Your baselayer may not be the most exciting part of your layering system, but make no mistake: It’s certainly one of the most important. As a next-to-skin piece, baselayers are tasked with pulling moisture away from your body and regulating your core temperature, which is especially useful for outdoor activities like skiing, hiking, and climbing. Below are our top picks for the best women’s baselayers of the 2023-2024 season, from premium, warm, and naturally odor-resistant merino wool options to cheaper synthetic alternatives. For more information, see our women’s baselayer comparison table and buying advice below the picks.
- Best All-Around Baselayer for the Cold: Smartwool Classic Thermal Merino ¼-Zip
- Best Synthetic Women’s Baselayer: Patagonia Capilene Midweight Crew
- Best Budget Women’s Baselayer: REI Co-op Midweight Base Layer Crew
- Best Women's Baselayer for Active Use: Smartwool Intraknit Thermal Merino Crew
- Most Durable Women’s Baselayer: NW Alpine Black Spider Hoody
Best All-Around Baselayer for the Cold
Material: 100% merino wool
What we like: Extremely warm and soft; merino is resistant to stink.
What we don’t: Too thick for high-output activity.
Merino wool is our favorite baselayer material for many reasons: It’s soft and comfortable, provides incredible warmth for the weight, and effectively wicks moisture away from your skin. Smartwool’s popular Classic Thermal is a shining example, combining all the performance benefits of wool in a well-built and good-looking package. With a fairly heavy dose of pure merino (250g/m²), the Classic Thermal is built to keep you warm during winter activities like resort skiing and snowshoeing, yet is still cozy enough to wear around the house on snow days. Fit-wise, the women's version is fairly snug, but added give in the fabric means it effectively breathes and wicks sweat without feeling restrictive. And for active use or warmer days, we really appreciate the ability to dump excess heat via the 8-inch zipper at the top (which also allows the layer to slide on nicely over a helmet).
All that said, merino wool does have its downsides. First and foremost, the material doesn’t come cheap, and the Smartwool is pricey for a baselayer at $120. If you’re on a tight budget and don’t mind compromising in areas like comfort and odor resistance, you can save considerably with one of the polyester options below, including Patagonia’s popular Capilene. Polyester is also inherently more durable than merino and wicks moisture more effectively, making it a better choice for sweat-inducing activities. But for resort skiing, mellow snowshoeing, and casual days around town, the comfort and warmth of wool are well worth its inherent tradeoffs, making the Classic Thermal our favorite cold-weather baselayer this year. And if you like the warmth and construction but prefer a different style, it’s also sold in a Crew Top ($115) and 1/2-Zip Hoodie ($145), as well as matching bottoms of different lengths.
See the Smartwool Classic Thermal Merino 1/4 Zip
Best Synthetic Women’s Baselayer
Material: 100% polyester
What we like: Polyester is more affordable, durable, and breathable than wool.
What we don’t: Less soft and doesn’t resist odor as well as a merino baselayer.
As we touched on above, polyester baselayers typically are cheaper and more durable than their merino counterparts, and are much better suited for intense activity. Our top synthetic pick this year is Patagonia’s Capilene Midweight Crew, which will save you around $40 compared to the Smartwool above while still offering great all-around performance. In addition to improved moisture-wicking, the Capilene feels smooth against the skin, features thoughtful touches like low-profile thumb loops and underarm gussets, and is made with 100% recycled materials (a nice nod to Patagonia’s ongoing sustainability focus). Long-term durability is the cherry on top—we have Capilene tops that are multiple years old and showing minimal wear despite heavy use.
What do you sacrifice by opting for a synthetic baselayer? While the Capilene is comfortable for a polyester design, it’s still a tangible step down in softness compared to the merino competition. Further, despite Patagonia’s HeiQ Pure anti-odor treatment, the Capilene builds stink more readily and will require fairly frequent washing. And unrelated to the construction, the Capilene is dubbed a “slim fit” by Patagonia, which may not work for some body shapes (it’s noticeably trim around the waist in particular). But maintenance is a breeze (you can throw it in the dryer with other clothes), and not everyone wants to spend $100 or more on a baselayer, which is why we love Patagonia’s Capilene collection.
See the Patagonia Capilene Midweight Crew
Best Budget Women’s Baselayer
Materials: 92% polyester, 8% spandex
What we like: Similar warmth as the Smartwool Classic Thermal above at less than half the price.
What we don’t: Not a standout in odor resistance and runs small.
It’s not cheap to assemble a winter layering system from scratch, but the good news is there are a number of affordable, well-built baselayers on the market. REI Co-op’s Midweight Long-Sleeve Base Layer Top is a crowd favorite: For just $55 (less than half the price of our top-ranked Smartwool), the REI is warm, regulates temperature well, and has helpful touches like flat seams and four-way stretch to minimize bulk and maximize mobility (respectively). As we’ve come to expect from REI, the Midweight Long-Sleeve also comes in a nice variety of size and colorway options, from classic black and navy to bright yellow. It’s also offered in a half-zip option for just $5 more.
REI’s Midweight is an undeniably enticing value, especially considering the long-term durability advantage over merino wool. That said, although the Co-op’s fabric is comfortably silky, it can’t compete with merino or even Patagonia’s Capilene above in terms of softness and comfort. It’s also more prone to holding in body odor, which means you’ll probably find yourself putting the REI through the wash more often. Finally, the REI lacks thumb holes, which won’t be a deal-breaker for most—but they do make it easier to add layers overtop. But we keep coming back to value: The REI Midweight is an unquestionably well-built baselayer for the price, earning it our endorsement as the top budget pick this season.
See the REI Midweight Long-Sleeve
Best Women's Baselayer for Active Use
Materials: 53% merino wool, 45% polyester, 2% elastane
What we like: One of just a few merino baselayers that we’ll confidently recommend for high-output use.
What we don’t: Snug fit and techy appearance put it squarely in the performance category.
