The Best Base Layers for Men of 2025

High-quality base layers can get pretty expensive — and many people are hesitant to pay top dollar for clothing that no one else will ever see. With that said, there are some great budget options on the market too, such as this nifty set of MEETYOO Men’s Thermal Underwear ($29). For less than half of the price of many of the base layer tops on this list, this set is perfectly suited for active use in mild to moderate winter conditions.

Made from a knitted polyester and spandex blend, these tops and bottoms definitely fit into the “lightweight” category. This knitted construction is similar to that seen in other high-end layers like the Smartwool Intraknit or Brynje Thermo Base Layer, and creates a garment with almost no seams to chafe on and an impressive built-in stretch. While you shouldn’t expect a ton of warmth and heat retention from these, they do provide a layer of simple comfort without restricting mobility.

In warm conditions, we found these base layers capable of wicking sweat without becoming wet and saturated. They’re breathable, too, which is much appreciated on the approach trail or the skin track. The 100% synthetic build is to be expected at the price point, and while the stink factor did build up quicker than most we tested, you won’t be wearing any holes in these layers prematurely.

Though the no-frills (note: no relief fly on these bottoms) Men’s Thermal Underwear lacks the high-tech materials and long-term durability of some other options on this list, they’re effective, simple, and fairly priced. Buy them and run them into the ground — they’re cheap enough.

For warmer conditions and quicker-paced activities, you don’t need too much in the base layer department to stay toasty warm, and The North Face Summit Series Pro 120 Base Layers ($90 top; $100 bottom) are just about the best lightweight options we’ve tested to date. At 132 g/m², they’re fairly airy and are only made lighter by a unique fabric construction.

This ‘DotKnit’ fabric weaves hundreds of holes across the face of these base layer tops and bottoms, and whether we wore them underneath a simple shell or layered beneath a full set of fleeces, the added breathability was noticeable. Our testing on these layers occurred through the beginning of winter in the Pacific Northwest, where temperatures are mild and good moisture management is key.

The cut on the Summit Series base layers is semi-fitted, with a slight drape that tucks under layers quite well. The stitching is all low-profile and didn’t rub when worn underneath pack straps. An articulated cut kept the hem from rising too much when reaching overhead, and the thumb loops helped avoid the dreaded glove-to-sleeve air gap.

These base layers won’t be the best cold-weather sleepwear as they aren’t the warmest when worn solo. That said, they do make great layers to keep a sleeping bag clean when the conditions are a bit more temperate. Like most synthetic base layers, you’ll need to contend with the eventual funk, which will eventually overwhelm even the best anti-odor treatment.

At $190 for the full set, the Summit Series Pro Base Layers aren’t the cheapest, but we think they’re head and shoulders above than most of the other lightweight layers on the market. Many of these are too light for their own good and give up durability to do it. These layers, thankfully, don’t have that problem.

It’s the little things with Patagonia’s Capilene Midweight Base Layers ($89 each for top and bottom) that elevate them to our top award in the synthetic — yet stink-free — base layer category. The smooth external face slides easily under another layer. On the inside, a diamond grid pattern adds a little stretch and micro pockets to trap heat and wick moisture away.

On the top, two elastic thumb loops keep the sleeves down when overlaying a heavier base without adding bulky material around the wrist. And when you’re done for the day, hang it at the lodge from the cord sewn into the back. These synthetic baselayers benefit from an antimicrobial treatment in the same way that many baselayers do, but this is the name-brand stuff: HeiQ Mint — which adds an herb-derived treatment.

In practice, we noticed that this treatment isn’t quite as good as the original HeiQ silver-salt formula, but still much better than untreated synthetics after a hard day sweating into them. We’ll leave the change on the table for the planet here. Other appreciated aspects of Capilene baselayers are the raglan sleeves on the top, which eliminate seam lines atop the shoulders (and keep them away from pack straps).

The equally comfortable bottoms are pleasantly form-fitting and exceptionally stretchy. They are a bit looser-fitting than some other base layer bottoms we tested and land about in the middle between the pajama-like Ibex Woolies and skin-tight Icebreaker Oasis. The broad elastic waistband kept these pants where they belonged all day.

While the price of these base layers has gone up $10 each since we first started testing them, Patagonia’s steadfast Ironclad Guarantee makes them still an easy buy. Repairs needed due to wear and tear can be made at a reasonable charge, which isn’t something nearly any other baselayer manufacturer offers. One of our editors has used the same Capilene shirt for nearly 30 years, and it’s still going strong — these base layers live up to the hype.

A good base layer will keep you warm and dry. A great base layer will do it year after year and across a wide range of activities. We found ourselves reaching for the Ridge Merino Aspect Base Layers ($90 for the balaclava top; $60 for the 3/4 bottoms) both on and off the trail, but for ski-touring more than anything else.

