woman sitting on green truckbed in Kari Traa baselayers and beanie putting on pants and smiling
(Photo/Eric Phillips)

The Best Base Layers for Women in 2021-2022

Your layering system can be the determining factor between a bad day and a good day outdoors, whether hiking, skiing, or hunting. We’ve done the research — and testing — to find the best base layers of 2021-2022.

Base layers are an inevitability if you plan on recreating in any season that’s not summer. Whether you’re tackling a 14er in cool weather, hitting the slopes, or just going out to walk the dog on a frigid day, quality base layers can mean the difference between hypothermic feelings or comfortably navigating your day.

Our advice is to get the best base layers you can afford. Merino wool tends to be a top performer, but yak wool and a few other wool-synthetic blends can also be great performers in extra-cold environments. Compared to synthetics, wool has the bonus of holding warmth even when wet. It’s also the best for beating back scent for long periods of time.

But synthetic fabrics have a lot to offer. They’re often more affordable. And while you tend to give up some odor control, synthetics are the fastest-drying base layers. Fabric options like Patagonia’s well-regarded Capilene are a top choice for aerobic activities where you will work up a sweat thanks to their quick-drying properties.

If you want to learn more about base layers, jump down to the buyer’s guide and FAQ at the bottom of this article. Otherwise, read on for our top picks for the best base layers for women in 2021-2022.

The Best Base Layers for Women of 2021-2022

Best Overall Top: Smartwool Merino 250 Base Layer Crew Top — Straight & Plus Sizing

Smartwool Merino 250 Base Layer Crew Top

Smartwool is ubiquitous in the world of base layers, and this top is the top-selling base layer for women from REI’s site. You’ll find 100% merino in this best choice, and that’s just because it works so dang well. Women love both the fit and feel of this easy-going crew, and the fit is right on target. This is also a size-inclusive piece, as it’s available for plus-size women in 2X and 3X.

After weeks of wear, we can attest this base layer is a top performer. We especially love the softness and next-to-skin comfort of this base layer as well as the ease of layering.

The Smartwool Merino 250 ($100) keeps you warm but isn’t overly warm. We’ve worn dozens of midweight layers, and some of them border on too warm for average winter temps. The Smartwool 250 performs beautifully across temp ranges and is one of our go-to choices for higher-intensity winter activities like skiing.

What customers said: “Perfect fit, aesthetically pleasing. Soft and comfortable. Doesn’t itch. Soaks up sweat on hard hikes but washes out so no sweat stains leftover! Would absolutely purchase again and recommend.” — Schisticlees

  • Weight: 218 g
  • Fabric: 100% merino wool
  • Thermal Category: Heavyweight
  • Super soft
  • Comfortable cut
  • Crossover use outdoors and for professional meetings
  • Build feels strong
  • Does not fare well in washing machine
  • Some don’t like the slim fit

Check Straight-Size Price at REICheck Plus-Size Price at REI

Best Overall Bottoms: First Lite Kiln Long Jane

 First Lite Kiln Long Jane

Can we live in our First Lite Kiln Long Janes? The answer is yes, and we have. We’ve worn these feminine long johns for days on hunts, only to find that they stave off body odor better than any other we’ve tried, even after hours of hiking and packing.

They’re our favorite fit of any base layer we’ve owned. High-waisted, soft, and with seams in the right spot to avoid backpack misery — these leggings ($90-95) are made for women. And though First Lite is a hunting brand, it offers base layers in solids for those of you who might not need camouflage in your life.

Merino rules the day, and these are opaque enough to wear as a first layer on warmer days with no issues. With an 18.5-micron, 250g merino and spandex woven fabric, these are a true midweight pant. But in our humble opinion, they’ll get you through the great majority of cold situations with no problem. We’ve worn ours for a few years, and they feel practically new. Dreamy, you guys.

What customers said: “Outstanding leggings. True to fit. Minimal compression fit. Super comfortable. Soft to the touch. I am 5’5″ with an athletic build and weigh about 135 lbs. Medium is a perfect length and fit for me. Material is medium thickness and warm. Wicking and antimicrobial system is on point. I will buy these in every color.” — InspiredByNature

  • Weight: 227 g
  • Fabric: 95% merino wool, 5% spandex
  • Thermal Category: Midweight
  • Very fine, soft merino wool fibers
  • A match for -20 to 60 degrees F and humidity
  • Size large pants tend to slide down for some users

Check Price at AmazonCheck Price at First Lite

Best Overall Hoodie: First Lite Kiln Hoody

First Lite Kiln Hoody

Hoodies are either your jam or not. We like to wear hoodies when we know we want a second layer to keep our head warm beneath a hat or when the weather isn’t bad enough to require a shell hood.

