The best base layers of 2020 are made of high-quality fabrics with technology to keep you warm and dry. These are some of our favorite men’s shirts for winter sports in wool, synthetic, and blends.
There are a lot of great choices for long underwear these days. To help you pick the best this season, GearJunkie reviewed and has itemized a list by price and insulation category. Here’s the topic breakdown:
- Ultralight base layers
- Lightweight base layers
- Midweight base layers
- Heavyweight (insulating) base layers
- Tips to buy base layers for others as gifts
When possible, we’ve also identified the country of origin and provided fabric weight in either grams per square meter (g/m²) or microns.
Best Baselayers of 2020
One tip before we dive in: Everyone has an internal thermostat. If you tend to run cold, buy warmer. If you find yourself stripping off layers when others are bundled, go lighter.
Part 1: Ultralight Base Layers
Superlight and form-fitting, the ultralight base layer will prevent heat loss on an autumn day, shun solar radiation when things heat up, or provide that first quick-drying layer against the skin under heavier base layers.
If you want to strip them off altogether, they disappear nicely in a daypack. The downside of the ultralight lineup is that they can be fragile. Materials like silk and thinly woven mesh can snag on brush and Velcro tabs.
Fabric weight: 80-135 g/m²
Wool fiber diameter (in microns): 17.5
Best Ultralight Top: Bjorn Daehlie Training L/S ($75)
Bjorn Daehlie is one of the world’s most decorated winter athletes, with 29 World Cup and Olympic medals in nordic skiing to his name. Daehlie hung up the skinny skis, but it’s no surprise his Training L/S long-sleeve takes the gold as our ultralight base layer pick.
The 60-40/merino-poly blend composes a simple crew that’s super-soft to the touch, wicks well, and stays surprisingly cool when charging the hills. The shirt is ideal for running in the mid-40s, but we were amazed to find how comfortable it was well into the 60s.
The core body panels have a flat, durable weave while airy mesh panels sewn under the arms spill more heat. The underarm mesh’s delicate weave is prone to snags, so be careful when stuffing it in a pack.
If we were to have one ultralight base layer for active winter pursuits, it would be this wool base layer top.
Fabric weight: 120 g/m²
Materials: 60% merino, 40% polyester
Made in: China
Best Bargain: L.L.Bean Lightweight Crew Base ($35)
Yes, it says “lightweight,” but its 130g/m² fabric slips just under the line to make our ultralight list.
The thin synthetic fabric layers well without any awkward binding or seam rub. In fact, we found all of L.L.Bean’s base layer lineup a great fit and recommend them for folks on a budget or anyone who simply wants a great-fitting shirt.
Fabric weight: 130 g/m²
Materials: 100% polyester
Made in: El Salvador
Rab Forge ($50)
Rab’s no-frills poly-wool-blend crew is a stalwart in our closets. It has an athletic fit with mechanical stretch that’s both durable and layers well with other garments.
We’ve tested Rab’s line of merino like crazy and still reach for it as a favorite for running, hiking, mountaineering, skiing, or any other activity where moisture-wicking and stink-inhibition are priorities. This is one of our favorite shirts, and it’s been going strong for 4 years.
Fabric weight: 125 g/m²
Materials: 53% polyester, 47% merino
Made in: China
Part 2: Lightweight Base Layers
Wear it alone in 30-degree temps or pair it with another layer when the mercury dips, a lightweight base layer is your skin’s first line of defense against Old Man Winter. During the colder months, we never leave home without one.
Fabric weight: 145-200 g/m²
Wool fiber diameter (in microns): 17.5-18.5
Best Lightweight Base: Patagonia Capilene Midweight ($59)
It’s the little things with Patagonia’s simple crew that elevates it to our top award in the lightweight base category. The smooth external face slides easily under another layer. On the inside, a diamond grid pattern adds a little stretch and micro pockets to trap heat and wick moisture away.
