Reviews You Can Rely On

The 6 Best Base Layers for Women of 2024

We put women's base layers to the test from Ridge Merino, Smartwool, Black Diamond, Icebreaker, Patagonia, Carhartt, Mons Royale and more to find the warmest and most versatile options
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Best Base Layer for Women of 2024
Credit: Steve Mace
Wednesday February 14, 2024

We've purchased and tested dozens of the best women's base layers since 2015, and our current review features 17 of the most innovative options on the market today. We tested these tops side-by-side, in all kinds of conditions, across the globe. From sailing the high seas to scaling thousand-foot cliffs, skiing in the high mountains to running ultra-distance miles, down to more casual hangs around the campfire, we put these layers through their paces. Our team assesses each product across key performance factors like comfort, warmth, and breathability. Our field and in-house tests provide insight into the nuanced differences in these layers, and our test team provides expert advice to help you find the perfect base layer for your needs and budget.

If you're looking for more upper body layering options, we've tested the best women's fleece jackets, coziest down jackets, and both casual and technical softshells. We've also got your bottoms covered if you're on the hunt for long underwear. And if all this technical layering is new to you, check out our helpful article on how to layer clothing for each season and how to layer in general.

Editor's Note: We revised our women's base layer review on February 14, 2024, to remove two discontinued products from our lineup and to update the alternate recommendations in our award section.

Related: Best Base Layer for Men

Top 17 Product Ratings

Displaying 1 - 5 of 17
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Awards Editors' Choice Award Editors' Choice Award  Top Pick Award Best Buy Award 
Price $150 List$130 List
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$145 List
$145.00 at Amazon
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Overall Score Sort Icon
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76
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Pros Excellent thermoregulation, versatile warmth, Merino wool is cozy next to skin, durable polyester exteriorSoft and stretchy fabric, excellent fit, versatile warmth, quality construction, quick drying, fantastic stand alone layer, hole in hood to reduce bulkBreathable, excellent thermoregulation, extra warmth with hood, easy to layerGreat thermoregulation, exceptional wicking capability, very durable, easy to layer, excellent fit, super softAffordable, thumb loops, long cut, easy to layer over top, soft and durable fabric
Cons Expensive, open grid pattern difficult to layerPricey, no thumb loops or stash pockets, fabric smells over timeExpensive, takes a few washes to increase next-to-skin comfortExpensive, limited warmth as stand alone piece, longer drying timeMaterial is not midweight
Bottom Line This versatile Merino wool-blended base layer prioritizes warmth and breathability within a flattering athletic designThis high quality synthetic design offers maximum warmth through versatile and thoughtful design features geared towards efficient cold weather performanceAn outstanding lightweight performer featuring exceptional thermoregulation and breathability with an innovative Merino wool technology that gets softer with every useA lightweight base layer that features supersoft Merino wool along with a thoughtful design and fitThis affordable base layer features ultra fine Merino wool fibers that are super comfortable next to your skin, effectively wick away moisture, and remain odor-free
Rating Categories Ridge Merino Convict Arc'teryx Rho Hoody... Black Diamond Solut... Icebreaker Merino 2... Ridge Merino Aspect...
Warmth (25%)
8.0
9.0
8.0
8.0
6.0
Breathability (20%)
9.0
6.0
8.0
7.0
8.0
Comfort and Fit (20%)
9.0
9.0
9.0
9.0
9.0
Durability (15%)
8.0
9.0
8.0
8.0
7.0
Drying Speed (10%)
8.0
8.0
8.0
6.0
8.0
Layering Ability (10%)
7.0
8.0
8.0
7.0
8.0
Specs Ridge Merino Convict Arc'teryx Rho Hoody... Black Diamond Solut... Icebreaker Merino 2... Ridge Merino Aspect...
Fabric Weight Midweight Lightweight Lightweight Lightweight Lightweight
Measured Weight 8.0 oz 7.0 oz 6.4 oz 6.3 oz 6.0 oz
Material 54% polyester, 38% Merino wool, 8% spandex Torrent 190: 84% polyester/16% elastane 78% Merino wool, 22% polyester 100% Merino wool 84% Merino wool, 16% nylon
Avaliable Cuts Hoody Hoody, zip neck, crew Crew, 1/4 zip neck/hoody Crew, 1/2 zip neck Crew, 1/4 zip
Odor Control Fabric Naturally odor resistant Polygiene treatment Naturally odor resistant Naturally odor resistant Naturally odor resistant
Thumb Loops Yes No Yes No Yes
UPF Sun Protection No No No No 50+
Length Long Medium Medium Medium Long
Fit Fitted but not tight, true to size Trim fit, true to size Runs small Fitted but not tight, true to size Slim
Accessory Pocket Yes No No No No
Flat-lock Seams Yes Yes Yes Yes Yes


Best Merino Wool Base Layer for Women


Ridge Merino Convict - Women's


83
OVERALL
SCORE
  • Warmth 8.0
  • Breathability 9.0
  • Comfort and Fit 9.0
  • Durability 8.0
  • Drying Speed 8.0
  • Layering Ability 7.0
Material: 54% Polyester, 38% Merino Wool, 8% Spandex | Thickness: Midweight
REASONS TO BUY
Merino wool interior combined with polyester shell
Excellent thermoregulation
Great wicking power
Flattering fit with chest pocket
REASONS TO AVOID
Expensive
Open grid pattern is more difficult to layer

Meet your new favorite base layer: the Ridge Merino Convict combines the strength, durability, and wicking performance of polyester with the excellent comfort and odor-resistant abilities of Merino wool. The fit is flattering and true to size, while the Polartec Power Wool interior feels cozy next to your skin. Thoughtful features include discreet thumb loops that are invisible on the sleeve unless pulled over your thumbs, a low profile hood that is easily worn below a helmet, and a stash pocket on the chest for easy access to essentials while on the move. We also appreciate the gusseted sleeves and the purposely removed shoulder seams that improve our range of motion and comfort when carrying a pack.