When we need a midweight hoodie, we grab our First Lite Kiln Hoody ($115-125). We can repeat a lot of what we said about the Kiln bottoms. This thing just beats back odor, wicks and breathes like magic, and fits in a way that eliminates bulk.

Like the pants, if you caught us wearing our Kiln Hoody, you’d likely think it was a new purchase. Fewer washes beget longer use times. We’re into it. Another benefit to remember with paying more for wool is that, if you get wet, you still retain heat. Synthetics might dry faster, but the warmth merino offers is a real big plus.

What customers said: “In the winter I live in wool base layers since I work outside in cold conditions. I’ve owned merino base layers from all the top brands and I have to say I am very impressed and happy with the First Lite merino base layers I’ve bought. The material is excellent and the design is great. I love the long sleeves and thumb loops.” — Heather Krauss

  • Weight: 425 g
  • Fabric: 95% merino wool, 5% spandex
  • Thermal Category: Midweight
  • Excellent quality
  • Ideal versatile weight
  • Fit is snug and some opt to size up
  • Can feel tight around broader shoulders
  • Hood can be restrictive when pulled up and looking around

Check Price at AmazonCheck Price at First Lite

Best Budget Set: PISIQI Thermal Underwear Set

PISIQI Thermal Underwear Set

As a broke college student, we couldn’t afford high-tech gear, so we turned to a cheap base layer set ($20-24) to get us through ski season. And it performed the job for years. So in honor of those times, we sought out the top-reviewed thermal underwear on Amazon Prime. With over 1,700 reviews and a 4.6-star rating, this PISIQI set is a very affordable and well-loved performer.

Don’t expect uber-durability, but if base layers are something you need a few times a year, this looks to be a great option with an even better price tag. Made of ultra-soft polyester, these are purported to be forgiving with a second-skin feel.

What customers said: “I went to Alaska, everyone made fun of me for buying these saying I wouldn’t need them. Joke is on them, Glacier Bay while sailing is chilly in early May. I got my money’s worth from these as an underlay. They were soft, comfortable, fit as expected, and work beautifully with layers. Hands down, buy them.” — Tiffany

  • Weight: 281 g
  • Fabric: 92% polyester, 8% spandex
  • Thermal Category: Lightweight
  • Wicks moisture well
  • Fabric provides a 4-way stretch
  • Economic choice
  • Not enough thermal protection for sedentary winter activities like ice fishing

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Best Budget Top: Patagonia Capilene Midweight Crew

Patagonia Capilene Midweight Crew

It almost feels odd to put a Patagonia piece as a budget pick, but the Capilene Midweight Crew ($59-69) is an affordable gem that will last a very long time. Offered in a variety of colors and patterns, you’ll likely find one that will fit your vibe.

We will say Patagonia’s Capilene isn’t quite as odor-forgiving as merino, but it still holds up well and fits well too. And the wicking properties are exceptional. Capilene dries quickly, and Patagonia’s move to include recycled content in its clothes makes this a feel-good option for the sustainable-minded.

What customers said: “I bought this for a hiking trip and never wanted to take it off! The shirt is a comfortable material, great and flattering fit (not too snug but not too big), lightweight, and easily layered. I really like the thumb loops at the ends of the sleeves to keep the shirt from moving when layering.” — Elizabeth B.

  • Weight: 153 g
  • Fabric: 100% polyester
  • Thermal Category: Midweight
  • Antimicrobial treatment helps squash body odor
  • Thumbholes included
  • Polyester is 50-100% recycled
  • Merino wool works better to shield body odor, in our experience
  • For some, the fit was big and boxy

Check Price at REI
Check Price at evo

Best Budget Bottom: REI Co-op Midweight Base Layer Tights

REI Co-op Midweight Base Layer Tights

For only $50, you can own one of the most-loved base layers out there. The REI Co-op Midweight Base Layer Tights have a 4.75-star rating, a few patterns to choose from, and a ton of fans. The polyester-spandex fabric ensures wicking properties and comfort, and women love the high-rise feature of these pants.