Two elastic thumb loops keep the sleeves down when overlaying a heavier base without adding a lot of extra material around the wrist. And when you’re done for the day, hang it at the lodge from the cord sewn into the back. The material is treated to keep the backcountry stink from chasing your crew back out into the cold.
Capilene is available in a variety of weights and is an excellent option across the board. It’s also incredibly durable. One of our editors has used a single Capilene shirt for nearly 30 years, and it’s still going strong.
Materials: 100% recycled polyester
Made in: Sri Lanka
Best Bargain: EMS Techwick Lightweight Crew ($25 on Sale)
With UPF 50-plus protection, elastic wrists, thumbholes, and Polygiene-treated material, Eastern Mountain Sport’s Techwick ticks all the boxes for a great lightweight layer.
The smooth-faced jersey is made from recycled materials and has a little stretch in the weave. It’s also half the price of the competition, so it gives you a little stretch in the wallet too.
Fabric weight: 160 g/m²
Materials: 100% polyester
Made in: China
Wool-polyester blends are becoming more and more popular. Leveraging the best of both worlds, they’re warm, manage sweat, and dry quickly.
Black Diamond’s Solution uses NuYarn material, spinning ultrafine merino wool around a synthetic core. We found that the materials dry quickly (a reputed five times faster than pure merino fabric, which can hold up to 30% of its weight in moisture), has fantastic mechanical stretch, and hits it out of the park for durability.
While it does contain wool, this baselayer feels great against the skin in part due to the flatlock seams. We’ve worn it for dozens of days and have been repeatedly impressed with this layer for comfort, quick-drying, and odor resistance.
The sleeves are long, with a true pair of thumb loops that wrap around the wrist. Just shy of $120, you pay the price, but this is an exceptional piece for hardworking backcountry enthusiasts.
Fabric weight: 150 g/m²
Materials: 78% merino wool, 22% polyester
Made in: Vietnam
Porous fabric panels line the back and gusset under the arms to spill heat where you sweat most. A touch of elastane keeps the Ghee moving with the body.
We found the shirt has an athletic fit but can feel big. That’s largely because the sleeves have proper thumb loops to wrap around the wrist without adding bulk or pull at the thumb. The shirt also has a long hem that tucks into your pants, eliminating those colds spots from creeping up the backside.
Fabric Weight: 170 g/m²
Materials: 85% polyester, 15% elastane
Made in: Vietnam
Many of the fabric blends on our list have roughly a 50/50 poly-to-wool ratio. For those who are partial to more synthetic than wool (and along with it, the fast-drying properties of synthetic), OR’s Enigma is a great shirt for the backcountry. And made mostly from recycled materials, you can also feel good about wearing it.
The Enigma feels super-soft to the touch, and we liked the clever offset patterns OR used on the sleeve. And the brand gave some special attention to the design of the thumb loops, which fold into the wrists’ hems. We’ve been using this shirt a lot this winter and really like how fast it dries when sweating it out in the cold.
The Enigma has a snug, athletic fit that cuts close up around the armpits. If you have broad shoulders, you’ll want to try before you buy. But if the shirt fits, the Enigma is a great shirt with a little flair for your backcountry fun.
Fabric Weight: 155 g/m²
Materials: 88% recycled polyester, 12% wool
Made in: China
Mission Workshop’s Advanced Projects Crew fits like a superhero uniform and reputedly elevates your performance like one too.
The garments use 37.5 technology — volcanic particles activated by humidity regulate the body’s optimal temperature during performance or rest. It sounds like the stuff from science fiction, but all you need to know is it feels cool when working out and warm when chilling out.
The elastic crew is the closest to a compression top and stays put around the waist with sticky tabs. The seamless construction reduces friction points. Superhero cape not included.
Fabric weight: 190 g/m²
Materials: 60% nylon with 37.5, 30% polypropylene, 7% nylon, 3% elastane
Made in: Portugal
Part 3: Midweight Base Layers
Cooler temperatures require a boost to your base layer. Midweight layers strike a balance between insulation and wicking power and are the workhorses of cold-weather pursuits that have you on the stop-and-go.