Smartwool’s Classic Thermal above is a nice match for activities like resort skiing and snowshoeing, but it’s too thick and insulative for high-intensity uses like cross-country skiing or backcountry touring. Enter Smartwool’s own Intraknit Thermal, which is purpose-built to keep you comfortable when working up a sweat in cool to cold conditions. Compared to the Classic Thermal’s all-merino build, the Intraknit’s generous use of polyester (45%) translates to a noticeable boost in both breathability and durability, and Smartwool also included mesh ventilation zones in high-heat areas like the upper back and core. For reference, we’ve worn the Intraknit for all sorts of heart-pumping winter pursuits—from Nordic skiing to breaking trail in waist-deep powder—and found the balance of warmth and breathability hard to beat. Plus, you still get all the benefits of merino, including good odor resistance and a soft-next-to-skin feel.
When deciding between Smartwool’s Classic Thermal above and the Intraknit Thermal here, the main consideration is end use. If you want a more casually minded top to wear both on the slopes and to après, the Classic’s roomier fit and less technical appearance is likely the better choice (we also wear it a lot as an outer layer while hiking or backpacking). On the other hand, the snug-fitting Intraknit is more ideal as a next-to-skin layer for active pursuits and will dump heat much more effectively (our go-to combination is the Intraknit and a windbreaker jacket). Finally, it’s worth noting that Smartwool also makes the Intraknit Active, a thinner variation that’s best suited for mild conditions... Read in-depth review
See the Smartwool Intraknit Thermal Merino Crew
Most Durable Women’s Baselayer
Materials: 93% polyester, 7% spandex
What we like: A highly durable baselayer that can pull double duty as an outer layer.
What we don’t: Pricey for the construction; not as soft or warm as merino offerings.
The baselayers above are great for wearing under a shell and/or midlayer, but NW Alpine’s Black Spider Hoody stands out for how well it functions when worn by itself. The Polartec Power Grid fabric is warm and comfortable but highly resistant to tears and abrasion thanks to the tight weave, and the touch of spandex adds a nice dose of stretch for mobility-dependent activities. For reference, we’ve put ours through more than eight years of climbing abuse—much of the time without a jacket over top—and it has yet to develop any holes or tears. The rest of the design is equally well executed, including a long cut that stays put under a hipbelt or harness, low-profile hood that fits under a helmet, quarter-length front zipper, small chest pocket, and thumb loops.
It's important to note that NW Alpine Black Spider Hoody is not your standard baselayer—with a roomier fit and great standalone performance, you'll probably be layering it overtop a tank top or T-shirt. Further, it's a bit bulkier than most of the competition, noticeably less soft than merino offerings, and—in our experience—doesn't measure up in terms of warmth-for-weight. In addition, $135 is a hefty price tag for a polyester baselayer, and the Black Spider can often be hard to find in stock online or in stores. But the NW Alpine is nevertheless impressive in terms of durability and versatility, which set it apart as a highly functional and long-lasting performance piece.
See the NW Alpine Black Spider Hoody
Best of the Rest
Materials: 84% merino, 16% nylon
What we like: Fun style, great fit and finish, and a Golidlocks level of warmth.
What we don’t: The high neck style doesn’t ventilate well.
A family-run operation based out of California’s Eastern Sierra, Ridge Merino offers a small collection of high-quality yet affordable merino wool baselayers. Their Aspect High Neck Top quickly became our go-to long-sleeve last season. Its 180-gram weight is just the right thickness for mild conditions or high-output activities, and it’s so soft and cozy that we can’t help but wear it around home, too. What’s more, the turtleneck is a refreshing change from standard crew and quarter-zip styles and is long enough to extend over the face for added coverage. To top it all off, the Aspect High Neck is just $80 (the crew is $75), making it one of the most affordable merino wool baselayers on the market.
Similar to other lightweight merino offerings (like the Smartwool Classic All-Season below), Ridge added 16% nylon to help strengthen the Aspect’s thin merino wool build. They’ve also done a great job paying attention to the finer details: The Aspect High Neck features well-designed thumb loops that disappear into the cuffs, a very discreet headphones port (we question the utility of this addition), and a long cut that doesn’t ride up. Added up, we’re very impressed with the Ridge Merino: For mild conditions or high-intensity activities in colder temperatures, it’s one of our favorite designs on the market (you can also opt for a quarter-zip version for better temperature regulation). And it’s worth mentioning Ridge Merino’s heavyweight Inversion, which features thick (270g/m²) 100% merino wool.
See the Ridge Merino Aspect Merino High Neck
Materials: 51% merino wool, 49% polyester
What we like: Scuba-style hood is one of our favorite designs; excellent warmth for the weight.
What we don’t: Lacking in wind and abrasion resistance.
Patagonia’s Capilene collection is legendary in the world of baselayers, running the gamut from thick, thermal-weight designs to lightweight T-shirts and long-sleeve layers for hiking. The midweight Capilene Air Hoody is a real standout in the lineup, merging functional warmth with a thoughtful feature set and nice sustainability slant. We love the scuba-style hood in particular: It adds an incredible amount of warmth, offers great coverage without restricting vision, and has a low-profile shape that easily slides under a climbing or ski helmet. On blustery and cold winter days when you really need to hunker down in your layers, it's a nice alternative to a balaclava that's much easier to pull on and off.
What’s not to like with the Patagonia Capilene Air Hoody? First, despite the healthy amount of polyester in the construction, we developed multiple holes and runs on our hoody in a matter of weeks. We also found that the knit-like exterior is noticeably permeable to wind, and the fabric tends to pill and act as a catch-all for hair, fuzz, and more. In other words, the Capilene Air works best under another layer or two. Finally, some women may want to add a light layer underneath, as the more open weave gives the lighter colorways a slightly translucent look. But with great odor resistance, impressive wicking and drying properties, and one of the warmest, coziest hoods we know of, the Capilene Air is a fantastic next-to-skin piece. If you don’t plan to utilize the hood, it’s also sold in a standard crew-neck version that will save you $20, and the matching bottoms are equally cozy and light.
