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Brynje Wool Thermo Mesh “Fishnet” Base Layers Review

Wool Mesh Base Layers

Baselayer tops and bottoms are supposed to transport perspiration from your skin into your midlayer clothing so that you stay drier and warmer when you’re working hard in cold weather. That’s the theory behind layering. But how many times have you pulled off your fleece sweater, only to find that it’s dry and your base layer top is soaking wet? Happens a lot with modern wool and synthetic base layers.

Brynje Wool Mesh Thermo Long Underwear

Odor Control
Ease of Care

Warm and Wicking

Brynje Wool Mesh Thermo Long Underwear has an open mesh-style weave which traps warm air under a mid-layer. Perspiration is very efficiently wicked from your skin to your next layer, keeping you drier and more comfortable. This is especially useful for start and stop snow sports where effective moisture management is a top priority.

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Brynje of Norway, pronounced “Brin-ya,” is a Norwegian company that makes mesh base layers that look a whole lot like fishnet underwear. The spaces in the mesh trap warm air when worn under a mid-layer, just like other base layers. But the mesh, which is available in wool or synthetic propylene, doesn’t hold onto to your perspiration because there’s so much less fabric to absorb it. Instead, it gets passed along to your mid-layer garment, keeping your skin warm and dry, while making your mid-layer garment noticeably damp. It’s a very noticeable effect.

Brynje’s Wool Thermo tops and bottoms take a little reprogramming to get used to if you’ve been bred on merino wool base layers. First off, they’re very form-fitting, although they stretch out a bit once you paint them on (figuratively speaking.) Solid panels in the mesh help increase the durability of high wear areas, such as the knees and shoulders (underneath backpack straps.) The long johns pictured above don’t provide much “support,” so I wear fitted Under Armour boxer under them. I imagine that women may want to wear a sports bra under the tops as well.

I’ve worn the wool tops and wool bottoms on numerous hikes and fat biking rides in cold weather and it’s astonishing to me how much warmer and drier I feel without needing to wear additional insulation layers. Be advised that you may need to rethink your existing “layering stack,” because you will feel warmer with Brynje baselayers and not need as much outer insulation as you did previously.

If you try these baselayers, my advice is to start with a Brynje top, since its easier to adjust or vent outdoors than the bottoms. I’ve found that wearing a mid-weight layer over the mesh works better than a very thin layer because it can absorb more perspiration, but your mileage may vary.

The only real gotcha with these Brynje base layers is clothing care. It’s very old school. You’ll want to hand wash the wool thermo top and bottoms in cold water with a very gentle detergent like Woolite and then hang them up to dry. Whatever you do, don’t put them into the drier. The shrinkage is extreme. You’ll never be able to paint them on again. The good news is that the Brynje Wool Thermo base layers don’t stink up nearly as quickly as solid Merino wool base layers, so you can wear them longer between washes.

High recommended, especially if you run cold in winter.

Disclosure: Brynje provided the author with baselayer garments for this review. But hey, we’re impressed. They’re really great!

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  1. An old idea re-imagined. Mesh tops (I don’t remember bottoms) were what we wore under our old school itchy wool shirts for winter backpacking forty five years ago. However, being ancient times the material was, unfortunately, cotton. Merino and polyester as performance fabrics were still in the distant future. These miracle fabrics make winter so much more comfortable.

  2. Love mine, I been using Brynje ‘fish Net’ for over 30 years. Great for hiking and cross country skiing. Warm , lite weight and if you wat to cool down in a hurry, just vent them. You do get some odd comments when suiting up at the hostel. They work.

  3. For winter, these are great.
    Unfortunately, these are a second piece of gear you would wear in warm weather. They do not stop or repel bugs. You still need that “solid” covering over your skin. So, they are very specific to cold weather, ie <40F. For spring, fall and summer, they fail by holding an insulating layer of air next to you.

    • I wear the short sleeve top under a long sleeve light hiking shirt in the summer (high desert 100+ at times). Simply unbutton the shirt to provide venting. The mesh keeps the wet off my back and the long sleeve shirt provides sun protection.