These pants (which also come in a top and set) are a great option for those who camp in every season, and they’re durable to boot. We’ve worn these for full weeks at a time doing trail maintenance and heavy hiking, and they worked out great. They’re super easy to slip on and off and are a great layer option for those who might run cold and want reassuring warmth at night when the temp drops.

What customers said: “I wear them with a sweater on dreary days, I wear them on the slopes, I wear them as I tuck into a sleeping bag at night. All-around comfort and fits perfect.” — Concrete

  • Weight: 190 g
  • Fabric: 92% polyester, 8% spandex
  • Thermal Category: Midweight
  • UPF 50+ rating to protect against harmful rays
  • Quick-drying
  • Fabric bleeds — hand wash to start

Check Price at REI

The Best Gifts Under $100
The Best Gifts Under $100

We found the best outdoor gifts under $100. From an ultralight hammock to a legendary puffy, this gift guide has it all. Read more…

Best Plus-Size Bottoms: REI Co-op Lightweight Base Layer

REI Co-op Lightweight Base Layer

We were pleasantly surprised to see REI has plenty of offerings for base layers for plus-size women, between Smartwool and the REI Co-op brand. And the affordability and positive reviews on these bottoms ($40) make them a shoo-in for gals who’ve often felt left out of the world of athletic clothing.

This is a lighter base layer but will get you through a ton, with a fitted poly-spandex mix. If you want to level up and go merino, check out Smartwool’s $100 offering of its 250-weight legging.

What customers said: “I’m a plus-size gal with hips, and it’s always hard to know if sizing will work for me or not. This material is wonderful and seems like it would be able to accommodate a large range of shapes. I got these (the tights as well as the tops) to sleep in, and I’m just super impressed. Totally comfy, love the material, and even though they’re lightweight, I stay plenty warm.” — Jiffle

  • Weight: 208 g
  • Fabric: 100% merino wool
  • Thermal Category: Heavyweight
  • Super soft against skin
  • Hems are not too tight
  • Merino wool wears down faster than wool-synthetic blends

Check Price at REI

Best Softness: Le Bent Le Base 200 Lightweight Crew

Le Bent Le Base 200 Lightweight Crew

This could be the lightest, softest, stretchiest, most attractive base layer top we’ve ever worn. We want to use it for everything outside and inside, even going out to dinner. We wore the Le Bent Le Base 200 Lightweight Crew ($85) nonstop for several days of outdoor activity in the Colorado Rockies including frigid, windy trail runs, wintry walks, and even sleeping.

The shirt’s buttery blend features bamboo rayon, merino wool, elastane, and four-way stretch. The arms and torso are long, so no skin is exposed in extreme temperatures or wind chill. And the fabric masked odor for multiple days despite sweaty activity. This is the perfect do-it-all layering piece during and post sport.

What customers said: “This is a great base layer that is very versatile. These base layers are great even for working women under their business attire. In the northern states it can be cold walking to your office and even once there, many work environments are chilly. This layer is lightweight, warm, and thermal-regulating, but never itchy. It is a great addition to a work wardrobe as well as for the slopes. I bought a second one!” — Dolores

  • Weight: 200 g
  • Fabric: 66.5% rayon from bamboo, 28.5% merino wool, 5% elastane
  • Thermal Category: Lightweight
  • Extremely soft
  • Versatile contoured fit for the ski slopes, town, or meetings
  • UV 50+ protection
  • Not a heavyweight choice for stagnant winter moments like glassing for your elk hunt

Check Price at Amazon

Best Heavyweight Top: Duckworth Powder High Neck Top

Duckworth Powder High Neck Top

Reviews tout the cloud-like feel of this sweater-like base layer ($165), made of merino wool fleece. Eliminating the need for a gaiter, the turtleneck adds functional fashion. With a front pocket and a few classic colors to choose from, this piece can be worn casually or in action on the slopes.

The high price tag begets the fact Duckworth’s clothes are made in the U.S. from sheep raised and sheared in Montana. There’s a true farm-to-fit story behind the brand’s clothes. And man, do they last. We beat up a pair of Duckworth base layers for 6 years on the regular before they bit the dust.