Our team put the durability of this layer to the test while climbing on sharp volcanic boulders and navigating low-elevation deserts full of sagebrush and Russian thistle. We're happy to report no issues with the design – if anything, we couldn't help but notice the reinforced flatlock seams and durability of the polyester face fabric. If there's one thing to complain about, it may be that the open grid design is a double-edged sword. On one hand, it allows air to permeate the layer for incredible thermoregulation. On the other, it is much bulkier than the fabric of other comparable tops, like the Patagonia Capilene Thermal Weight Zip-Neck. This is something to consider with the Convict if your outer layers tend to run small. That being said, we're confident that this well-designed base layer will become your go-to, no matter the adventure.

Read more: Ridge Merino Convict review

The Ridge Merino Convict kept us high and dry on late-season, alpine rock climbs.
Credit: Trish Matheny

Best Synthetic Base Layer for Women


Arc'teryx Rho Hoody - Women's


82
OVERALL
SCORE
  • Warmth 9.0
  • Breathability 6.0
  • Comfort and Fit 9.0
  • Durability 9.0
  • Drying Speed 8.0
  • Layering Ability 8.0
Material: 84% polyester, 16% elastane | Thickness: Midweight
REASONS TO BUY
Fleece-lined to keep you cozy and warm
Slim fitting design is easy to layer
Hood, neck warmer, and full-face balaclava for versatile warmth
Durable and well-crafted
REASONS TO AVOID
Lacks some breathability
Expensive
Holds more odor than Merino

We've tested versions of the Arc'teryx Rho Hoody over many years, and it still stands out as our go-to synthetic for all technical missions. The interior is fleece lined with wicking power that does a good job of moving moisture away from the skin. We love the fitted design that is stretchy and incredibly easy to layer, plus the neck warmer, hood, and full-face balaclava that offers versatile warmth and protection from the elements. The hood even has a small opening for a ponytail to reduce bulk. This is one of the most versatile base layer tops we've tested, performing well on ski tours in Colorado to mega rafting missions in the Grand Canyon. As is true with most synthetics, wear and tear is minimal, even after being put through the wringer. Tried, tested, and truly awesome.

To benefit from the increased levels of comfort and warmth due to the fleece lining on the interior of this base layer, you must sacrifice a certain amount of breathability. If you're seeking a top that better balances warmth and breathability, consider the similarly priced Black Diamond Solution 150 Merino Quarter Zip. For the Rho Hoody, we instead suggest using this drawback to your advantage by wearing this layer as a stand-alone piece during the change of season to create a barrier between your sensitive skin and those cold north winds. This layer is also more expensive than other synthetic options. However, given that it is one of the most time-tested pieces that we've had the opportunity to use, the value of performance you get out of it is definitely worth the investment. The Rho Hoody is best for someone seeking a synthetic layer that's durable and technical, and looks great to boot.

Read more: Arc'teryx Rho Hoody review

The Rho hoody is the perfect layer for early season spring trail runs.
Credit: Trish Matheny

Best Value for Merino


Ridge Merino Aspect Midweight - Women's


76
OVERALL
SCORE
  • Warmth 6.0
  • Breathability 8.0
  • Comfort and Fit 9.0
  • Durability 7.0
  • Drying Speed 8.0
  • Layering Ability 8.0
Material: 84% Merino wool, 16% nylon | Thickness: Lightweight
REASONS TO BUY
Long cut and thumb loops for added warmth
Super soft Merino
Easy to layer
Thumb loops
Incredible value
REASONS TO AVOID
Fabric is not actually midweight

The Ridge Merino Aspect Midweight is a high-performing Merino wool base layer whose features far exceed the modest price tag. Constructed with 84% Merino wool and 16% nylon, it is one of the softest base layers that we've tested, while the nylon increases both durability and structure. Naturally odor-free, this layer can be worn for weeks between washes, and the thoughtfully placed flatlock seams increase comfort and prevent chafing when shouldering a heavy backpack.

While we do not consider this a midweight as advertised – it is an exceptional lightweight garment that is easy to layer over the top of. If you need something a bit warmer, consider the similarly priced Patagonia Capilene Midweight Crew. The slim-fitting, versatile design of the Aspect effectively traps body heat when temperatures drop and dumps excess heat when you pick up the pace. While not the warmest layer that we've tested, this is a great choice for the base of your cold-weather layering system.