See the Patagonia Capilene Air Hoody
Materials: 100% polyester
What we like: Cozy warmth combined with excellent breathability and moisture wicking.
What we don’t: Pricier than the Patagonia Capilene Midweight.
The Patagonia Capilene above is our favorite synthetic baselayer, but you can step up performance a notch with the TNF Summit Pro 120 here. The highlight of the 100%-polyester Summit Pro is its DotKnit fabric, which features a pattern of small holes that help to increase temperature regulation. In practice, we were really impressed with the baselayer’s performance: It provides a surprising amount of warmth but effectively dumps heat and moisture during intense activity. What’s more, we found the trim (yet not too snug) fit to be a great match for serious movement.
As we mentioned above, we almost always prefer synthetic over wool for mild conditions or when we anticipate working up a sweat (the Intraknit Thermal above is a notable outlier with 53% merino). And while synthetics don’t always measure up to wool in terms of fit, finish, and comfort, the Summit Pro is a noteworthy exception: The next-to-skin feel is excellent, and even after a year of consistent use, our shirt has only collected a couple of snags. The high-performance design will cost you around $20 more than the Capilene Midweight, but the extra investment is worth it for those who routinely generate a sweat.
See The North Face Summit Pro 120 Crew
Material: 100% merino wool
What we like: Excellent balance of breathability and warmth.
What we don’t: Some won’t love the technical fit.
New Zealand-based Icebreaker may lack the name recognition of brands like Smartwool and Patagonia, but make no mistake: This merino wool specialist is the real deal. The popular 200 Oasis Crew here is a testament to their top-end quality: It’s made from 100% merino wool, is super soft, and has a performance fit that works well for skiing and cool-weather hiking. We also appreciate Icebreaker’s sustainability focus and transparency about production practices, including working closely with local sheep farmers to ensure that animals are treated humanely with access to clean water, adequate nutrition, shelter, and open pastures.
Our main gripe with the 200 Oasis is its snug fit, which tends to ride up around our midsection and doesn't layer well over a T-shirt. As a result, we don't recommend the Icebreaker if you anticipate wanting to wear your baselayer as a standalone piece (it's not a great choice for hiking), but the skin-tight design is nevertheless warm and low-profile under a midlayer. And compared to the Smartwool Classic Thermal above, the Icebreaker's dense weave doesn’t release hot air quite as efficiently—despite having a lighter fabric weight (200 vs. 250g/m²)—and can start to feel muggy when you’re working up a sweat. But the Oasis does wins out in next-to-skin softness, and it's hard to knock the premium craftsmanship of New Zealand-based Icebreaker. For resort or backcountry skiing and other winter use, it's a simple yet high-end merino baselayer that delivers a good dose of warmth.
See the Icebreaker 200 Oasis Crew
Materials: 100% polyester
What we like: A lightweight and breathable top for mild conditions and intense activity.
What we don’t: Not as soft or odor-resistant as merino; material is prone to pilling and snagging.
The Smartwool Intraknit Thermal above is our top pick for high-output use in cool to cold conditions, but for shoulder-season and even summertime use, we turn to Outdoor Research’s thinner Echo Hoodie. For reference, the popular Echo collection features free-flowing polyester in a number of different styles including a tank, short-sleeve shirt, and crew and quarter-zip tops (among others). The Hoodie listed here stands apart for its versatility: Wear it as a breathable baselayer on a high-output spring ski tour, as a winter running shirt, or as a sun hoody for bluebird days on the rock. And compared to other offerings, the hood is a really nice addition that extends the Echo’s warmth, coverage, and sun protection above the neck.
The Echo is an incredibly breathable baselayer and wicks moisture far better than merino, but it does have a few shortcomings. Specifically, the fabric is prone to pilling and snagging, and it lacks the soft next-to-skin feel of merino offerings like the Ridge Merino Aspect above and Smartwool Classic All-Season below. And despite Outdoor Research’s use of ActiveFresh Odor Control, the Echo is also known to hold on to stink. Finally, in terms of sun protection, it has a lower UPF rating than most sun shirts (15 to 20, depending on color). But minor gripes aside, the Echo manages moisture better than most offerings here, making it one of our favorite baselayers for mild conditions or high-output activity in any season. If you’re hard on your gear and wary of spending $75 on a product that may only last a season or two, it might be worth considering a synthetic option like Patagonia’s Long-Sleeved Capilene Cool Daily ($49), which is a thinner variation of their Capilene Midweight above.
See the Outdoor Research Echo Hoodie
Material: 100% merino wool
What we like: Supremely soft, warm, and fun styling.
What we don’t: Too thick for shoulder-season use.
Norwegian brand Kari Traa bucks the shrink-it-and-pink-it trend with a lineup of high-performance outerwear designed for women, by women. You won’t find boxy or bland baselayers here—Kari Traa, the Olympic freestyle skier who founded her namesake company, places a high priority on fun color schemes and flattering shapes. In short, the brand represents the intersection of technical performance and feminine styling that the market has long needed. The Rose Half-Zip is one of their most popular offerings and rife with thoughtful features and details, including a form-fitting design, tall collar with a ventilating front zip and chin guard, high-quality cuffs, and flat seams. And the styling is hard to beat: The vibrant snowflake pattern and contrasting underarm panels give the piece a decidedly modern and elegant look with a healthy selection of colorways to boot.
Like the Smartwool Classic Thermal above, the Kari Traa Rose is made with 100% merino wool, which translates to excellent temperature regulation, odor control, and next-to-skin comfort. But despite Kari Traa's "midweight" designation, the Rose is a good deal thicker and warmer than the Smartwool, and the fit is noticeably snugger (you may want to size up depending on your intended use). In the end, we love this layer for resort skiing and snowboarding, but it's overkill for mild conditions or active use. For a step down in warmth, check out their Edith and Else tops, which feature 220 and 210-gram fabrics, respectively (the Rose is 240g).