What customers said: “I now have three of these sweaters, one reserved for work and two for home and hiking. They are so cozy and comfortable, they can handle sweat without smelling, and they are nice enough to wear out to my favorite brewery!” — Cara

  • Weight: 454 g
  • Fabric: 50% merino wool, 30% acrylic, 20% polyester
  • Thermal Category: Heavyweight
  • Key pullover for ice fishing or hunting trips
  • Generous fit that’s cozy
  • Brushed fabric is soft against skin
  • High neck offers protection and warmth
  • Very oversized for some users

Check Price at Duckworth

Best Heavyweight Bottoms: Sitka Gear Heavyweight Bottoms

Sitka Gear Heavyweight Bottoms

Another hunting brand makes it on the list. Unfortunately, these bottoms aren’t offered in solids. But they’re awesome. And we’ve had trouble finding a decent pair of legitimately heavyweight base layers for the coldest times until these hit our kit.

For most of us in most climates, midweight layers will do the trick. But if you’re seeking out the warmest base layers possible, consider the Sitka Gear Heavyweight Bottoms ($99).

These are made of a heavyweight fleece with a sweatpants-like feel. The rise is a little lower on the hips, but for the most part, these pants stay put. This polyester-elastane blend also does a pretty good job combating odor using Polygiene technology. And when the weather gets cold (and skiing or hunting isn’t on the docket), you can find us drinking coffee in these in our apartment or wearing them under bibs for winter errands.

  • Weight: 215 g
  • Fabric: 93% polyester, 7% elastane
  • Thermal Category: Heavyweight
  • Very warm
  • Comfortable fit
  • Seams are streamlined
  • Workhorse construction
  • We wish that the backside fabric reached higher

Check Price at AmazonCheck Price at Sitka Gear

Best Half-Zip Base Layer: Kari Traa Rose Half-Zip

womens kari traa rose sale

Merino continues to dominate, and the Kari Traa half-zip brings a classic ski lodge feel to the list. Offered only in fashionable Nordic patterns, this 100% merino half-zip ($110) has a feminine touch with an athletic makeup. Developed by an Olympic skier, Kari Traa’s base layers also have amazing design features like underarm gussets and a more athletic fit around the shoulders and hips.

One of our editors was really impressed after testing out the Rose Half-Zip. It performs super well doing laps on the slope, and the zipper never jabs or digs into your skin (just make sure you get the right size). During spring skiing and late-winter seasons, you can also feel great shedding your hardshell and retaining warmth with this layer. And you’ll look great, too.

What customers said: “I love my merino kari traa huddy — the material is really pleasant to wear — soft, but most of all [works] and protects in bad weather. It’s easy to wear with pride as it looks gorgeous.” — Alexandra S. 

  • Weight: 240 g
  • Fabric: 100% merino wool
  • Thermal Category: Midweight
  • Extremely warm
  • Quality construction
  • Merino wool blends wear down quicker than synthetic-wool
  • Not the stretchiest fit
  • Feels a smidge itchy for some sensitive users

Check Price at REICheck Price at evo

Best Wool Blend: Black Diamond Solution 150 Merino Base Crew

black diamond solution 150

Black Diamond uses a wonderful merino wool blend called Nuyarn in its Solution 150 Merino Base Crew ($135), and multiple members of our testing crew love the material.

Nuyarn gives users the best of both worlds, with the odor resistance and soft hand of merino combined with the durability and quick-drying nature of polyester. It’s a simple design of this fabulous fabric, featuring just thumb holes to keep the layer in place on the arms when pulling over second layers.

What customers said: “The fabric is comfortable, moves with you, soft, and the advertised sizing is accurate … I also used multiple days in a row and the stink was to a minimum — the wool did its job at ensuring the person next to me smelled worse!” — SAR Alexis

  • Weight: 146 g
  • Fabric: 78% merino wool, 22% polyester
  • Thermal Category: Lightweight
  • Non-bulky fit
  • Breathable blend
  • Fine, stretchy 18.5-micron merino wool
  • Thumbholes
  • We wish the length was more generous

Check Price at Black DiamondCheck Price at Amazon

Best of the Rest

Kora Shola 230 Crew

kora Shola 230 Crew

Kora base layers are made out of yak wool, and this stuff performs. It’s pricey at $130, but only a bit more pricey than merino, and it tends to be warmer for less weight. In our experience, that’s a bit of a toss-up unless the weather is really cold. We tend to use our Kora layers as heavyweights rather than midweights, as they’re just a bit too warm for early to mid-fall for what we’re up to.