Wear these base layers for cold days or layer them over a lighter base for added versatility for changing weather conditions.
Fabric weight: 200-250 g/m²
Wool fiber diameter (in microns): 21.0
Best Midweight Base: Fjällräven Bergtagen Woolmesh Sweater ($160)
The Northwest Passage, Greenland, the South Pole — the Scandinavians wrote the book on Arctic performance. Their secret? Don’t let sweat defeat you. Their unofficial piece of outdoor gear? The string vest. It’s not pretty, mostly air, and looks like a fishnet, but it efficiently traps heat while letting moisture pass right through it to the second layer.
Fast forward a century, and Swedish outdoor brand (and GearJunkie favorite) Fjällräven has taken a page from the Arctic explorer’s handbook with its Bergtagen Woolmesh Sweater. The sweater uses uniquely knitted materials inspired by the original Arctic explorers to adapt to the body’s variable thermoregulation needs.
A porous wool-poly blend mesh overlays regions that need to spill heat. Plush, wool terry panels overlay the shoulders and torso. The intelligent panel construction regulates heat much more efficiently than traditional base layers, enabling this techie sweater to comfortably spread its wings across winter and into spring-like conditions.
The sleeves and collar are made of a wool-poly rib that shuns water and functions like gaskets to help trap heat. People with wider necks may find the neck too snug, though.
Fabric: Wool-poly-blend mesh, wool-poly-blend terry, wool-poly-blend rib
Made in: Estonia
Best Bargain: Eddie Bauer Midweight FreeDry Merino Hybrid Baselayer 1/4-Zip ($54 on Sale)
Eddie Bauer is a West Coast staple. The brand’s First Ascent line is its core mountain lineup.
If you’re wool-curious and don’t want to drop $100 on a base layer, the Heavyweight FreeDry merino is half off right now and is a helluva deal at $54. It has a more athletic fit than EB’s standard line and is sewn together with durable, flat-locked stitches, so it can take a beating in the hills. Get ’em while they last.
Fabric Weight: 230 g/m²
Materials: 50% merino wool, 50% polyester
Made in: China
Jottnar isn’t well known in the U.S. (yet), but it has a solid following in Europe. The British company makes high-quality kits for discerning alpinists and skiers. Its merino Heimdall is luxuriously soft and reminded us of slipping into a cashmere sweater.
But it was the synthetic Erling that caught our attention. It has a fantastic athletic fit with thumb loops and a drop tail that layers well both under and over, moving unrestricted with the body.
The weave is light and airy with a micro file-pattern loft on the inside that quickly wicks moisture to the surface while trapping warmth. If things get too hot, the front has a generous 1/2 zip to spill out heat.
The Erling is available in a hoodie, but we suggest you stick with the 1/2 zip. We found the scuba hood closes too tight around the face for us, blocking peripheral vision.
Fabric Weight: 220 g/m²
Materials: 100% polyester
icebreaker Oasis 200 ($58 on Sale)
Icebreaker’s Merino Oasis 200 is a versatile base layer that is exceptionally easy on the eyes. The no-itch, lamby-soft merino is comfortable against the skin and wearable up into the 60s.
The brand placed all seams strategically out of the way. But we wish they were all flatlocked (a few plain seams run down the sides and inside the arms).
The sleeves are longer and don’t have thumb loops, but this all allows flex without any pull. Our testers received several compliments on the shirt’s looks. For merino virgins, it’s a great investment to start a love affair with wool, and it’s on sale now for as low as $58.
Fabric weight: 200 g/m²
Materials: 100% merino wool
Smartwool Intraknit 200 ($120)
We’ve seen a lot of industries leveraging 3D technology to get an edge. And it makes a lot of sense in the garment world. Manufactured engineering seamlessly tailors fit with durable construction and artistic freedom, all the while providing a reduction of material waste.
Smartwool spent the better part of 10 years collecting the necessary components that could pull it off — workflow, machinery, and partners. It was a big hill to climb, but it was worth the wait.