See the Kari Traa Rose Half-Zip
Material: 100% polypropylene
What we like: A comfy, stylish, and performance-ready baselayer for under $50.
What we don’t: Limited warmth and tight fit.
Helly Hansen’s Lifa Stripe Crew goes head-to-head with the REI above as a well-rounded budget option. The lightweight build is a step down in warmth and thickness from the midweight REI, but it will still keep you dry and decently cozy in most conditions. The headliner is the Lifa fabric, which is made from polypropylene and specializes in wicking moisture away from the skin (in our experience, it performs better than polyester). Tack on a snug, athletic fit, and the Lifa Stripe is a great next-to-skin layer for high-output activities like backcountry skiing and hiking. At just $45 and a scant 3.5 ounces, Helly Hansen managed to pack in an impressive amount of performance at a very low cost and weight.
What gives the REI Midweight the edge over the Helly Hansen Lifa Stripe in our rankings? The biggest factor is warmth: The polypro build isn’t as warm as polyester, meaning you'll want to pair it with a solid midlayer or insulated shell in cold conditions. What's more, the Helly Hansen can't match merino wool when it comes to next-to-skin feel, and the extra-tight fit will be polarizing for some. The Lifa may be worth the tradeoffs for high-output use, but if you value warmth over breathability, we think it’s worth opting for one of REI’s budget-oriented polyester options (including the $55 Midweight above or the $40 Lightweight Crew). Alternatively, Helly Hansen offers the midweight Lifa Merino Crew ($100), which features a merino wool exterior and polypropylene lining.
See the Helly Hansen Lifa Stripe Crew
Materials: 84% polyester, 16% elastane
What we like: A great-looking synthetic baselayer for high-output activities.
What we don’t: Expensive; too warm for shoulder-season use.
Arc’teryx places a premium on high performance, which shows in their baselayer collection. Their Rho Crew Neck Long Sleeve is tailor-made for regulating body temperature in cold weather, whether you’re moving or standing still. The key here is Arc’teryx’s 190-gram Torrent material, which is a step up from most polyester/elastane blends: It doesn’t stretch out of shape or retain odor, is perfectly supple and stretchy, and features a cozy brushed liner for excellent comfort and moisture management. What’s more, the fit is particularly flattering (not too tight, not too loose, and just the right amount of tapering), while the slight V shape in the neckline adds a nice dose of flair—more than once, we’ve received compliments when wearing this shirt out casually.
Arc’teryx recommends the Rho Crew Neck for low-output activities in cool temperatures, but we’ve found it to be a surprisingly good breather for its warmth and weight. In fact, it was one of our go-to baselayers last winter for outdoor training, including road running and Nordic skiing (we usually paired it with a lightweight softshell or windbreaker). But it’s not the best shoulder-season piece: As temperatures rose above freezing, we started to reach for thinner alternatives. As with most Arc’teryx products, the Rho Crew Neck doesn’t come cheap—$110 is a high price to pay for a synthetic baselayer—but it pulls off a non-merino build better than most. For those who prefer wool, we're also big fans of the Rho Merino Wool Crew Neck LS ($120), which features a warm dose of 240-gram merino (95% wool, 5% elastane).
See the Arc'teryx Rho Crew Neck LS
Materials: 88% merino wool, 12% nylon
What we like: Light and breathable enough to wear year-round.
What we don’t: Thin materials require more care.
Smartwool’s Classic Thermal above is our favorite baselayer for cold weather, but it’s decidedly overbuilt for mild conditions. For warmer temperatures, their Classic All-Season is similarly well built but noticeably thinner (150g/m²) and more breathable. Additionally, unlike the Thermal’s pure wool construction, the All-Season adds 12% nylon to the mix for a boost in durability, and weight goes down significantly from 8.3 ounces to a scant 4.7 (the lack of zipper helps). In other words, you’re still getting the coziness and moisture-wicking capabilities of merino wool, but in a much lighter and airier-feeling package.
All told, the Classic All-Season is a nice match for demanding winter activities like cross-country skiing and cold-weather running. The lightweight construction also makes it appealing for more casual outings in milder temperatures, including shoulder-season hikes and hanging out in camp on cool summer nights. However, the tradeoff to the Classic All-Season’s thinner build is that it’s more prone to developing holes and tears, especially if you regularly throw it in the dryer. But we love the Smartwool’s combination of comfort and breathability, earning it a spot high on our list this season.
See the Smartwool Classic All-Season Merino
Materials: 92% polyester, 8% spandex jersey
What we like: Light but cozy with a nice dose of style.
What we don’t: Pricier than most synthetic competitors and not particularly performance-oriented.
The third and final option from Patagonia’s popular Capilene collection to make our list this season is the Long-Sleeved Capilene Thermal Crew. Right off the bat, we’ll note that the “thermal” designation is a bit of a misnomer: The synthetic build is super lightweight (right behind the TNF Summit Pro above) and noticeably more breathable than the merino-heavy Capilene Air above. For reference, we wore a slightly pared-down version of the Capilene Thermal on a one-day ascent of Washington’s Mount Stuart this past June and managed to stay comfortable throughout the entire push. And it doesn’t get much more comfortable: The Polartec Power Grid fabric’s open-grid weave has a really supple and soft next-to-skin feel, which is a notable upgrade from the scratchy interior of our well-worn Capilene Air.