Read more: Ridge Merino Aspect Midweight review

We love the UPF 50+ certified sun protection offered by the thumb loops on the Ridge Merino Aspect, that also increase the ease of layering by holding the shirt in place when layering over top.
Credit: Trish Matheny

Best Synthetic Bang for Your Buck


REI Co-op Midweight Base Layer Crew - Women's


72
OVERALL
SCORE
  • Warmth 7.0
  • Breathability 6.0
  • Comfort and Fit 8.0
  • Durability 8.0
  • Drying Speed 7.0
  • Layering Ability 7.0
Material: 92% polyester, 8% spandex | Thickness: Midweight
REASONS TO BUY
Great fit
Soft and stretchy fabric
Durable construction
Thumb loops
Affordable
REASONS TO AVOID
Smelly
Tightly woven fabric doesn't breathe very well

The REI Co-op Midweight Base Layer Crew is a great choice for those seeking a highly functional synthetic base layer with an affordable price tag. This garment offers enough warmth for those in-between-season days and is available for a fraction of the cost of its top-performing synthetic competitors. It also has durable features such as flatlock seams and thumb loops that give us confidence this layer will be around for many seasons to come.

We were disappointed by the synthetic polyester blended fabric, as we noticed it retained odor almost immediately. If odor rention is really off-putting, consider investing in a Merino top like the Ridge Merino Aspect Midweight. While the fabric successfully wicked moisture and sweat away from our skin, this layer couldn't efficiently release moisture through the tightly woven fabric, so it took longer to dry. This sometimes would mean sacrificing precious warmth during colder temps, so we do not recommend this layer for high output activities nor for the depths of winter. Overall, our testers were happy with the slim-fitting, durable design that kept us warm during the shoulder seasons or as the base of our layering system for moderately cold weather adventures.

Read more: REI Co-op Midweight Base Layer Crew review

The smooth synthetic fabric and functional thumb loops enhance the REI Midweight Crew's layering ability.
Credit: Trish Matheny

Best Thermal Crew


Icebreaker Merino 200 Oasis Crewe - Women's


77
OVERALL
SCORE
  • Warmth 8.0
  • Breathability 7.0
  • Comfort and Fit 9.0
  • Durability 8.0
  • Drying Speed 6.0
  • Layering Ability 7.0
Material: 100% Merino wool | Thickness: Lightweight
REASONS TO BUY
Great thermoregulation
Easy to layer
No odor
Excellent fit and durability
100% Merino is super soft
REASONS TO AVOID
Pricey
Limited warmth as stand-alone piece
Longer drying time

The Icebreaker Merino 200 Oasis Crewe quickly stood out from the competition thanks to its superior fit and super soft 100% Merino wool design. Ultrafine 18.9-micron fibers are tightly woven together to create a layer that successfully traps heat and wicks moisture away from the body. Our testers love the thoughtful design that includes strategically placed flatlock seams that increase comfort and durability and gusseted underarms to allow for better mobility.

Perhaps our biggest complaint about this crew is the limited breathability when layered in a system. The Oasis can wick sweat away from the body but has trouble releasing sweat from the fabric when not exposed to fresh air. We also couldn't help but notice the slower drying speed of the Oasis (one hour in the spring sun) during our spring testing period. If you want a layer that dries faster, the Patagonia Capilene Thermal Weight Zip-Neck or Ridge Merino Convict are great choices. But after evaluating several different crew designs and materials, this high-performing Icebreaker layer quickly climbed to the top of our list. We attribute this stellar performance to the soft yet durable Merino wool, a great fit that promotes mobility, and a durable construction that limits any chafing or friction while getting after it in the mountains.

Read more: Icebreaker Merino 200 Oasis Crewe review

Though the Icebreaker 200 Oasis Crewe doesn't perform as well as its air-permeable synthetic competitors, we did appreciate the thicker fabric during ski tours early in the spring.
Credit: Trish Matheny

Best for Midweight Breathability


Patagonia Capilene Thermal Weight Zip-Neck - Women's


76
OVERALL
SCORE
  • Warmth 7.0
  • Breathability 9.0
  • Comfort and Fit 7.0
  • Durability 6.0
  • Drying Speed 9.0
  • Layering Ability 8.0
Material: 92% recycled polyester, 8% spandex | Thickness: Midweight
REASONS TO BUY
Superior breathability
Excellent warmth
Long zip neck for venting
Durable blended fabric
Comfortable micro-grid fleece interior
REASONS TO AVOID
Fabric holds odor
Not a thermal weight
Thumb loops lack quality and comfort

The Patagonia Capilene Thermal Weight Zip-Neck quickly stood apart from the competition in terms of warmth and breathability. Our lead tester loves this layer as a stand-alone piece for efficiently shedding sweat accumulated on fall trail runs as well as the base of her cold weather kit while rock climbing during those crisp October nights. While not a thermal weight as advertised, the polyester blended fabric and micro-grid fleece interior gave a memorable performance in terms of exceptional breathability and moisture-wicking capabilities.

Patagonia advertises a Polygiene odor control treatment for the Capilene Thermal, but we found this layer to retain body odor almost immediately, especially when used several days in a row. Again, a natural, Merino layer like the Icebreaker Merino 200 Oasis Crewe will serve you better if you find odor retention particularly offensive. And while we appreciate the thumb loops on the Capilene Thermal in terms of layering ability, the low-quality construction (basically just an elastic band) doesn't inspire confidence they will last for the life of the base layer. That said, this layer offers excellent thermoregulation and breathability thanks to the air-permeable Polartec fabric and the long zip neck. These work together to effectively dump heat and excess sweat during those high-intensity mountain pursuits.