This crew is a constant in our winter kit. It’s thin enough to easily go under sweaters or fleeces for added warmth, and it’s nice enough to wear on its own with a vest on warmer days. Yak wool really does pack a warm punch. If you’re doing legit stuff in cold weather, invest in Kora.

  • Weight: 240 g
  • Fabric: 60% yak wool, 40% merino wool
  • Thermal Category: Midweight
  • High-rub areas feature reinforced thread for durability
  • High-quality construction
  • We appreciate the lengthy arms
  • A bit pricier

Check Price at Kora

icebreaker 250 Vertex Leggings

icebreaker 250 Vertex Leggings

The Vertex leggings by icebreaker ($130) are made for movement, and women love these leggings for a myriad of reasons. Once again, made of merino, these are certified by the Responsible Wool Standard, upping the expense but setting welfare issues at ease.

Reviews state these are soft and lack the itch of previous products. They are only offered in print, but it’s an après-ski-friendly kind of print.

What customers said: “I am always cold in winter so have been on the hunt for comfy pants that are also warm. These are the best I’ve found, so I have bought them in both colors! I’m also super sensitive to itch and these are even less itchy than other Icebreaker products I have.” — CIWaldron

  • Weight: 250 g
  • Fabric: 100% merino wool
  • Thermal Category: Midweight
  • Gusset is well-designed for range of motion and comfort
  • Soft against hand
  • Comfortable
  • Fit a bit loose, especially in waist and knee area
  • We’d prefer these to sit a bit higher above the hips

Check Price at REICheck Price at evo

REI Co-op Lightweight Base Layer Top — Straight & Plus Sizing

REI Co-op Lightweight Base Layer Top

A runner-up for the budget pick, this top is available in straight and plus sizing, from XS-3X. And gals of all sizes really do love this shirt. We love that pricing ($40) doesn’t change from one garment to another. Nice work, REI.

A soft poly-spandex blend makes this piece comfortable and wicking to wear. It’s a nice enough shirt that you can wear it on its own in public or under a fleece on a mountain outing.

What customers said: “I bought two of these tops to use as a base layer, but I wore one just as a regular top to hike 2.5 miles on a cool humid day with the temperatures in the mid-50’s. Although I kept up a fast pace on my hike, I never felt sweaty and the top quickly wicked away any sweat while keeping me warm enough to not need a jacket. Thanks so much REI for offering technical clothing in women’s plus sizes!” — TGirl

  • Weight: 167 g
  • Fabric: 92% polyester, 8% spandex
  • Thermal Category: Lightweight
  • Offers UPF 50+ sun protection
  • Wicks sweat well
  • Feels itchy for some users
  • Snug around bust area for larger-chested ladies

Check Straight-Size Pricing at REI Check Plus-Size Pricing at REI

Voormi Women’s Base Layer Bottoms 

Voormi Women's Baselayer Bottoms 

Voormi’s thermal base layer bottom ($119) is one of our top choices for backcountry skiing and splitboarding, resort skiing and riding, post-adventure après, and year-round camping. We’ve taken multiple hut trips packing only this base layer bottom in a range of climates and conditions from gripping-cold blizzards to sunshine.

Despite back-to-back usage, the pants don’t reveal odor, and beads of water roll right off the top surface. Our sweat and any water patches dry fast, so we never feel damp or clammy in these long johns.

The fabric — a fine micron-wool construction with against-skin wicking yarns that pull and disperse moisture to the outer layer — is very soft, extremely durable, and lightweight for the density and warmth provided. The material and seams hold up through arduous usage beneath snow pants and jeans in all seasons.

What customers said: “These base layers are very warm, wick well, and are breathable. I am a snow shoe person, and snow shoeing can range from high output to slow going and this base layer adjusts well. Would recommend” — Jason

  • Weight: 195 g
  • Fabric: 52% merino wool, 48% polyester
  • Thermal Category: Midweight
  • Super durable
  • Shields water and sweat extremely well
  • Athletic fit prevents chafe without feeling too tight
  • An investment

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Janji Swift Tech Mockneck LS 

Janji Swift Tech Mockneck LS 

Whether we’re skiing pow or jogging groomed trails, the Janji Swift Tech Mockneck LS ($66) is a nice addition to our base layer lineup that keeps us cozy without stifling body heat. The silhouette feels good to pull on with the lengthy arms and ergonomic seams that even fit our pole-planting shoulders well.