All that said, the Capilene Thermal Crew lags behind many synthetic competitors in long-term durability. Most notably, we experienced considerable pilling around the cuffs, which is largely cosmetic but nevertheless worth considering given the steep price tag. On the bright side, the fabric is good at resisting tears and holes, and the offset shoulder seams help minimize wear and chafing underneath pack straps. We also love the accommodating fit and pass-through front pocket, which add a nice dose of style for casual and around-town use. It’s true that the Capilene Thermal is the priciest synthetic design on our list and less performance-ready than many of the picks above, but the combination of comfort, breathability, and everyday-friendly looks is enough to earn it a spot on our list.
See the Long-Sleeved Capilene Thermal Crew
Material: 100% merino wool
What we like: Competitive mix of warmth and breathability for working hard in cold weather.
What we don’t: $20 pricier than the Smartwool Intraknit above without enough to show for it.
If Smartwool’s Intraknit Thermal above caught your eye, it’s also worth considering Icebreaker’s similarly intentioned 200 ZoneKnit Crew. Like the Smartwool, the Icebreaker is a midweight design intended for working hard in cold weather, but trades the Intraknit’s partial-wool build for 100% merino. This translates to a boost in comfort, warmth, and odor resistance, making the ZoneKnit a great choice for high-output days in the cold. And Icebreaker didn’t skimp on the smaller details, including gusseted underarms for maximizing mobility, flatlock seams to minimize chafing underneath pack straps, thumb loops (which the Smartwool lacks) for smooth layering, and a drop tail hem that adds coverage when sitting down or bending over.
Why do we rank the Smartwool Intraknit above the Icebreaker ZoneKnit? While the all-merino build is great for next-to-skin comfort and stink prevention, it’s a step down from the Smartwool’s merino/polyester/elastane blend in terms of moisture wicking and durability. We generally prefer synthetic baselayers for sweat-inducing activities like nordic skiing and winter running (the Smartwool is a key exception); despite its active intentions, the Icebreaker will likely cause you to overheat. And although subjective, we’re not big fans of the ZoneKnit’s styling: The Icebreaker logo is positioned front and center, the stripes down the sides of each arm give the design a fairly technical look, and there’s an awkward seam running across the middle of the torso. A final clincher is the $20 increase in price over the Smartwool. But if you can score the ZoneKnit at a discount or simply prefer the all-merino construction, it’s another capable option for high-output use in the winter months.
See the Icebreaker 200 ZoneKnit Crew
Materials: 78% merino, 22% polyester
What we like: Innovative construction combines the performance benefits of merino and synthetic.
What we don’t: Expensive.
Black Diamond’s Solution 150 Merino Crew might look relatively unassuming on the outside, but there’s a lot more to this piece than meets the eye. The Solution’s calling card is its innovative NuYarn construction: Many manufacturers weave synthetic fibers together with merino to reap the benefits of both materials, but NuYarn takes it to the next level, wrapping nylon with extra-fine merino fibers in a thread that exudes technical performance down to its literal core. The net result is better durability and tear resistance compared to full merino designs like the Icebreaker 200 Oasis above, and the Solution also dries out very quickly when wet (great news for women who are prone to working up a sweat). All told, it’s a highly effective mix that merges the best properties of both fabrics.
After wearing the Solution 150 for six days straight while hiking in Patagonia, we were impressed with how well it held its shape and resisted odor. Under a loaded backpack, the offset shoulder stitching was comfortable and mitigated pressure points, and the thumb loops are sleek and well constructed. The BD also has a more relaxed fit than super-snug offerings like the Smartwool Intraknit Thermal and Icebreaker Oasis above, which many women will prefer. In fact, our only real gripe with the Solution 150 is its $135 price tag, which is $5 more than the Intraknit and $45 more than Smartwool’s comparable Classic All-Season above. But cost aside, the Solution offers solid all-around performance and will last longer than most all-merino baselayers without any major compromise in comfort, which is no easy feat.
See the Black Diamond Solution 150
Material: 100% merino wool
What we like: Proven merino performance, fun styling, and nice sustainability slant.
What we don’t: A little pricey; we have concerns about long-term durability.
Quality wool baselayers are a dime a dozen in 2023, but Ortovox’s 185 Rock'N'Wool Long Sleeve stands out for a few reasons. First, the Ortovox Wool Promise ensures that their products come from ethical and certified sheep farms. And second, we just can’t get enough of the styling on the Rock’N’Wool—if you want a merino baselayer with some flair, the multi-colored designs really pop in the conservative and largely bland baselayer market. And like the chart-topping Smartwool, the Rock’N’Wool is made with 100% merino, which means you get uncompromised odor resistance, great temperature regulation, and a cozy, soft touch. For a versatile and breathable next-to-skin layer that can take you straight from skin track to après, the Ortovox 185 is an eye-catching but still very capable choice.
At 185g/m², the Rock'N'Wool Long Sleeve is lighter than our top-ranked Smartwool Classic Thermal, meaning it’s more suitable for shoulder-season and high-output activities. That said, the thin fabric, paired with the fact that it’s not blended with a synthetic material, does make us concerned about the Ortovox’s long-term durability (even Smartwool’s 150-gram All-Season features a merino/nylon blend). Ortovox does offer their 230 Competition Long Sleeve, which is a step up in warmth with 240g/m² wool (the product name is a little misleading) and adds polyamide (41%) and elastane (2%) for a considerable boost in tear resistance. Another in-house alternative is the 120 Comp Light Long-Sleeve, a seamless, high-performance design that's great for high-octane efforts. All are excellent performance pieces, and a final decision will come down to how you prioritize warmth, breathability, and durability.
See the Ortovox Rock'N'Wool Long Sleeve
Material: 100% merino wool
What we like: Functional warmth and flattering cut.
What we don’t: Expensive for an REI product.