Read more: Patagonia Capilene Thermal Weight Zip-Neck review

We love the versatility of the zip neck on the Capilene Thermal Weight, which helps to increase or release warmth generated during activity.
Credit: Trish Matheny

Compare Products

select up to 5 products to compare
Score Product Price
83
Ridge Merino Convict - Women's
Best Merino Wool Base Layer for Women
$150
Editors' Choice Award
82
Arc'teryx Rho Hoody - Women's
Best Synthetic Base Layer for Women
$130
Editors' Choice Award
82
Black Diamond Solution 150 Merino Quarter Zip - Women's
$145
77
Icebreaker Merino 200 Oasis Crewe - Women's
Best Thermal Crew
$105
Top Pick Award
76
Ridge Merino Aspect Midweight - Women's
Best Value for Merino
$75
Best Buy Award
76
Patagonia Capilene Thermal Weight Zip-Neck - Women's
Best for Midweight Breathability
$109
Top Pick Award
75
Mons Royale Cascade Merino Flex Mock Neck LS
$120
73
Smartwool Intraknit Thermal Merino - Women's
$130
72
REI Co-op Midweight Base Layer Crew - Women's
Best Synthetic Bang for Your Buck
$55
Best Buy Award
72
Patagonia Capilene Midweight Crew - Women's
$79
67
Smartwool Classic Thermal Merino 1/4 Zip - Women's
$120
66
Smartwool Classic All-Season Merino - Women's
$90
66
Kari Traa Rose Light Half Zip
$130
64
Carhartt Base Force Heavyweight 1/4 Zip - Women's
$55
63
REI Co-op Merino 185 Top - Women's
$80
62
Roman Trail Outfitters Merino Long Sleeve - Women's
$60
59
Ortovox 185 Rock'N'Wool Long-Sleeve - Women's
$110

base layer womens - base layers are an important part of any backcountry mountain...
Base layers are an important part of any backcountry mountain objective; we were impressed with the performance of the Oasis Crewe while riding Solar Bowl.
Credit: Steve Mace

Why You Should Trust Us


When making our selection, we take hours researching the best options on the market before selecting the very best and subjecting them to our rigorous side-by-side testing plan. We wear them everywhere we go and have tested them across the world, from the high glaciers of Alaska to the rainy and cool landscapes of Iceland. The base layer tops we test are used for a minimum of three months, and we continue to test them until they see an update throughout the year. We take these tops trail running, backpacking, rafting, climbing, splitboarding, and hiking to determine how each performs during unique experiences in the backcountry. Once we complete our field testing, we evaluate the durability of each layer, noting any tears or snags. Finally, we score across the same metrics to offer a comparative assessment based on our experience.

Our women's base layer testing is divided across six rating metrics:
  • Warmth (25% of total score weighting)
  • Breathability (20% weighting)
  • Comfort and Fit (20% weighting)
  • Durability (15% weighting)
  • Drying Speed (10% weighting)
  • Layering Ability (10% weighting)

Our testing team is led by Trish Matheny and Amber King. After spending over a decade in the Tetons, Trish knows what she wants in base layer performance. An avid rock climber, trail runner, and splitboarder, she wears base layers frequently while exploring the Sierra Nevada Mountains and beyond. As a seasoned gear reviewer, Amber spends her time backpacking into remote places, canyoneering through slot canyons, and finding cool trails to run worldwide. Women she meets along her adventures become additional testers to provide unbiased, diverse, and genuine feedback on all the base layer tops we tested.

Getting high up on some granite is a great way to test the...
Getting high up on some granite is a great way to test the durability and thermoregulation of a performance layer.
Base Layers drying in the sun with Mt. Tom in the background during...
Base Layers drying in the sun with Mt. Tom in the background during our springtime drying tests.
Durable enough for a day of rock climbing wide cracks, the midweight...
Durable enough for a day of rock climbing wide cracks, the midweight Smartwool Intraknite 200 is well-constructed and built to last.

Analysis and Test Results


A base layer top is an integral part of any women's outdoor wardrobe. This piece sits closest to the skin, wicks away moisture, and ultimately keeps you warm and comfortable while tackling summits or lounging around the chalet. The base layer tops we chose are composed of either synthetic materials, Merino wool, or a blend. No tops in this review contain cotton. Throughout testing, we rate each product using five key metrics: warmth, breathability, comfort and fit, layering ability, and durability.