The fit is pretty snug without feeling restrictive, and the lower half doesn’t fit tight against the abs, preventing the shirt from sliding up. The material wicks sweat well (and pit stains are pretty visible, FYI) and dries quickly. We love the slightly higher neckline, which isn’t a full-on turtle neck but adds a bit more protection right where a biting wind can take your breath away.

Our one drawback is, when we have stinky sweat, the fabric doesn’t do much to mask the stink. But if you don’t mind or don’t stink, this cut is unique, attractive, and functional with great crossover into everyday use before or after getting outside.

What customers said: “This is the perfect base layer you can wear alone. I wore this top for a 100-mile bikepacking trip in Big Bend. The temps ranged from 35-70. It was perfect alone, under a vest, or under a cycling jersey. It’s PERFECT. Also, it’s suuuper soft. The fit is so sleek!” — Vanessa

  • Weight: 162 g
  • Fabric: 84% polyester, 11% merino wool, 5% spandex
  • Thermal Category: Lightweight
  • Integrated thumb holes are seamless and comfortable and provide upper hand warmth
  • Construction is free of harmful chemicals
  • With only 11% merino wool, B.O. is typically noticeable

Check Price at Janji

Helly Hansen HH Lifa Crew Performance Base Layer

Helly Hansen HH Lifa Crew Performance Base Layer

One of the longest-standing base shirts we pull on for high-cardio snow sports is the Helly Hansen Crew Performance long-sleeve top. And at only $45, that price tag is hard to beat for the decade-reaching quality without a single unraveled seam.

This extremely lightweight and breathable design doesn’t make us feel claustrophobic on a bell-to-bell powder mission or ringing mogul after mogul. The pull-on smoothly wicks sweat and doesn’t hold onto the moisture. The seams never rub or annoy our skin, even on the more sensitive folks.

The fit is not too snug, either, but if you prefer an even looser fit, check out the men’s cut instead.

What customers said: “I am very happy with my purchase. This shirt is a great base layer — wicks sweat so I feel more comfortable. It’s form-fitted enough to not be wrinkly under other layers, but not so fitted that it feels tight. I’m not a fan of crewnecks, but this one is cut low enough that it doesn’t feel like it’s choking me. It is also well-constructed — should hold up to the test of time. I bought it for trekking with a pack, but will definitely also use it for sailing and cruising.” — Ellen

  • Weight: 107 g
  • Fabric: 100% polypropylene (Lifa)
  • Thermal Category: Lightweight
  • Nice option for high-output activities
  • No itchiness
  • Great wool-free choice
  • Not extremely insulated for low-movement activity
  • No thumbholes

Check Price at AmazonCheck Price at Helly Hansen

Arc’teryx Motus AR Crew

Arc'teryx Motus AR Crew

Once the temps drop, we grab this just-right base layer for trail runs or uphilling at the ski area. The Arc’teryx Motus AR Crew ($79) pulls our sweat and dries like a champ. The exterior fabric is treated with a DWR finish to barricade dew and drizzles, so we can skip a midlayer if it’s warm enough out and not pounding snow.

We like the mini turtleneck style, which offers a boost of protection for our décolletage and blocks drafts. The shirt is designed for ultimate freedom of movement, so side-to-side motion or planting poles doesn’t feel held back. And the seams don’t feel bulky, either.

What customers said: “If you’re a fan of the existing Moths hoody, this new crew won’t disappoint. The same light, super-comfy material, and the same flattering slim-but-not-too-tight fit. I always prefer non-hooded versions as they layer better and are more versatile, so this crew is perfect for me. Love it. Am getting all three of the current colours and will look forward to more colours in future seasons!” — K9K8

  • Weight: 125 g
  • Fabric: 100% polyester
  • Thermal Category: Lightweight
  • Soft against skin
  • No itchiness
  • Not extremely durable for alpine and rock climbing according to some users

Check Price at Backcountry

Buyer’s Guide: How to Choose the Best Base Layers

Start by imagining how you’ll use these base layers. Are you looking for something extra warm for relaxing around camp? Or will you be working hard in the backcountry and need a breathable, fast-wicking layer? There’s no right or wrong answer, but knowing how you’ll use these layers will help narrow the field.