REI’s Midweight above is our favorite budget design this year, but the polyester construction falls short in terms of softness and odor-fighting ability. Enter their Merino 185 Long-Sleeve Half-Zip, which swaps in a full merino build that’s soft, has a good amount of stretch, and wicks moisture effectively. In terms of warmth, the 185-gram REI beats out thinner options like the Smartwool Classic All-Season above (150 g/²); we’ve found the midweight design to offer a really versatile level of warmth whether you’re backpacking or cross-country skiing. Finally, the fit is spot-on for many women with enough room to move around and modest tapering at the waist to add shape. In our experience, many REI products fit on the boxy and baggy side, but that’s not the case with the Merino 185 Half-Zip.
However, while the Merino 185 Half-Zip doesn’t suffer from the typical fit issues we anticipated, it does cost more than expected for an REI product. For reference, Icebreaker’s popular 200 Oasis Crew above is a noticeable step up in warmth for only $15 more, although you do get a front zip and higher collar on the REI. And for $10 less, Ridge Merino’s Aspect offers competitive warmth (180g/m²) alongside a great fit and finish. It’s worth mentioning that the REI Merino 185 features 100% merino, which gives up a little abrasion resistance (especially with the thin build) but results in an extra-soft feel. But in the end, the REI doesn’t quite stand out from a value perspective, which is why we rank it here.
See the REI Co-op Merino 185 Half-Zip
|Smartwool Classic Thermal 1/4 Zip||$120||Mid/heavyweight||100% merino wool||250||8.3 oz.|
|Patagonia Capilene Midweight Crew||$79||Midweight||100% polyester||147||5.4 oz.|
|REI Co-op Midweight Long-Sleeve||$55||Midweight||92% polyester, 8% spandex||Unavail.||Unavail.|
|Smartwool Intraknit Thermal Crew||$130||Midweight||53% merino, 45% polyester, 2% elastane||200||6.4 oz.|
|NW Alpine Black Spider Hoody||$135||Midweight||93% polyester, 7% spandex||197||8 oz.|
|Ridge Merino Aspect High Neck||$80||Midweight||84% merino, 16% nylon||180||6.6 oz.|
|Patagonia Capilene Air Hoody||$159||Midweight||51% merino, 49% polyester||190||5.8 oz.|
|The North Face Summit Pro 120||$100||Light/midweight||100% polyester||120||4.6 oz.|
|Icebreaker 200 Oasis Crew||$105||Miweight||100% merino wool||200||6.5 oz.|
|Outdoor Research Echo Hoodie||$75||Lightweight||100% polyester||Unavail.||4.0 oz.|
|Kari Traa Rose Half-Zip||$120||Heavyweight||100% merino wool||240||7.6 oz.|
|Helly Hansen Lifa Stripe Crew||$45||Lightweight||100% polypropylene||125||3.5 oz.|
|Arc’teryx Rho Crew Neck LS||$110||Midweight||84% polyester, 16% elastane||190||5.6 oz.|
|Smartwool Classic All-Season||$90||Light/midweight||88% merino wool, 12% nylon||150||4.7 oz.|
|Patagonia Capilene Thermal Crew||$119||Lightweight||92% polyester, 8% spandex||129||6 oz.|
|Icebreaker 200 ZoneKnit Crew||$150||Midweight||100% merino||200||7.4 oz.|
|Black Diamond Solution 150||$135||Light/midweight||78% merino, 22% polyester||150||5.2 oz.|
|Ortovox 185 Rock'N'Wool LS||$110||Midweight||100% merino wool||185||5.7 oz.|
|REI Merino 185 Half-Zip||$90||Midweight||100% merino wool||185||Unavail.|
- Baselayer Warmth Categories
- Materials: Merino Wool and Synthetics
- Fabric Weight (g/m²)
- Odor Prevention
- Crew Neck vs. Quarter or Half Zips
- Baselayer Fit
- Key Baselayer Features
- Baselayer Care
- Other Baselayers: T-Shirts, Tanks, and Bottoms
- Layering Systems
When searching for the right baselayer, one of the most important considerations is warmth. Do you need thin and breathable insulation for shoulder season running, or a cozy and thick long-sleeve for deep-winter resort skiing? To help with your search, we've broken down our picks into three categories—lightweight, midweight, and heavyweight. In assigning these categories, we take into account the baselayers' materials and fabric weight, in addition to our own testing experience.
Logically, lightweight baselayers are the best breathers but do the least toward keeping you warm, making them ideal for spring skiing, bluebird days, and high-output activities such as nordic skiing and cold-weather running. That said, even thin merino wool baselayers can be very warm for their weight, so you’ll want to keep this in mind depending on your use (we found the 180-g Ridge Merino Aspect to be much too warm for ski touring). What’s more, the thinner the merino, the less durable it becomes; for this reason, most lightweight baselayers are made of polyester. One of our favorite lightweight offerings is the Outdoor Research Echo Hoodie, which we’ll even wear as a sun protection shirt during the summer months. If you’re looking for mid-winter warmth, it’s worth bumping up to a midweight baselayer.
For the widest variety of conditions, a midweight baselayer makes the most sense. It will provide the warmth you need yet still breathe well enough for physical exertion, especially when made with high-quality merino or polyester. Midweight baselayers are the most popular choice for downhill skiers: They’re plenty warm for the lift ride up but won’t cause you to overheat on the descent. They are less popular than lightweight baselayers for hiking or ski touring in moderate conditions, as the extra warmth corresponds with a drop in the fabric’s ability to regulate temperatures (even midweight merino can get too hot in warm temperatures). But in cool spring and fall conditions, a midweight baselayer can perform great as an outer layer and is the ideal next-to-skin piece for resort skiing on cold days.
Heavyweight baselayers are purpose-built for use in cold temperatures or if you’ll be relatively sedentary. The extra thickness inhibits breathability, and it’s easy to work up a sweat even on short walks. Keep in mind that you don’t need all of your insulation from a single article of clothing, and as a result, you can always add warmer layers on top of a light or midweight baselayer. But for deep-winter resort skiing, extreme cold, or low-output activities around camp, a heavyweight baselayer can be the height of coziness. If you do go this route, we love designs like the Smartwool Classic Thermal and Kari Traa Rose Half-Zip.