Value


Wondering which tops offer the best performance relative to their price? We understand the importance of the return on your investment. Typically, the largest trade-off in this category lies in the materials used. Merino wool tends to cost more money than synthetic fabrics, and this higher price is passed on to the consumer. The Roman Trail Outfitters Merino Long Sleeve retails for less than half of our top performers. However, its thin materials stretch out over time, and you end up sacrificing durability.

base layer womens - though available for a fraction of the cost, the roman trail merino...
Though available for a fraction of the cost, the Roman Trail Merino does sacrifice some durability.
Credit: Trish Matheny

A couple of our favorite value-based purchases of all the garments that we've tested are the Ridge Merino Aspect Midweight and the REI Midweight Base Layer Crew. The Ridge Merino is on point with some of our top-performing base layers, while the REI Midweight offers incredible value in exchange for sufficient synthetic performance. However, it's also worth considering the long-term value of synthetic tops like the Arc'teryx Rho Hoody. Its superior craftsmanship and high quality make it one of our top choices season after season of use, which reduces its total cost over time.

base layer womens - the ridge merino aspect midweight is a great layer for cool weather...
The Ridge Merino Aspect Midweight is a great layer for cool weather days of the spring and fall when worn alone and features super soft merino if wearing as the base of your cold weather kit.
Credit: Lindsey Fell

Warmth


How many times have you broken a sweat while hiking uphill, only to start shivering once you slow your pace? The base layer tops that offer the highest level of warmth are those that can properly regulate body temperature no matter the activity, whether you're riding the chairlift or Nordic skiing. Different tops offer different fabric weights, which contributes to overall warmth. In general, if you know you will be sitting around in cold weather, choose a thicker option. If you think you're going to be moving a lot more with minimal breaks, choose a thinner option to avoid overheating. A midweight base layer is typically a good compromise.


No Heavyweight Options?


During our testing, we only reviewed lightweight and midweight models. Keep in mind that most of the layers listed here have different weight options. If you like the way a top sounds, check to see what other fabric weights are available.

base layer womens - versatile warmth and sun protection make the rho hoody a great...
Versatile warmth and sun protection make the Rho Hoody a great choice for alpine missions.
Credit: Lisa Coleman

When comparing fabrics, Merino wool stands out — it offers more insulating warmth and breathability, which equates to better thermoregulation overall. For example, the Smartwool Classic Thermal Merino 1/4 Zip is among the warmest and most insulating base layers in this review, packing in 250 g/m² of Merino wool. The Icebreaker Merino 200 Oasis Crewe is similar, with 200 g/m², making it a little less warm but not as thick. And not far behind are our two favorite blended layers, the Ridge Convict and the Black Diamond Solution 150. Both of these layers combine the strength and durability of synthetics with the warmth and odor-resistant qualities of Merino wool. While each layer improves upon warmth by adding a hood and thumb loops, the Convict effectively traps more body heat in its thicker 170 g/m² Merino wool interior.

The Oasis Crewe quickly became one of our favorites, warm enough to...
The Oasis Crewe quickly became one of our favorites, warm enough to be worn on its own during spring training runs, just as the snow starts to melt.
The low profile hood of the Ridge Merino Convict helps increase...
The low profile hood of the Ridge Merino Convict helps increase overall warmth, especially on windy days of inclement weather.

Tops like the Ortovox 185 Rock'N'Wool (185 g/m²) and the Carhartt Base Force Heavyweight still receive high scores but offer just a little less warmth. Both are lighter options for excellent thermoregulation on high-output days like cross-country skiing or trail running.

Most of the polyester tops we've tested don't offer the same "sitting around" warmth as Merino wool. Many are constructed with hollow polyester fibers. When it's cold in the morning, and you pull the top on, it won't feel as cozy as Merino wool simply because all the cold air is locked inside the fibers. However, once you get your body in motion, the layer will conceal the heat generated during your activity. When moving from warm to cold, tops like the Patagonia Capilene Midweight Crew and Arc'teryx Rho Hoody will typically adapt to their environment more readily than Merino wool. Both of these options are warmer synthetic tops than the Smartwool Classic All-Season Merino, for example, which is more breathable and not built for stand-alone warmth. Of them all, the Arc'teryx Rho is our favorite synthetic because of the built-in fleece liner that keeps the skin warm and cozy even after you stop moving. The latest iteration of this layer features a versatile design that offers a neck warmer, hoody, and a full-face balaclava to protect you from inclement weather and radiant sun exposure in the alpine.

base layer womens - the tightly woven diamond weave synthetic fabric on the capilene...
The tightly woven diamond weave synthetic fabric on the Capilene Midweight kept us warm after the sun dipped behind the cliff.
Credit: Lisa Coleman

Breathability


This is the yang to warmth's yin. Without great breathability, you will not have much warmth during your cold-weather adventures. A key metric for thermoregulation, breathability defines how well the fabric allows heat to escape and how well it vents. When worn in a layered system, breathability enables fabrics to move moisture from the skin and through the fabric to the next layer, keeping your skin dry.


Choose a Weight Appropriate to the Activity


Choose lightweight fabric for any of the tops we reviewed if you want something that'll breathe easier. Short-sleeve options are also available sometimes, as are zip necks, which offer more ventilation. If you run hot, lightweight fabric is the way to go, but if you get cold easily, opt for midweight construction.