Styles of Base Layers

Technically, base layers feature a range of designs including tank, long-sleeve, and short-sleeve tops, as well as ankle-length or capri pants. In our guide, we focus on the best options for cold weather and the winter season, which are usually long-sleeve tops and ankle-length bottoms.

The fabric blends of base layers include merino wool, synthetic fibers, or a blend of the two. Within those fibers, there are various densities from lightweight to midweight or heavyweight. Some tops feature a hood, partial zipper, or thumbholes. Others are tailored with a crew, mock, or turtleneck.

Base layers are absent of pockets or belt loops. These designs are meant to be worn against the skin in a seamless way that’s comfortable beneath other midlayers and outer layers across various activities such as hunting to fishing, hiking, skiing and snowboarding, snowmobiling, or working on a farm.

Fabric Blend

Merino Wool

We love wool. It regulates temperature really well. It’s fast-drying, comfortable against the skin, and resists odors like a champ. It’s the warmest fabric choice for low-intensity outdoor activities like ice fishing or spectating ice skating.

That said, 100% merino wool tends to be less durable, gets wear holes more quickly, and gets baggy throughout the day. If you have sensitive skin, even the smoothest 100% merino wool might feel a tad less than cloud-like next to skin. Depending on your preference, you may prefer a wool blend or straight synthetic materials.

Merino wool can also cost more than its counterparts.


An alternative to wool is a synthetic fabric, which is typically a blend that includes polyester plus elastane or spandex for rebound and form. Some synthetic fabrics are proprietary to a brand with treatments that enhance odor-fighting ability and wicking moisture.

Synthetic blends do not offer as much warmth and overall temperature regulation that wool provides. They’re a great choice for high-intensity activities that produce a lot of perspiration without long moments of standstill, like during a hunt, when a chill could set in.

These fibers can work really well for people with sensitive skin, especially for exercise use. The breathability is still excellent and really only a hair less impressive than merino wool or wool-synthetic blends. Also, synthetics typically cost less than wool.

One drawback: Odor-intense days are not typically covered up well by this fiber.

Wool-Synthetic Blend

Many folks find a fair balance of managing heat and chill, absorbing sweat, and covering up odors in a design that weaves together both wool and synthetic fibers. Adding synthetics also enhances the durability and overall life of wool apparel.

Insulation Weight


If you’re running hardpack snow trails, snowshoeing, skate skiing, or doing uphill ski workouts in 30-degree temps, a lightweight base ayer top or bottom should do the trick, as long as there’s no wind chill. Lightweight layers dump heat really well. These could be a good piece for warmer spring laps at the ski resort, but sitting idle on lift rides typically calls for a warmer midweight base layer.


Not too airy and not too stuffy, the midweight base layer is optimal for wintry days skiing and riding at the resort. It’s a good choice for snowmobiling, when pulling the throttle can pack windchill at high speeds. That said, for intense heat-building activities like huge ski or splitboard tours or snowshoeing, a midweight layer might be too much.

woman reading book and holding mug in base layers
(Photo/Xander Bianchi)


When we’re talking extreme temperatures — well below zero or even below freezing — then you might be coziest in a heavy-set base layer, especially for ski resort laps. These are also the layers we grab for sedentary periods. Those activities include ice fishing, sailing, hunting, spectating events, hanging at base camp during a mountaineering expedition, or even snowmobiling groomed trails, especially if sightseeing stops are frequent.


Insulation & Warmth

This ties into end use. For extra-cold weather or more sedentary activities like ice fishing, sitting in the hunting blind, or relaxing around camp, you’ll want something warmer and with more insulation power. The strongest options will be in that heavyweight label.

If you’re using your base layer for major cardio output, opt for a lightweight design.


In addition to trapping heat, it’s important the layer breathes well and efficiently wicks moisture. Freezing sweat will make you colder faster than a too-thin layer. Generally, the lighter a design is, the more breathable it will be. Merino wool is also more breathable than synthetics.

The Smartwool Merino 250 is a warm winter layer that breathes incredibly well. It’s our top pick for the dead of winter but also for alpine pursuits in fall and winter.