Merino wool is our favorite baselayer material for winter use: It’s ultra soft and incredibly warm for the weight, offers great temperature regulation, and resists odor far better than synthetic materials. For a warm and cozy next-to-skin layer that doesn’t clam up, it’s a great choice. However, merino wool baselayers are less durable than the synthetic competition, especially thin varieties or those that aren’t blended with other materials like polyester or nylon (for example, the Smartwool Classic All-Season is 88% merino wool and 12% nylon). They’re also too warm for mild conditions and intense activity like ski touring, running, and nordic skiing, and absorb sweat more than synthetics (which isn’t great news once you cool down). But for mellow days out or if you really prefer the feel of natural material, merino has a lot to offer. For more information about its pros and cons, check out our article: Merino Wool: Is It Worth It?
Synthetic materials like nylon and polyester are a cost-effective alternative to merino, and excel in terms of moisture wicking and durability. For shoulder-season conditions, high-output activities, or use as an outer layer (as in the case of a layer like the NW Alpine Spider Hoody), they’re our first choice. The largest downside to synthetics is stink build-up; despite efforts from manufacturers, odor-resistant polyesters and nylons still can’t compete with the natural benefits of merino (although they are improving). In addition, synthetics don’t provide as much warmth for the weight, and as such are not our first choice in truly frigid conditions or for low-intensity activity. It’s also worth noting that they range a great deal in terms of quality: The Arc’teryx Rho Crew Neck LS uses a really high-end polyester material, while the Patagonia Capilene series is more prone to pilling and snagging.
It’s not quite as simple as deciding between an all-merino or all-synthetic baselayer. Some brands use blends that aim to offer the comfort and performance of merino wool alongside the durability and moisture-wicking of polyester/nylon. We often see this in lightweight varieties: NuYarn (as seen in the Black Diamond Solution 150) wraps merino fibers around a nylon core, and then weaves this manufactured thread together with polyester. It’s worth being cautious with 100% merino—unless the fabric weight is around 200 grams per square meter (or more), pure merino wool will form holes fairly quickly.
Manufacturers list the weight of a baselayer's fabric in terms of grams per square meter (g/m², or GSM), which provides a good idea of how much warmth the baselayer will provide. From our picks above, these weights range from 120 grams per square meter for the The North Face Summit Pro 120 to 250 grams per square meter for the Smartwool Classic Thermal 1/4 Zip (keep in mind that not every manufacturer reports this spec). On the low end, the Summit Pro is a great pairing for mild conditions and high-output activities, while offerings like the Classic Thermal will be overkill for everything but deep winter. It's important to note that fabric weight does not always perfectly align with warmth, due to variations in fit and material (1-g merino wool generally offers more warmth than 1-g polyester). For example, we've found the 240-gram Kari Traa Rose to be much warmer than the 250-gram Smartwool Classic Thermal.
The breathability of a baselayer is dependent on a number of factors, including the type and quality of the fabric, thickness, and openness of the weave. In general, lightweight merino wool and synthetic baselayers (like the Outdoor Research Echo) offer better breathability than heavier-weight offerings. But between the two materials, synthetics are by far the more breathable choice: While merino does a great job pulling moisture away from your skin, it has a tendency to hold on to it. We’ve also found that merino is simply too warm for most intense activities. As a result, synthetic baselayers are our go-to for mild conditions or when we anticipate building a sweat (think ski touring, nordic skiing, and running). And it’s worth mentioning that there are a few merino offerings that we’ve found to be serviceable, particularly those with mesh panels in high-heat areas (like the Smartwool Intraknit Active or Icebreaker 125 ZoneKnit).
Blends: Very good
Merino wool excels at pulling moisture away from your skin, and less sweat buildup means less stink. If you’re taking an extended backcountry trip and don’t want to carry multiple baselayers or rinse them each night, merino is the way to go. Some synthetics do fine at fending off odor, provided you aren’t working up a huge sweat. For example, we’ve hiked for extended periods in Patagonia’s Capilene Midweight in cool weather and have been impressed with its odor resistance. But nothing beats merino in keeping you dry and stink-free.
Merino: Very good
Synthetics: Not good
Here is where the tide changes: Merino is super soft but prone to developing small holes over time that eventually hamper the performance of the product, whereas synthetics should last for multiple seasons. To put this in perspective, we usually get a season or two out of a standard lightweight merino baselayer, even from the top brands and by following their washing instructions (cold water and line dry). Admittedly, these shirts get a lot of use, but that’s still a very short lifespan. But with synthetics, one or two seasons would be on the short end of the spectrum, and we would hope for three or four.
Some companies are blending wool and synthetics to increase the strength of the baselayer without compromising next-to-skin comfort, and overall results have been positive. We haven’t noticed much of a drop in terms of comfort or performance, but merino/synthetic blends are a step up in durability. Even so, if we’re wearing a baselayer without anything overtop, we’ll always opt for a fully synthetic piece such as the NW Alpine Black Spider Hoody.
Blends: Very good
Merino: Not good
Nearly every baselayer on the market is offered in several styles, including long-sleeve crew and half/quarter-length zippered shirts. Many women opt for a crewneck style to minimize bulk, but there are several reasons to consider a zippered shirt. One upside is the ability to adapt to changing weather conditions: You can zip up for added warmth at the start of the day and unzip as you work up a sweat. And if you want to remove the shirt altogether, it’s nice not having to take off your helmet to do so. Additionally, the extra coverage you get with the raised collar is a nice boost in warmth, and we’ve even found that many quarter- or half-zip long sleeves wear decently well around town too. The downside is that the collar can flop around if you unzip the shirt while running, and having a zipper on your next-to-skin layer isn’t as comfortable as the cleaner crew style (especially when adding multiple layers overtop).