The open grid pattern of the Ridge Merino Convict allows air to permeate the layer and wick away moisture while the Polartec Power Wool traps essential body heat.
Credit: Trish Matheny

Surprisingly, the Patagonia Capilene Thermal Weight Zip-Neck lands at the top of this metric. Our testers were blown away by the wicking capabilities and fast drying speed of this impressive layer. Though not what we would typically consider a traditional thermal weight, due to its super lightweight and see-through design, the magic is in the breathability that optimizes warmth thanks to a micro-grid fleece interior and releasing sweat through the air permeable polyester fabric. The Ridge Convict features a very similar open grid pattern to the Capilene Thermal Weight but with a much thicker, midweight construction.

base layer womens - the slim fitting capilene thermal weight is great when worn on its...
The slim fitting Capilene Thermal Weight is great when worn on its own or at the base of your layering kit. The long zip neck will help contain or release body heat through the breathable heat design based on current conditions.
Credit: Rebecca Church

Another top that stands out in this metric is the Roman Trail Outfitters Merino. This model is quite warm for its lightweight design, provides excellent thermoregulation through a wide range of temperatures, and also vents well, thanks to its loosely woven fabrics. This is a great layer to consider during the summer months when you're headed high into the alpine, but we recommend leaving it at home during the colder months of winter. That said, the Roman Trail Outfitters top also works well as the base of a nicely layered system, whether beneath a midweight fleece or puffy jacket.

base layer womens - thanks to loosely woven merino wool, we love the roman trail merino...
Thanks to loosely woven Merino wool, we love the Roman Trail Merino for spring skiing or for a little extra warmth during the summer months.
Credit: Trish Matheny


Essentially, the layers that excel at proper ventilation are those constructed from thinner materials and a fabric knit that isn't too tight for moisture to escape. The Smartwool Intraknit Thermal Merino is quite notable here. The stylish and strategically engineered ventilation panels throughout the design work to increase airflow and enhance breathability by featuring a tighter weave with a touch of elastane. The elastane helps to provide enough stretch to move with you during various activities. This midweight layer kept us warm enough during multi-pitch rock climbs in the fall while also dumping enough heat to get after it on long trail runs during the shoulder seasons.

base layer womens - not only does the innovative design of the smartwool intraknite...
Not only does the innovative design of the Smartwool Intraknite Merino 200 look cool, it also offers strategically placed ventilation panels to allow the layer to breathe and release moisture.
Credit: Steve Mace

The 100% synthetic construction of the Patagonia Capilene Midweight Crew is also quite breathable. Its diamond-grid architecture promotes great airflow with a face fabric that cuts the wind when worn independently.

When spending long days rock climbing, our testers loved how well the Black Diamond Solution 150 Merino was able to keep us warm in the sun as well as cool in the shade. This layer features increased breathability through its Nuyarn Merino wool stretch technology and is a joy to wear.

base layer womens - the solution is one of our go-to&#039;s for performance during mountain...
The Solution is one of our go-to's for performance during mountain adventures. We love how well it breathes and how quickly it dries considering the mostly merino construction.
Credit: Steve Mace

Comfort and Fit


When testing for this metric, we assess each top to determine which fabric has the coziest and most versatile fit. This is perhaps the easiest metric to test for; all we have to do is record our notes while we hang around the campfire or enjoy a rest day. We also evaluate how the fabrics feel next to our skin after several days of wear without washing, so we can determine whether or not the feel of the fabric changes over time. In general, we love Merino wool tops with a fitted, stretchy design simply because they offer the maximum level of comfort.


After a few washes and some time on the trails, The Black Diamond Solution 150 Hoody became one of the most comfortable base layers in this review. The Solution features 78% Nuyarn Merino wool and 22% polyester to maintain strength and durability, with a bit of stretch, as well as flatlock hemlines. The Arc'teryx Rho Hoody is also notable thanks to its cozy, fleece-lined polyester and elastane material. We love that the latest iteration features a neck warmer, a hood with a small opening for a ponytail, and a balaclava for maximum cold-weather protection. The fit has changed dramatically from previous iterations — Arc'teryx scrapped the boxy fit and kangaroo pockets for a trim-fitting base layer meant to remain close to the body to minimize any unnecessary bulk. This trim fit also enhances the layer's ability to trap body heat generated during activity due to the lack of draft.

base layer womens - the rho has a trim fit to hug the body without restricting full...
The Rho has a trim fit to hug the body without restricting full range of motion.
Credit: Trish Matheny

The Ridge Convict is another great consideration for a comfortable, well-fitting layer. The flattering fit and feminine style of this top is true to size and super cozy next to skin, thanks to its ultra-fine Merino wool interior.

Our testers love the slim fit of the Air Hoody which kept us...
Our testers love the slim fit of the Air Hoody which kept us comfortable while also keeping its shape during our extensive testing period.
The flattering fit of the Ridge Merino Convict is true to size and...
The flattering fit of the Ridge Merino Convict is true to size and offers length in the sleeves and torso that fits a variety of body shapes, while the ultra-fine Merino wool fibers increase comfort next to skin.


