under-diagnosed. The long term consequences of these type of chronic multi system infections can be very serious and thought should be given to the risk/ benefit of potential permethrin toxicity in areas where exposure to ticks is likely.

    • Doug K on August 25, 2015 at 10:56 am

      not Andrew, but I have been using Columbia nylon long-sleeve shirts as bug shirts, and as basic hiking shirts when in buggy areas. Unbuttoning the front while hiking is usually enough to maintain some kind of comfort/breathability. Also have some cheap cotton/poly blend l/s shirts that work surprisingly well – with enough poly the shirt does not wet out like cotton, dries fast, and the blend is tough enough to stop mozzies.

  13. Daniel on July 21, 2015 at 2:03 pm

    What about bug pants? Are they necessary in heavily buggy areas, or do the treated shirts work well enough to repel insects across your entire body?

    • Andrew Skurka on July 21, 2015 at 2:53 pm

      Most pants, especially stretch woven nylon pants, are naturally insect-resistant or -proof because the fabric is too thick or too tight for insects to bite through. That said, my concern is normally flying insects, not ticks, and if I were dealing with the latter I would also insist that my pants be permethrin-treated.

  14. PS on March 23, 2016 at 7:04 am

    Anything new in 2016 that you might suggest for a bug shirt (either treated or not as I’ll do it myself if it doesn’t come that way) that would be good for high heat and humidity and heavy exertion environments?

    I’ll be off to central Brazil at the end of July for a mission trip to build housing and am working on the “perfect kit” for a minimal pack. It’ll be up to the 90’s + during the day and bright sunshine and I’ll be shoveling dirt, hauling brick etc.


    • Andrew Skurka on March 23, 2016 at 8:57 am

      In those conditions, I would stay away from tightly woven shirts with little air permeability. Instead, go with a treated knit.

      My current favorite knit is the Sierra Designs Long-Sleeve Pack Polo (long-term review). It is awesomely breathable, and it would make a killer shirt in those conditions with a DIY treatment or with a treatment applied by InsectShield, the latter of which will probably be more durable.

  15. Kurt Suttell on October 9, 2018 at 4:25 pm

    Hi Andrew, Thanks for all the info your providing with this website. I have three questions for you about bug shirts. Touching on the wind shirt used as a bug shirt, I have a Houdini that I love and It would be nice to know if i need a bug shirt in a pinch it would do the job. If I’m already carrying a wind shirt how would it perform for preventing bites? I understand that a wind shirt will not be as breathable as a knit shirt. Next question is the color of bug shirts. I have heard that light colors help repel mosquitos. I don’t know how true this is, but i figured light color would be good for helping stay cooler in the daylight sun. Do you find the light colors help with the mosquitos? Last question, collars on a bug shirt Yes or No? I have a long-sleeved shirt i like that i could treat, but it dosen’t have a collar. Thanks

    • Andrew Skurka on October 9, 2018 at 4:49 pm

      A windshirt will usually keep the bugs off you, but it’s not recommended for everyday use, because they’re even stuffier than a nylon “safari” shirt and they’re not nearly as comfortable next-to-skin.

      I’ve hears that neutral colors help, but can’t say for sure. Intuitively, it makes sense: don’t make them think that you might be food or have nectar.

      A big yes on collars for bug shirts. A collar is the only way to get a good seal with a headnet, and the collar will help keep bugs off your neck.

  16. Cory on April 6, 2019 at 11:14 am

    Any thoughts about mesh bug shirts over a long-sleeve nylon safari shirt? I tried permethrin clothing (two different brands), and it would appear that I’m in the small percentage that react to it (burning, watery eyes, runny nose, vertigo and headache after an hour….gone in 30 minutes after changing shirts). I’m planning a trip to the Amazon jungle. Thank you!

    • Andrew Skurka on April 8, 2019 at 9:12 am

      Sounds hot, and not very durable.

      I’ve never heard from anyone who reacts poorly to permethrin, good to know.

      • Cory on April 8, 2019 at 10:03 am

        Thank you. I hadn’t thought about durability. I’ll have to have a backup set and/or plan. I may try permethrin again to make sure, but it’s happened twice (LLBean pants & shirt, Toad & Co shirt).

  17. James Johnston on July 28, 2019 at 4:11 pm

    I think here’s another option for your readers – polyester shirts directly from Insect Shield, e.g.