      • That’s good advice, Jeffrey, I might try that too. I can’t stand the feel of my closely woven nylon shirts against my skin and my usual base layers are too hot.

        Pro-cyclists use mesh base layers in summer too – in 100+ degree heat; there must be something in it.

  4. A few years ago, there was a link on BPL to a reseller who was going out of business and had these short sleeve mesh tops (some by Brynje, some unbranded)but in polypropylene, for $5. I picked up a couple and have worn them winter backpacking, and agree that they work great at keeping you warm and dry.

  5. I spent a winter with the Norwegian army a long time ago and fishnet undergarments were standard issue equipment. I’ve still got mine 32 years later and it still works great!

  6. Philip, do you think we would need traditional zip neck type to “expel” the extra heat (is there any extra?!) or normal crew neck is enough? Would you use this with something like Rab Alpha Flash Jacket for stop&go ativities (skiing) or that’d be to drafty?
    What about backpacking in colder condition? Woolnet + windshirt should be enough (+ thin fleece for rain in the backpack) I’m think about this type of garment for long time, but not sure..
    Love your articles! Big fan! Thank you!!!
    Ps. Living in rainy country

    • Layering is on of those areas where you really have to experiment, a lot, to see what works for you.
      I’m not familiar with the Rab alpha, but if it uses Polartec alpha, well, I wasn’t impressed with its breathability last year on a Montane jacket.
      My guidance is to keep your layers very simple and limited to one function – wicking, warmth, wind protection or rain, heavy insulation regardless of the season.
      For example, I often wear a baselayer and wind shirt, as you suggest, or wicking, warmth, wind.

      • The trick with Rab Alpha Flash Jacket is that it’s “open” so no extra wind resistent material with this fluffy fleece. That’s why there have to be windshirt or HS.
        I was wondering that it might to open/drafty setup with woolnet instead of normal wool baselayer. I just dont like wet back all the time.
        I know your & Skurka principles about layering. This look like wicking/warm/winshirt-HS to me, propably gonna have to try..
        Thanks for sharing the know-how!

    • Woolnet + Rab Alpha Flash under hardshell jacket I mean ;P or windshirt

  7. I use Coghlan’s mosquito pants and a NOVARA cycling baselayer that is nylon mesh …a cheapo version of this, but works very well.

  8. Been using the tops, both merino and tactel ones for several years. They are astonishingly efficient and warm.
    Best not to use them as a top layer on their own though. Get funny looks and comments.
    Trust me…..

  9. I’m stoked that Brynje is getting some attention, because I absolutely LOVE mine!!! I backpack almost exclusively in the High Sierra and have a full set (top and bottom) in my kit year around.

    I just now realized that is in business out of Boise, ID. I had previously bought all of my stuff from, because it wasn’t available in the U.S. Nordic Life is a great company to deal with, but obviously it will take longer for stuff to arrive.

    • I’m pretty sure neither of those websites are “byrne”. They’re just web retailers. You can also find some Bryne on Amazon, that’s actually listed by the company.

      • Yeh, they’re web retailers, but you can get more selection there. Looking at Amazon, the selection seems extremely limited. For instance I can’t find any of the bottoms at all, no caps, etc. Just seems to have tops. Nordic Life, for instance, has a ton of Brynje products, so that’s why I had always gone with them. Strangely, the one time I thought of buying a Brynje cap from Brynje of Norway, they were out of stock, but I found that Nordic Life had it.

  10. I have been using mesh tops and bottom from made in grand junction CO with great results

  11. $40.68 seems wicked expensive for a tee shirt, even if it is specialized gear. Does it really wick sweat that much better than regular smartwool or polypro?

    • I have now used a Brynje wool mesh top for three months. I’ve found it does little or nothing more than regular “wicking” fabrics to move sweat off my skin, even following Phillip’s use suggestions. Your mileage may vary, since I sweat far more than most people. (I’m not overweight, or out of shape, so it is fluke of my metabolism.) I also hike mostly in the humid East. Wetting through from sweat is a problem, however, in cold weather which could potentially become a threat. So, I carry extra base layers and change at mid-day. On the plus side, I can wash the Brynje shirt in the machine on delicates cycle, and it air-dries quickly with zero shrinkage.