For optimal performance, baselayers need to have a snug fit. This helps the fabrics draw moisture away from your skin most efficiently. Some women like wearing their baselayers for casual use, and that’s when dedicated performance designs like the Smartwool Intraknit Thermal and Icebreaker Oasis 200 are less useful. These shirts conform to your body like performance pieces should but are far too tight to wear anywhere else. REI’s Merino 185 Long-Sleeve Half-Zip and Patagonia’s Capilene Thermal Crew are on the opposite end of the spectrum, with roomier fits (especially around the torso) that sacrifice a little in moisture wicking and breathability but have added casual appeal. In the end, your decision is a personal one, and we recommend looking at fit based on intended use and preferences on style.
Baselayers can range from simple, featureless crew tops like the Patagonia Capilene Midweight Crew to hooded half-zips with a chest pocket (the NW Alpine Black Spider Hoody, for example). If you know you’ll be layering a mid or outer layer over your baselayer, the simpler the better. However, those who wear their baselayer as an outer layer will appreciate zip pockets and thumb loops. And climbers and skiers will benefit from a tight hood or balaclava that fits under their helmet (the Patagonia Capilene Air’s scuba-style hood is one of our all-time favorites). Some baselayers even have the capability of blocking sun rays (measured by the UPF rating). As usual, it will help to identify what you’ll be using your baselayer for before determining what features you need.
Caring properly for your baselayers can go a long way toward maximizing their lifespan, especially if you opt for an all-merino design. As with most wool products, we recommend washing merino baselayers in cold water and line drying. Directions vary by manufacturer—some may claim that merino can be machine-dried, but we’ve found this can result in premature pilling and unwanted shrinkage. Another consideration is thickness: Thinner baselayers like the Smartwool Classic All-Season tend to break down quicker than thicker designs like their Classic Thermal, especially in high-wear areas like the cuffs and shoulders. Lastly, synthetics typically require less maintenance—just throw them in with your other laundry—but we’ve never felt overburdened by taking a little more care with our merino layers.
The focus on sustainability has been increasing in the outdoor industry over the past several years, and baselayers are no exception. In this category, there currently are two key trends: responsibly sourced wool and the use of recycled synthetic materials. The former indicates that sheep were treated humanely and in accordance with strict animal welfare and environmental standards (there are a number of certifications, including the Responsible Wool Standard and ZQ-certified wool). We’ve also begun to see more companies utilizing recycled materials, which cuts down on fossil fuel consumption and reduces the amount of plastics being produced overall (Patagonia's Capilene Midweight is made from 100% recycled polyester). All in all, we appreciate these efforts and are eager to see more brands come on board.
Baselayer T-Shirts and Tank Tops
Our list above comprises long-sleeve baselayers, but many of the designs are also sold in T-shirt and/or tank top variations for warm-weather activities like backpacking and hiking. Apart from the inherent differences in warmth and coverage, T-shirts and tanks are generally cheaper since they utilize less material. For example, the Smartwool Classic All-Season Long-Sleeve costs $90, while the T-Shirt is $80.
In the end, a final decision will come down to preferences on warmth, coverage, and styling. The consensus among our female editorial staff is that short sleeves and tanks are the preferred option in the summer and shoulder seasons, especially for movement-dependent activities like running and climbing. If the temperature drops, you can simply add a light layer overtop. Long sleeves are a nice alternative for those who want added sun protection and coverage, but the boost in warmth can be a downside on truly hot and exposed days, even if you opt for a thinner design.
Most baselayers on this list have matching bottoms with the same construction that are available at a similar or identical price point. For brevity’s sake, we list the tops here as they are more popular, but the bottoms are readily available and share the same pros and cons. However, generally speaking, maintaining a warm core will do much more for your entire body’s comfort than keeping your legs warm. But given that there’s no need to choose—and provided that almost nothing is cozier than a pair of long johns—we’re huge proponents of quality baselayer bottoms as well.
To get the most out of your technical clothing, it’s important to think of everything as a system. Each piece relies on the layers around it to perform well. As an example, if you have a baselayer that wicks moisture well but are wearing a fully rubber mid or outer layer, it won’t matter how nice of a merino fabric you have: You’ll still be wet and miserable. As such, take the time to put together mid and outer layers that are as high-performing as the baselayers listed above.
Baselayers serve two primary purposes: To keep you warm and to wick moisture. Whether constructed with wool, synthetic material, or a blend, a baselayer is made to retain your body’s heat while moving moisture (i.e., sweat) away from the skin. And it’s important to note that these functions work together—keeping your body dry will in turn lead to more warmth. They can be worn underneath a midlayer or shell during the winter months or as an outer layer during the fall and spring for activities like hiking, biking, and climbing. The thickness and material of your baselayer will heavily impact warmth and breathability, so make sure to keep this in mind when making a purchase. If you’re still on the fence about which option is best for you, we’ve broken down all of the key considerations in our article: How to Choose Baselayers.
For high-output activities like hiking, backpacking and climbing, breathability is top priority. We recommend a fleece jacket or synthetic jacket for balancing warmth and ventilation. High performers include the Arc’teryx Atom LT and the R line of fleeces from Patagonia (including the R1 Air Zip-Neck). If you only plan to grab your insulating layer during downtimes, such as hanging around camp after the sun goes down, consider a warm and super packable down jacket. Skiing is a similar story, and conditions will dictate the best midlayer for you. Options can range from a puffy down jacket to a light fleece.
Outer layers are the most specialized part of the system, and their complex designs can get quite pricey. A waterproof, breathable, and packable rain jacket is needed for activities like climbing and hiking/backpacking. Winter conditions are much harsher, so durability takes precedence for ski jackets. These designs offer more pockets for storing gear or personal belongings and a longer fit to protect you from snow sneaking through. There are also hardshell jackets that blur the lines, mixing the weight of a rain jacket with the performance (and extra cost) of a ski jacket.
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