    I couldn’t really find any reviews about these shirts on e.g. BPL or r/Ultralight, but thought I’d try it anyway given the price vs the ExOfficio shirts. My wife & I just completed a 3+ week trip on the JMT with these shirts, and while they might not be quite as comfortable as the light Patagonia Capilene light-weight quarter zips on your gear list, any such complaints stop as soon as the mosquitoes start flying: we passed through countless mosquito-infested lakes and meadows, and never got bit as long as we were wearing our permethrin clothing. We never even touched our bug repellent spray, and would probably leave it at home next time. (Our favorite event: passing by Johnston Meadow/Lake in the evening – our namesake – and finding it to be the most infested location of the whole trip. And didn’t get bit there.)

    Also worth calling out might be that you can get Insect Shield Buffs & headnets (Sea-to-Summit). We found the Buffs offered adequate protection in less-infested areas without the annoyance of a full headnet: it still eliminates a lot of surface area (neck, ears). And there was something terribly pleasing about watching mosquitoes die in the folds of the headnet. Well worth the extra $1 or $2.

    I’ve been telling everyone last couple days on the JMT 2019 FB page to dress in this Insect Shield / permethrin stuff head-to-toe when people ask about what to do about insects…. this stuff works and hardly anyone out there seems to know about it!!! (or worse, offers bad advice like use DEET) — thanks for including this rather critical section in your book / blog! 🙂

  18. Randy Cain on November 28, 2021 at 9:53 pm

    I’ve never figured it out, but if skeeters can’t bite through a nylon shirt to begin with, why would anyone need Permethrin on it? I’ve used Railriders shirts for years that come “supposedly” treated with Permethrin, yet skeeters by the masses walk around on the shirt like there’s nothing even there. And no, they don’t fall over dead either. 🤷‍♂️ The Permethrin either doesn’t work or is long worn off. But they can’t bite through the material regardless. So every year in the Sierra, I get covered by plague-level mosquitoes and just have to get used to seeing them land on me…knowing that the material itself is protecting me. So what am I missing here? I’ve been backpacking for the past 10 years in the Sierra and rely on nothing but tightly woven fabrics and a head net, and I rarely get bitten. What extra benefit would Permethrin give me?

    • Andrew Skurka on November 29, 2021 at 7:34 am

      A physical defense is one good option for keeping the mosquitoes off you. But it has a downside, in the form of a very stuffy fabric, because the fabric can’t be a woman’s so tight to keep mosquitoes out while also letting much air and moisture through.

      The chief benefit of permethrin is that a highly breathable knit polyester fabric can be used. I have had multiple clients in Alaska use this type of garment, and the results are shockingly good.

  19. Randy Cain on December 15, 2021 at 2:49 am

    Yep. So regarding the fabrics in your first paragraph, those don’t need Permethrin. It’s like putting Permethrin on a wind shirt. I don’t understand the obsession with that. Railriders and others selling treated clothing that’s already bug-proof seems gimmicky. The breathable stuff in your second paragraph makes complete sense though.

    • Andrew Skurka on December 15, 2021 at 9:00 am

      It’s slightly better than the marketing of a shirt as having SPF. There’s absolutely nothing special about such the fabric — the SPF is inherent to the knit or weave, not some type of technology. The only thing exceptional about the garment is that was SPF tested, without which it can’t be marketed as having SPF.

  20. Brad Austin on January 26, 2022 at 2:05 pm

    Hey Andrew, love all the info on your blog! Just curious if you have any updated recommendations for good bug shirts now that is it 2022? Has much changed in the past 6+ years since this was written?

    I’m in Utah and hope to do a lot of hiking/backpacking in the Uinta Mountains this summer. The bugs can get pretty gnarly in July… and rather than avoiding going there during peak bug time, I need to improve my clothing/gear.

    Would love to hear any of your thoughts/recommendations? Thanks!

    • Andrew Skurka on January 26, 2022 at 6:27 pm

      What I’ve seen work best is sending your favorite knit polyester hoody to Insect Shield for treatment. It’s the best of both worlds: very breathable and quick drying fabric, a hood for sun and insect protection, and the permethrin to keep all the insects off you.

      The factory-level treatment is far superior to the DIY options, so do this right.

  21. Paul on March 26, 2023 at 10:02 am

    I hiked the Colorado Trail with a lightweight hoodie. I combined it with a baeeball cap for sun protection and it kept the bugs away. For my legs it was just a base layer for my legs and shorts on bug days.
    I did use some deet on any remaining exposed skin when the bugs were bad.

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