    • Natick Labs ran tests on fishnet wool with many other fabrics over 10 years ago. Part of the conclusions:

      “When used as a base layer, there is no difference between fishnet and any of the other common knits relative to your core temperature. The only difference is in the perception of moisture on your skin surface…..all five base layer knits tested had the same breathable layer over them (BDU). They were tested using a wide MET range in cool weather. Although the testers perceived differences in the way they felt, core temperature instrumentation showed 0 difference for the five common base layer knit types (1 by 1 rib, fleece, fishnet, interlock, and double layer rib using polypropylene).”

  12. Much better. I’m newly converted! Totally a different paradigm.

  13. I’m going to give this a try. I was looking at the long-sleeve wool with shoulder inserts. For shipping to the US
    The Nordiclife site mentioned above saves $51 over the official Byrnje webite and $24 over the Brynjeusa site listed above. Selection on Amazon is pathetic. Looks like others figured that out too as they are out of several sizes, drat!

  14. You mention wearing a mid weight mid layer over your mesh rather than a light layer as they absorb more sweat…are you wearing a wool mid layer over your wool mesh or a synthetic mid layer over the wool mesh?


  15. I’ve been using the Wool Thermo Light shirt with a light, wool baselayer over it and my softshell cycling jacket for commutes when the temperatures are a little below freezing. None of the clammy effect that you get with other combinations, which can then turn ice cold while waiting at a long stoplight. Great stuff!

    Bought through the website, which had a much better selection in my size.

  16. Good stuff. I have been using it for a while. I like it with Buffalo pieces as my outer layer. Allows high exertion in cold weather and excellent moisture management. With this combo, the wool light is all I need with air temps down into teens and wicked wind. Buffalo is also excellent gear which should be considered.

  17. Is this really a winter-only type layer? Could you use them under a generic loose fitting long sleeve poly button up for moisture management in warm/hot weather? Do they function as a sleep layer, or do you need a close fitting “cap” (windshirt?) for the air pockets to be effective?

  18. I do a lot of short, fast hikes in the winter (live near the AT) and of course sweat like a pig on steep uphill sections, even when stripped down to just a base layer. I thought I’d give these a shot (poly version) to see if they would have better moisture management than my usual wool or silks. I wore it under a thin fleece and surprisingly, never felt so wet while hiking. It seemed like the sweat had nowhere to go and just clung to my skin. I finally peeled off the fleece and prayed that nobody was coming down the mountain to see me hiking in freezing temps in a fishnet shirt.

  19. Polypro versions of this concept are extensively used by cyclists in both cold and hot weather.

    I have a cycling top that I use for x-country skiing in Australia’s mild humid winters under a driclime wind shirt.

    I don’t quite understand the physics of how they work so well but they are very good at controlling soaking of mid layers which is a real problem for me as a heavy sweater and someone who likes to work hard when walking and skiing.

    This and grid fleece are now my go-to base layers but the mesh is superior as it literally cannot stay damp.

  20. Hi! Have you tried these for sleeping as well? I’m looking for a very lightweight sleep layer, if I could use these in summer as a sleep layer + in spring/autumn as a baselayer then it seems very good value.

    But I expect they don’t trap much warmth unless you have another layer directly over the top?

    • The purpose of these is less about trapping warmth and more about wicking perspiration. You probably want to avoid that in a sleeping bag because it will make the bag dirty.

    • Robert Traveller

      Hope I’m not too late.
      I own the Aclima version which have elbow and side inserts but otherwise very similar.
      Never used them for sleeping.
      I would guess they would work fairly well. Keep the sleeping bag fabric off your skin.
      Just went for a short walk, 34 deg F, a bit breezy.
      Wearing (not tight) jeans my legs were quite chilly,with the fishnet, comfortable.
      On top I was wearing fishnet, light wool woven shirt, 80 gsm puffy jacket.
      A bit chilly, the jacket is not terribly windproof.