Backcountry skiing is demanding on layering systems, and that all starts at the base layers. With its slightly relaxed fit and contrasting fitted sleeves, the Aspect’s techie details are subtle. The 18.5-micron wool is woven with a touch of synthetic. This boosts wool’s natural odor-resisting and sun protection properties but has the added benefit of durability and stretch provided by synthetics.

Flat-locked seams are sewn offset from the shoulder. This allows a pack’s shoulder straps to ride comfortably, minimizing any chafing. We also loved the top’s hidden horizontal thumb loops. They tuck away cleanly into the shirt’s cuff, and bridge the gap between sleeve and gloves perfectly. Finally, the true cherry on top: the balaclava hood that seals out errant cold wind and snow.

The base layer bottoms are available in a 3/4 length, making them ideal for pairing with ski or snowboard boots and avoiding the awkward bunching of extra material. While these pieces are a good price for merino wool, it should be noted that they will begin to accumulate holes as you wear them. That’s just the name of the game when wearing high-performance yet natural materials.

The Ridge Merino Aspect layers easily do double duty when worn for a variety of winter activities, but we think they excel when worn for skiing.

Like the Ibex Woolies, the Arc’teryx Rho LT Base Layers ($120 top; $100 bottom) lean into the fashionable camp, and we think they’re just about the best-looking sets out there to wear on their own. Expertly patterned and sewn with noticeably more care than most base layers, this set is the one you’ll catch us wearing around the cabin.

Like most Arc’teryx kit, there’s a dizzying number of sub-variations of these base layers, but we think the ‘LT’ cuts are the best of the bunch and the most versatile. The Rho LT Zip Neck top sports a tall collar that immediately set itself apart in our testing, and we found it added a good amount of warmth without the addition of a full hood that some manufacturers incorporate.

Keeping up with the trend, there’s a laminated pocket on the front of the chest and along the side of the thigh on the bottoms — features we’ve hardly ever seen in a base layer. The utility is fairly limited when the layers are buried, but when worn solo, they’re the perfect place to stow a car key or some essential lip balm.

The ‘Torrent 190’ material sports a super-soft brushed interior that makes these layers rival even Merino wool options, and while they’re a little too warm for high-output activities, we found them great for slower-paced days. The 16% elastane kept them moving with us when we tested them during a hut-to-hut ski tour in British Columbia, with the added bonus of being casual enough to wear around the hut after hours.

The price is something to contend with, but considering the double duty these baselayers can do, it helps ease the sting a bit. Even if you just snag the top, you’ll undoubtedly get plenty of use out of it.

Mesh base layers have gone far and wide on some pretty harrowing expeditions, and the Brynje Thermo Base Layers ($105 each for top and bottom) were there from the start. Tenzing and Sir Edmund sported a cotton version of the mesh base layers when they stood atop Everest for the first confirmed summit, and these merino wool blend versions are even better.

Sure, the look is strange, but the performance tells the whole story: The fishnet-like weave captures warmth between the holes in the fabric excellently while still allowing for vapor transfer when sweating heavily. The result is a baselayer that might have a fabric weight of only 125 g/m², but insulates much more like the heavyweights in our review.

We took these base layers well out of their comfort zone, as well, challenging them to a 300-mile bikepacking trip that ran headlong into wind and rain, where they still excelled — even outside of their element. The party stopped around the time the sun came out, however, as the black color warmed up quicker than we could shed warmth. But as a layer that’ll be beneath others most of the time, this should be a non-issue.

One thing to know about mesh base layers like these: you’ll want to be in good company should you decide to strip down to them when the mercury climbs. While the Women’s ‘Super’ Thermo (that is, 100% polypropylene) does incorporate a few solid modesty panels, the unisex merino cut does not, making these ideal layers for running when its cold enough to stay bundled up.

The price is also a bit high, but not as high as the Kora heavyweight combo we’ve recommended (and also quite a bit lighter weight overall). When investing in equipment for high latitudes or long trips abroad, spending the extra makes good sense to us in the long run. The Thermo Base Layers from Brynje are made for your next far-flung expedition.

Wool is a magical fiber; it doesn’t hold a stench, naturally blocks harmful UV rays, and is prized for its ability to stay warm when wet. Near the top of the stack of merino sits Icebreaker. The stalwart brand has converted synthetic enthusiasts into dyed-in-the-wool fans. And we can’t stop wearing the Icebreaker Merino Oasis 200 ($115 for the top, $105 for the bottoms).

Subtle details make the 200 a great choice for buyers looking at wool for the first time. The 200-weight fiber straddles the line between lightweight and midweight, which matches the lux merino fiber’s ability to adapt to the climate. This is a 100% merino set, which means that a) you’ll certainly pay for it, and b) it’ll need a gentler hand in use and washing.