The Ortovox Rock'N'Wool is one of the softest wool options that we tested, featuring a lighter construction and 100% Merino wool sourced from Tasmania; we loved how soft the wool felt next to our skin. However, we were disappointed that the latest version of this shirt is designed with bulkier flatlock seams across both forearms. We found these seams to be distracting and uncomfortable, in addition to bunching beneath layers worn over the top. We hope future versions ditch the seemingly unnecessary thick seams and improve their placement because the wool itself is awesome.

base layer womens - we like the next-to-sin feel of the ortovox rock&#039;n&#039;wool&#039;s fabric...
We like the next-to-sin feel of the Ortovox Rock'n'Wool's fabric, but we are unimpressed with the location and thickness of the seams on the forearm and chest.
Credit: Toby Swimmer

Another super soft Merino wool option that stood out amongst the competition is the Ridge Merino Aspect Midweight. It features a very basic crew construction with strategically placed flatlock seams that reduce bulk and prevent chafing while carrying a heavy pack. Our testers love the long cut and slim fit that effectively trapped our body heat, as well as the discreet yet functional thumb loops that added warmth and structure to the overall design. Similar to the Aspect is the Mons Royale Cascade Merino Flex Mock Neck LS. This top offers a very flattering, slim fit that features a looser-fitting mock neck for additional warmth. The layer offers a short torso length that layers well with high-waisted bottoms and thumb loops to improve ease of layering.

Our testers love the slim fit and ultra fine Merino wool that...
Our testers love the slim fit and ultra fine Merino wool that increased comfort next to skin without sacrificing durability on the Ridge Merino Aspect.
The Mons Royale Mock Neck features a slim fit and low profile that&#039;s...
The Mons Royale Mock Neck features a slim fit and low profile that's both comfortable to wear any easy to layer.

When evaluating the fit of each base layer, we handed these shirts to a group of women who varied in height, weight, and body shape to offer the most objective recommendations possible. Some were tall, while others were short; some had lots of curves, while others had none. In our evaluations, tops with a stretchier and more voluminous fit proved to be the most versatile. We also looked at the relative lengths of the arms and torso to see which provided the best overall coverage. Our lead tester (5'6", 130 lbs) prefers size small in most of these tops but found the Black Diamond Solution 150, and the Kari Traa Rose Light Half Zip to fit better in size Medium.

Do Tall Options Exist?


Need a shirt with a long torso and arms? Luckily we have a host of options. Of synthetic tops, the Arc'teryx Rho features a super stretchy fabric and a longer fit in the arms and torso. The Smartwool Intraknit Thermal, Icebreaker Merino 200 Oasis Crewe, and the Ridge Merino Convict and Aspect also feature a stretchy construction with plenty of length through the arms and extra fabric in the torso.

base layer womens - the smartwool intraknit has a slim, long fit, and is slightly longer...
The Smartwool Intraknit has a slim, long fit, and is slightly longer in the back.
Credit: Steve Mace

Durability


The best base layers out there should last for you to receive the greatest return on your investment. A proper base layer shouldn't shrink, stretch out, pill, or fall apart after just a few months of use. Most importantly, a durable top shouldn't easily succumb to snags and tears after just a few times out on the trail. During our testing period, we shimmied through canyons and bushwhacked through forests to see if the fabric snagged or tore. We also wore each layer with a loaded backpack. After all of this, we inspect each product to evaluate the craftsmanship. In addition, we test each base layer continuously throughout the year and will update this section with our most current recommendations.


A Note on Odor


In all of our tests, the silk and synthetic shirts constructed of polyester retain more smell over time than Merino wool tops. Merino wool can be worn for multiple excursions without washing before odor becomes an issue. Despite a company's best efforts to develop odor-resistant fabrics with polyester fabrics, most will inevitably smell over time, even after washing. If you're self-conscious about a bad-smelling shirt, choose either Tencel or Merino wool.

base layer womens - flatlock seams not only prevent any extra friction or chafing, but...
Flatlock seams not only prevent any extra friction or chafing, but also help to enhance the durability of the naturally odor-free Merino wool design.
Credit: Trish Matheny

It's been many years since we first started testing the Arc'teryx Rho Hoody, and previous versions are still going strong. We have used and abused it while climbing, hiking, splitboarding, trail running, and canyoneering. After many long years of use, there are still no significant areas of wear and tear, and we expect the same to be true of the most current version. The high-quality design features a combination of Merrow and flatlock stitched seams that effectively hold the trim-fitting layer in place without limiting range of motion. Our only caveat is that the fabric retains a little smell. Aside from that, it has truly withstood the test of time and continues to exceed our expectations.

base layer womens - the highly durable merrow and flatlock seam construction hold the...
The highly durable merrow and flatlock seam construction hold the Rho Hoody in place while the stretch polyester allows for full range of motion.
Credit: Trish Matheny

The Patagonia Capilene Midweight is a workhorse. The synthetic fibers are strong and retain their shape, even after being put through the wringer. The Midweight stands apart from other Patagonia options in this review due to the tighter weave of the diamond grid pattern. We question the longevity of the Capilene Thermal Weight — not for lack of quality, but simply due to its thinner, more air permeable, see-through design that optimizes breathability. Our only complaint about this layer is that the thumb loops lack the same quality as the rest of the layers — they are thin and don't inspire long-lasting confidence. Rounding out our synthetic durability favorites is the REI Co-op Midweight featuring reinforced flatlock seams as well as thicker, more comfortable thumb loops.

base layer womens - featuring a longer cut, thumb loops, and tightly woven fabric, the...
Featuring a longer cut, thumb loops, and tightly woven fabric, the REI Co-op Midweight Base Layer Crew offers enough warmth when worn alone or below other insulation.
Credit: Trish Matheny