Smartwool’s Intraknit is intelligently designed around the body’s natural efficiencies, weaving durability in high-wear locations with flexibility over articulating joints. Plush terry loops insulate regions that get cold while thinner-knit panels are woven over heat-spilling regions of the body to dissipate heat. The results strike a balance of warmth and breathability. On top of all this, and it also just looks good.
The most technical base in the batch, we got a preview of the Intraknit last spring and have been wearing the 200 and 250 for skiing, hiking, and running. It looks so great that it’s occasionally been worn around the office. The terry loops are a little delicate, so be mindful of taking it deep into the backcountry.
Fabric weight: 200 g/m²
Materials: 53% wool, 45% polyester, 2% elastane
Made in: India
Helly Hansen has a storied history with the cold. The brand’s latest iterations use thermal mapping to match the base layer materials with the body’s need to control its core temperature with precision.
We found the H1 Pro keeps you warm where you need it without leaving you feeling overheated. That’s partly due to the deep half-zip in front and the fantastic hood. But it’s not lost on the material differences found on the torso and back. Loose-knit panels are sewn over the belly and down the back to spill heat where the body sweats the most.
The arms are longer, with adequate length for the thumb loops that are handy for layering or keeping the wrists warm. And the drop tail tucks into your pants without creeping up. The fit is looser than many base layers on the list.
Materials: 100% merino panels; lined with Pro Lifa
Part 4: Heavyweight Base Layers
If your activities find you ice fishing, ice climbing, or bunkering down in a snow cave at 5,000 m, an expedition-worthy heavyweight is what you’re looking for. The heavyweight isn’t used alone; it supplements a light or midweight base layer.
Fabric weight: 300 g/m² and heavier
Wool diameter (in microns): 24.5
Best Heavyweight Base: Patagonia Capilene Air Hoody ($149)
Patagonia’s Capilene Air can be a misunderstood piece. Crazy-light (under 7oz) and super-airy yet super-warm, the Capilene Air flips the traditional base layer scale on its head and is often slotted as a midweight. This is in part due to the wispy 18.5-micron yarn.
Patagonia takes the merino-synthetic blend and air-blasts the yarn to loft the fiber. The result traps air while reducing weight (think of it like a downy feather). The entire piece is woven together using 3D knit to reduce waste and dial in a great fit.
The few seams that exist attach the sleeves to the torso through a broad, thin, flat stitch that virtually disappears. The snorkel hood is one of the best we tried and drops around the neck like a mock turtleneck. If hoods aren’t your thing, the Capilene Air is offered in a crew-neck version.
It’s not cheap and can snag while bushwhacking, but the trade-off is a garment that works fantastic over a wide range of activities and temperatures.
We gave the Capilene Air our Gear of the Year award in 2015. One of our reviewers wore it for an entire winter in the Boundary Waters. Purely because of its massive temperature range, we’ve selected the hoodie as our best pick for a heavyweight base. You get a lot of bang for the buck.
Fabric weight: 18.5-micron-gauge lofted wool
Materials: 51% merino wool, 49% recycled polyester
Made in: Hong Kong
Best Bargain: Cabela’s E.C.W.C.S. Heavyweight 1/4-Zip Top ($70)
Cabela’s can always be trusted to provide a trail-worthy product at a reasonable price. Its Heavyweight zip is a smooth-faced base with a relaxed fit and is designed for waiting patiently in cold temps.
Two thumbholes make pulling over another layer easy and are long enough to be comfortable when glassing the hills for game. The synthetic insulation is treated with Polygiene to reduce scent or scaring off your hunting partners.
Fabric weight: 255 g/m²
Materials: 93% polyester, 7% elastane
WoolX Glacier 400 ($120)
New York-based WoolX is making a splash in the niche base layer market — and for good reason. The brand’s merino is durable, super-soft, fits great, and is offered at a fair price.