The fit is slim but doesn’t bind or compress. Flat-locked seams are sewn out of the way. Gusseted arms allow full articulation of the torso, and the cuffs at the wrists are minimal. The shirt doesn’t have thumb loops — a notable omission that keeps it from getting our full support over other layers like the Ibex Woolies or Patagonia Capilene layers — but the material is so smooth it easily slides under another layer.

The Oasis is intended to be worn next to the skin and layered over. The slim fit reinforces this. And when things heat up, we love the top’s half-zip that drops to the middle of the chest. It allows more temperature regulation than quarter-length zipper tops that are on the market. And when you want that extra level of protection, the front zips up comfortably like a turtle neck.

Wool tends to be more delicate and can wear out more quickly than a synthetic top like Patagonia’s Capilene Midweights. But if you’ve got the dough and want the full measure of advantages that merino brings to the table, the merino Oasis 200 set is a good bet.

The Outdoor Research Alpine Onset Merino 150 Base Layers ($119 top; $99 bottom) are another merino wool base layer set, except these are a blend, with a large percentage of polyester and Lycra added in. The roughly 50/50 split means that the typical benefits of merino are blunted a bit, but the trade-off is in durability.

The 150-weight Alpine Onset layers are great all-arounders, and while they don’t stand out too much in any one metric, sometimes flying under the radar is a good thing. We tested them across the board on hikes and days at the ski resort alike and found solid performance, with a particular highlight being the three-panel balaclava hood.

Also of note is the 30 UPF rating this base layer sports, meaning it’ll lend some additional protection over the more gossamer tops on the list. The pants also boast this rating, and though it’s less likely you’d be galavanting around in them solo, we appreciate the thoroughness in rating them. The waistband of these base layer bottoms is comfortably broad and rode well under pretty much everything we wore on top of them.

Ultimately, the price is a bit much for us to recommend wholeheartedly (as you can get better Merino blends for less money, like the Ridge Merino sets). The flip side is this: if you’re after Merino but can’t stand the early retirement that high-percentage pieces tend to render, the Alpine Onset set can make a good deal of sense.

While the brand calls these midweight, we’d argue that the supple 280 g/m² Stio Basis PeakWool Midweight Base Layers ($139 top; $139 bottom) are closer to heavyweights — but that’s not a bad thing. These tops and bottoms feel closer to pajamas than pretty much anything else we’ve worn recently, and during a weeks-long cold snap, we practically lived in the set.

They’re undeniably pricey at $139 for either piece, but that’s owed to the fabric Stio has labored over for these base layers. ‘PeakWool’ is a multi-faceted blend of a majority merino wool, combined with TENCEL (a rugged plant fiber), recycled + virgin nylon, and a touch of spandex for stretch. The result is a supremely smooth weave that shows little wear.

A highlight of the base layer bottoms is the unique relief flap orientation (don’t say we aren’t thorough in our testing), making trailside bathroom breaks as simple as possible. The downside to the thicker material is that the seams tend to pile up where they bring material together, and while the raglan sleeves keep a seam from the center of the shoulders, one a bit lower on the back does rub a bit beneath a pack, we found.

Safe to say, these base layers work best for sleeping or lounging, but they excel in their lane. When stacked up side-by-side with other more casual layers, we gave the edge to the Arc’teryx Rho LT Base Layers, due in most part to their better seams and slightly more versatile weight. For long weekends tucked away in the cabin, however, it’s tough to go wrong with the Stio layers.

At $270, the Kora Xenolith Yak & Merino Wool Mountain Sweater 2.0 represents the upper end of the base layer price range. But a little backstory helps take the edge off. Kora sources its yak wool directly from Himalayan farms, and farm-to-fashion isn’t cheap, but you can feel good knowing your purchase helps support a small community halfway around the globe.

At first blush, the Xenolith seems like a straightforward, heavyweight top with a deep front zipper, much like the Icebreaker Merino Oasis or Smartwool Classic. The labeling is discreet, and the stitching is appropriately positioned. But what elevates it to the top of our list is the fabric: a yak-merino wool blend.

Yak wool is uber fine and has a hollow core, making it soft to the touch while boosting warmth (air, trapped in the wool’s hollow core, has fantastic insulative properties). The Xenolith is spun with a merino blend. The result is plush and surprisingly stout, but we recommend layering it under a protective shell for activities that have the potential for high abrasion.

Turn it inside out, and you’ll see a mesh liner padding the back and shoulders. Look closer, and you’ll notice it protects a thin layer of Polartec Alpha. Alpha lofts up like down, trapping heat and wicking moisture. Because it’s synthetic, it stays warm when wet.