If you know you’re going to be busting it uphill on a bluebird day, then look for a lighter layer. Something like the REI Co-op Lightweight Base Layer Top will be a key part of your layering system.

Odor Prevention

If you’re packing minimally for multiday use, like a hut-to-hut or mountaineering trip, merino wool does wonders with hiding odors. Generally, synthetic materials don’t champion covering up stench as well as this natural fiber.

Comfort & Fit

There’s nothing more annoying than ill-fitting base layers. From backside or frontside sagging to pulling to chafing, it’s important to find comfortable-fitting long underwear. Things to consider are softness against skin and tightness. You want a base layer to fit snugly against your body while allowing full range of movement.

It’s also important to look at length and seams. You don’t want gapping at the waist. Nor is it ideal to have too-short sleeves or pants. Seams can cause chafing, so beware of your movement and potential trouble spots. If chafing is a constant problem, you may want to consider the seamless Patagonia Capilene base layers.


Thermal layers are an investment, so it makes sense you want them to last. Synthetic layers are often more durable but can cause more trouble with retaining odors. Merino wool is naturally odor-fighting but tends to be more fragile. You’ll want to take care putting them on and use them mostly as true base layers underneath protective pants or other layers.


How Should You Wear Base Layers?

Base layers — as their name implies — are meant to be worn as the base of your clothing system, next to your skin. If you pile on cotton underwear and a cotton T-shirt under your base layers, you’re negating all the ways a base layer is intended to work. Most base layer bottoms are intended to be worn as long underwear.

Should a Base Layer Fit Tight or Loose?

A base layer should have a close fit to your body without sacrificing freedom of movement. Some base layers are tight-ish, but not restrictive or circulation-ending, while others are a tad roomier but not bulky. Base layers should be able to fit nicely beneath a fleece sweater as well as a pair of Carhartt pants or overalls or ski outerwear.

man and woman gearing up for the snow
(Photo/Xander Bianchi)

How Do You Choose the Right Fabric for Your Base Layers?

Really, it comes down to what you can afford and what activities you do. Synthetics are highly durable, high-wicking, and have some odor-beating technology. Synthetics usually have a lower price tag.

Merino is less durable, but it has temperature-regulating features that can work in a wide range of weather, combats odors, and also wicks well. Merino wool typically costs more than synthetic blends. You might notice we left silk off this list. Silk needs a lot of washing, is very thin, and is not very durable. Most of the base layers on this list are a wool blend or polyester-elastane blend.

The weight of the fabric you choose is also important. Most people will do well with a pair of simple midweight base layers. If you’re perpetually cold or doing a sedentary winter activity, grab a pair of heavyweight base layers. If you’re buying base layers to backcountry ski, run in, or for any other intense activity, go light. Easy peasy.

What Is a Good Base Layer for Cold Weather?

If you’re handling extremely cold temperatures, have poor circulation, or tend to be cold-sensitive, grab a heavyweight set like the Smartwool Merino 250 Base Layer Crew Top, Duckworth Powder High Neck Top, or Sitka Gear Heavyweight Bottoms.

For all-around recreation and use in average winter temperatures, grab a midweight option like the First Lite Kiln Long Jane and First Lite Kiln Hoody. Then, cardio intense activities, like running or cross-country skiing, and warmer winter days are a good time to opt for lightweight base layers like the PISIQI Thermal Underwear Set.

What Is the Best Layering System for Winter Activities?

For the greatest warmth and protection, you’ll want to wear full underwear and a sports bra followed by base layers, which wick sweat and help manage body heat during high output or laidback activities. Base layers fit beneath a midlayer — like a fleece or micro-down jacket or synthetic insulation layer — followed by an outer layer, like a shell, that strongly protects against the elements from rain to snow or wind.

Depending on the day’s activity and climate, you might prefer to wear a base layer beneath an outer layer and skip that middle piece of insulation.

What Kind of Bra Should You Layer Beneath a Base Layer?

Of course, for us gals, bras are often a necessity. So don’t make the mistake of wearing a nonwicking bra beneath your base layers. Find yourself a sports bra that fits, wicks, and supports to combat sweat and chills on your upper half. Then let any of these base layers work their magic!

skier putting on Smartwool socks and ski boots
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