  21. Bill in Roswell GA

    How do the Brynje sizes run compared to US sizes? Charts with numbers are one thing, actual human experience is what I’m looking for!

    If I wear a large top in Marmot and ArcTeryx, should I order a Large from Brynje? Or if I wear a medium in Patagonia or Columbia PFG button shirts, should I order a Medium Brynje?

    Bill in Roswell, GA

    • I recall that it was true to size.

    • Bought Super thermo Zip polo in Large–fits like a glove with good sleeve and torso length.

      Note: I am 6’1″, 150 lbs, with arm length a bit longer than normal and large was perfect. Good quality garment.

      The zip neck is twice the ‘usual’ height, something that was not completely obvious to me from website picture, perhaps because it may be folded over (maybe I should have noticed that…). Next time I’d probably buy the ‘crew neck’ style.

  22. I’ve long been a fan of fishnet as base layer for winter hiking, and have used multiple different generations over last 40 or so years. These ranged from wool, to early poly (Halley Hensen?) and some coolmax (mfg now forgotten, shirt gone). Nice to see new source of wool. For myself I most recently bought a couple of very reasonably priced short sleeve shirts off Amazon–get this:

    “Freebily Men’s Breathable Fishnet See Through Short Sleeve T-Shirt Tank Top Undershirt Clubwear ”


    Yup CLUBWEAR. See through, lol. Very fitted (of course!) so size up. Perfectly reasonable otherwise. Dries in a flash, keeps that wet back feeling away.

    I layer it under a lightweight poly long sleeve (e.g., Patagonia Capilene or terramar) then a Grid fleece hoodie (this one is a nicer Bauer product), or zip t-neck.

    Never used fish net bottoms.

    As an aside, since Alpha Flash was mentioned I have been experimenting with that as next layer over Hoodie, with or without a RAB wind jacket. (Note, to be clear the Alpha Flash is ONLY the Polartec Fabric, no shell/outer face cloth). Still an experiment in progress, but I’d say very light and warm, with option of ditching windshirt for super breathability. (I believe Phil you are not a wind shirt fan, but I find the jacket to be an extremely flexible and useful comfort and warmth item, especially for minimal weight).

    Tom Graefe

  23. Aclima Woolnet is an alternative. Just got it in, super comfortable. Already owned Brynje synthetic but the waistband was uncomfortable under a hipbelt. With what wool costs I did not want to risk being disappointed so I switched to Aclima. Glad I did.

  24. I had original Norse- Net in the 1970’s, both top and bottom and even though they were cotton they were better then anything else I had. I wore them hunting all the time. Can hardly wait to try the wool!

  25. I’ve been experimenting with this concept for several months using different base layers while out salmon fishing in cold water and weather.

    Those old-school thermal underwear that are white and super stretchy with wide gaps in the weave, they are actually quite effective at doing something similar to the fish-net style. Even though they are often around 50% cotton (synthetic blend) they breathe incredibly well. They also provide that nice air trapping trick when something is layered over them that makes them much warmer, yet still breathable. I find that these work pretty good for my legs when layering other stuff over them, and they are super cheap. It probably helps to get them small enough that they need to be stretched to put on. Probably not the most ideal, but they can be purchased anywhere and are cheap, and they hold up pretty well with use.

    I also tried my OR Echo sun shirt (mine is the hoodless version), which is about as lightweight as a shirt can get without being completely see-through. They breathe really well in all conditions. When paired with a shell jacket or fleece, it warms up a lot more than it seems like it should. The thumb holes in the long sleeves are also great for a base layer that extends all the way past the wrists. I think another HUGE benefit of the OR Echo is that on sunny days on the snow, when ripping layers off while going up a mountain, it’s also still just as critical to keeping the sun off your skin as it is in the summer. Too many people don’t think at all of how much they get sun damaged on snow, even in winter. I often strip down to base layers when stair stepping up steep/deep snow, even if it’s 10F outside and 40MPH winds.

  26. wore Brynje ‘fish Net’ in sub zero in the 70s when I snowshoed in the Eastern Seaboard
    before they invented the word merino

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