Merino wool contenders are less durable than synthetic options, but they don't hold onto odor. Of these, the Kari Traa Rose Half Zip is the most durable. It has a tightly knit face fabric that doesn't easily snag. The nylon fibers are shorter and have proven to be more durable and a better option for those needing a top for high-friction sports like canyoneering, bushwhacking, or rock climbing. We'd also like to highlight the Nuyarn stretch Merino wool found in the Black Diamond Solution 150 that impressed us during our winter testing period when we snagged our sleeves on a tree. After ripping a hole in the material, it didn't continue running throughout the length of the fabric like other more delicate Merino wool contenders in this review. The hole has remained small, allowing for continued use. And not to be overlooked, the Ridge Convict features a durable polyester exterior that effectively protects the ultra-fine Merino wool interior.

base layer womens - the versatile solution 150 performed well in nearly every metric...
The versatile Solution 150 performed well in nearly every metric including the durability of the blended fabric.
Credit: Steve Mace

Drying Speed


When selecting a base layer for your next outdoor adventure, drying speed could truly make or break the decision. It's important that the layer sheds moisture generated during activity while also drying quickly on the body when exposed to fresh air.


We immediately noticed a trend when we started recording drying speeds for each base layer. The synthetic or Merino wool and polyester blended layers offered the fastest drying speeds, much faster than their 100% Merino wool equivalents. We approached these tests from several different angles, including drying on a line, drying on the body, and drying overnight. Now we are confident to report back with our top performers.

We tested each and every base layer side by side in order to objectively determine the layers with the fastest drying speeds.
Credit: Trish Matheny

At only 37 minutes on the line and 25 minutes on the body, the Patagonia Capilene Thermal Weight Zip-Neck was the fastest to dry. Unsurprisingly, this base layer boasts great breathability due to the porous fabric that allows air to flow through and wick moisture away from the skin.

The Ridge Convict had a drying speed of 40 minutes on the line and only 10 minutes on the body, and the Arc'teryx Rho Hoody dried in 40 minutes on the line and 25 minutes on the body. The open grid pattern truly harnesses the wicking capability of its synthetic exterior while simultaneously allowing air to permeate the layer and offer a speedy drying time. Other impressive layers in this metric are the Ridge Merino Aspect Midweight and the Patagonia Capilene Midweight Crew with similar drying speeds at 49 minutes on the line and between 30-35 minutes on the body.

base layer womens - the convict only requires 40 minutes to fully dry on the line.
The Convict only requires 40 minutes to fully dry on the line.
Credit: Trish Matheny

Layering Ability


A good base layer should be versatile and easy to use within a layering system. While most long-underwear tops are presumably that "next-to-skin" layer, it is a bonus when you can wear a tank or tee beneath when conditions are expected to warm up. Not only that, but you want to ensure that you can throw layers on top and remove them without too much effort. Here, we evaluate the knit of the fabric and spend time trying on each one with different layers over the top. Base layers that perform best in this category feature slippery face fabrics, a thinner construction, and thumb loops.


Synthetic layers traditionally have more rigid fibers that, in combination, make for easy layering. The Rho Hoody is one of the easier options to layer thanks to its frictionless face fabric that slides smoothly against even the fleeciest of mid-layers. The latest iteration features a much trimmer fit and minimal design that also improves layering by reducing bulk, especially in the hood, which features a small opening for a ponytail. The Black Diamond Solution 150 Merino features a streamlined design complete with thumbholes that help increase the ease of layering, as they hold the layer in place while putting on gloves or a midweight layer over the top.

The thumbholes help increase the ease of layering for the Merino...
The thumbholes help increase the ease of layering for the Merino Solution 150.
This unique hole in the Rho Hoody is meant for a pony tail so as to...
This unique hole in the Rho Hoody is meant for a pony tail so as to reduce any bulk within the hood.

The Patagonia Capilene Midweight and the Patagonia Capilene Thermal Weight Zip-Neck are both great layering options with built-in thumb loops that keep the arms in place, while the REI Co-op Midweight features a frictionless face fabric, in addition to a super stretchy design that hugs the body. All are great options in this category.

base layer womens - the rei co-op midweight base layer crew is a great choice when worn...
The REI Co-op Midweight Base Layer Crew is a great choice when worn alone for fall weather days and it easily layers below a puffy for colder, shadier areas.
Credit: Lindsey Fell

Of the Merino wool competitors, thinner options like the Roman Trail Outfitters, Smartwool Classic All-Season Merino, and Ridge Merino Aspect are much easier to layer than thicker options. Layers like the Kari Traa Rose and the Smartwool Intraknit Thermal work well, too, because of how fitted they are, making sliding layers over them easy.

base layer womens - we had some fun putting these layers to the ultimate test while...
We had some fun putting these layers to the ultimate test while meticulously evaluating warmth, breathability, comfort and fit, durability, drying speed, and layering ability
Credit: Meredith Jabis

Conclusion


The clothing layer next to your skin is integral for keeping you warm and comfortable while exploring the great outdoors. Whether you're snuggling up next to the fire or shredding down a double black diamond on the ski hill, aim for one that performs to meet your individual needs. We've done the hard work and tested some of the best options available. We hope our recommendations help you select the best base layer for your next backcountry adventure.

Trish Matheny and Amber King