At the tippy-top of the heavyweight base layers sits the Glacier 400. For such a heavyweight fiber, the glacier feels extremely comfortable — it’s got that T-shirt quality that drapes smoothly against the skin and begs to be worn.
Long cuffs with thumb loops seal around the wrists to keep the cold out on the coldest of days. The cut is a little more generous than other layers, but this allows it to layer over a lighter-weight base.
Is 400 not heavy enough for you? Then we introduce you to the Denali, WoolX’s 440 über-heavyweight merino sweater.
Fabric weight: 400 g/m²
Materials: 100% Australian merino wool
Voormi High-E Hoodie ($229)
Harvesting wool from high-altitude sheep in the Rocky Mountains, Colorado-based Voormi is a relatively new player. The company’s High-E Hoodie is the flagship of the brand and is constructed from a “dual surface thermal wool” with a DWR-treated synthetic outer fabric.
You’ll want to layer under this rugged sweater, but it’s soft enough that you don’t have to. It’s also tough enough to wear as an outer layer on warmer winter days. We’ve used this shirt for many outings and are blown away with its versatility and durability.
The High-E was one of our tester’s favorites for front- and back-country excursions.
Fabric weight: 310 g/m²
Made in: America from U.S.-sourced wool
Airblaster Merino Ninja Suit ($200)
If you find the mercury plummeting as fast as a Haines cornice, it’s worth checking out this one-piece. A proprietary blend of merino wool, Tencel, and spandex composes the super-warm and breathable foundation of this modern union suit.
The one-piece all but eliminates cold spots, cocooning the body in warmth with a high collar and form-fitting hood. The deep front zip provides a proper point of entry, and a 350-degree waist zipper yields immediate relief.
The one-piece suit is as warm as it gets while still being classified as a base layer.
Buyer’s Guide: How to Choose a Base Layer
Everyone who plays outside in winter needs base layers, and it’s hard to have too many.
When purchasing a base layer (for yourself or a loved one), consider the activities the person pursues.
High-aerobic activities (like running, ice climbing, and cross-country skiing) require fast moisture-wicking capability, where lightweight base layers typically shine.
For those who spend long days outside in more leisurely activities (like downhill skiing), a midweight base in merino wool or synthetic materials will serve you well and can be the most flexible piece in your cold-weather arsenal.
Merino vs. Synthetic
Merino can suck up to 30% of its weight in moisture. This isn’t a bad thing — that water traps heat and keeps you feeling warm. Synthetics hold less than 7% of their weight in sweat and can feel colder as moisture rapidly evaporates.
On the flipside, polyester fibers can trap stinky bacterial waste, which creates that funk that’s hard to wash out.
For mountaineers (or those who never change their clothes), do yourself a favor and get a stink-resistant merino or find a brand that includes stink-inhibitors like Polygiene.
This year, we’re seeing lots of options that leverage synthetic-wool blends with panels of lighter-weight materials. These feel super-soft and increase the temperature range of the layer.
Cut and Length
Most of these base layers are offered in crewneck, quarter-zip, and even with hoods.
To crew or not to crew is a personal preference. Some crewnecks can bind around the neck (which is uncomfortable when sucking air on hill sprints).
And it’s easier to cool off by dropping the zipper on those days where the sun comes and goes. But we did find ourselves inconspicuously sliding the crewnecks into our work wardrobe. It simply looks less sporty than the zipper tops.
Hoods and Thumb Loops
Hoodies are a fickle fit. Some hit it out of the park, and others squeeze awkwardly around the face, limiting your peripheral view. We called out hoodies that fit us well, but we highly recommend you try before you buy any base layer with a hood.
Many of the base layers on the list come with thumb loops. These can block the intense sun and warm the wrists (our vasculature tends to run shallow in the armpits, elbows, and wrists, close under the skin to dump heat).
They can also help keep the sleeves down when pulling on another layer. Like the hoodie, these can be run the spectrum on effectiveness. We’ve called out the real winners in our opinions and faulted them where they don’t quite measure up.
Have a favorite base layer we missed? Let us know in the comments for future updates to this article.