You might think the Alpha liner would make the back a little sweaty while schlepping a load in warmer temps. It’s actually thinner than the double wool layered in front. A thinner layer of wool lines the lower arms. The Xenolith smartly fits like an insulated vest with integrated sleeves.

Yes, this top is over the top for backpacking. But that’s not what it’s made for. Think high-altitude mountaineering, ice climbing, downhill skiing — the Xenolith finds its groove in pursuing activity in the dead of winter. If you’re looking for an alpine-weight base layer (and your card can carry the price), the Xenolith is the best you can buy.

Let’s give a shout-out to our hunters. They spend hours — if not days — quietly waiting in what can be atrocious conditions. The SITKA Gear Core Merino 220 Base Layers ($199 for the top, $129 for the bottoms) are an excellent layering foundation for the fall’s fickle weather.

While SITKA takes aim at the hunting market with its garments, there’s a lot of greatness that spills over into other activities. And we found the Core Base layers to be a wonderful addition to our year-round kit.

The lightweight ArmorSpun merino wool is airy and breathable, preventing odor buildup. This is nice not only for your hunting partner but also for keeping your profile low on hunts. The material has a smooth face, and the arms of the top are finished with thumb loops that make it easy to layer over.

We’re not generally fans of chest pockets on base layer tops (as they tend to become buried under other layers), but the inclusion here makes a bit more sense for the sport-specific SITKA layers.

True to the name, the Core base layers help to effectively maintain a comfortable core temperature. These midweight layers are ideal for spring and fall tasks and serve as a solid foundation for trips that dip into winter.

The high price here is due to the high-percentage merino weave, but also the fact that you can get the SITKA base layers in a variety of Optifade camouflage patterns — which take a surprising amount of R&D to create. If you’re not a hunter, SITKA offers the Core Merino 220 base layers in a solid grey Lead colorway.

These base layers are pretty niche for hunting use (scope our selection of best Hunting Base Layers while you’re here), which keeps them from reaching the top of our lineup, but if that’s your jam, it’s tough to go wrong. We see great utility in snagging a baselayer that matches the camo pattern you’ve invested in.

Comfort-wise, you won’t find anything smoother than Ortovox’s Rock’n’Wool Base Layers ($110 for the top and bottoms). These form-fitted beauties are spun from a 19-micron Tasmanian merino wool. Luxuriously soft to the touch, they fit like a dream.

On the top ($110), the hem runs appropriately long, tucking cleanly away in ski pants or bibs, and wears untucked equally well. Both the top and bottoms ($110) function as an extension of the body, which is really what we look for when playing hard outside.

We like that the top’s tapering sleeves narrow down the arms to the wrists with just enough stretch to pull over the forearms if you want. The asymmetric offset sleeve design adds a nice touch of flair.

Straddling lightweight and midweight, the Rock’n’Wool material has a wide thermal range, wearing comfortably next to skin in summer or integrated into your winter layering system.

The Rock’n’Wool Top is one of the best-fitting and softest shirts on the list. We almost awarded this shirt our overall best base layer, but a few minor things knocked it off the podium. Without thumbholes, the sleeves can pull up when donning a second layer.

The seams aren’t flat-locked, and the torso panels connect on top of the shoulder, which ride dead center under pack straps. And the asymmetric sleeve design on the left sleeve, while cool-looking, slightly binds around the elbow when pulling it over the arms. And we find 100% wool less durable than fabrics woven with a touch of synthetic.

Aside from the slightly funky seams, the bottoms are near-perfect. The Rock’n’Wool Base Layers have become one of our go-to’s for resort skiing.

Smartwool shares the podium with Icebreaker in terms of quality merino wool. Smartwool’s 250-weight base layer is tried-and-true and has spawned lots of variations in their lineup, including crew neck and hoodie variations.

All of the brand’s base layer offerings are fantastic, but we’ve found that year after year, the one we reach for most is the Smartwool Classic 250 Merino Thermals ($120 for the top, $115 for the bottoms). Our editors have used these for over 3 years as a foundation for cold-weather fishing, backpacking, and general outdoor pursuits.

The half-zip top is particularly excellent. As the day goes on and the sun begins to warm things up, we find the zipper allows us to dump heat to keep us cool. The 10″ zipper length isn’t quite as long as the Kora Xenolith or SITKA Core 220 layers, but it still does an admirable job of cooling the brakes.

Like all genuine merino wool, these base layers aren’t cheap. Plus, they’re fairly delicate. You need to pay special attention to maintaining your investment. For most folks, we tend to recommend the more durable Ibex Woolies as they’ve got a bit of nylon and are just a bit cheaper. You’ll miss out on the quarter-zip on the top, however, and if the added venting option appeals to you, the Classic 250 layers can be a great option.