The Best Base Layers for Men of 2026

The Quick & Dirty: A Nuyarn merino blend that feels weightless while providing surprising warmth and durability. It’s a versatile set that excels at moisture management, but isn’t immune to snags and tears.

Newly updated, the Ibex Woolies Pro Tech ($120 each for top and bottom) has been reinforced with a touch of nylon to ensure these base layers maximize the incredible qualities of merino wool. The previous Woolies layers were our best overall pick in previous years, and after an entire year of solid use, we’re confident that this revised set still holds the title.

The fabric blend is now an 85% merino wool drafted around a 15% nylon core, and spun with a method known as Nuyarn, which doesn’t introduce any twist as the loom unifies the two materials. This material tweak may seem small, but it greatly increased the durability of merino wool, and certainly so in ultralight 125 g/m² layers such as these. Ibex claims an 8.8x increase in durability, and while we can’t quite quantify that, the Woolies Pro layers do feel a bit tougher, especially when stretched.

We wore these base layers while backpacking across the Pacific Northwest this summer, but the greatest test came when we took the set to Alaska for an 8-day bushwhack deep into the Brooks Range. This trip demanded lightweight gear, but also a set of sacred base layers we could deploy after getting soaked while packrafting in Arctic rivers. The Woolies Pro Tech set fit the bill perfectly, and came back from the trip without a hole or loose stitch.

Merino wool makes the most sense in base layers, where you’re looking for some supplemental warmth in the layer. Synthetic cuts are better for active pursuits where you’ll need to move moisture out of them (for that, consider the Summit Series Pro 120 layers from The North Face). It makes sense that we enjoyed these base layers the most when breaking them out to sleep in during backpacking.

The price tag on the merino wool kit is always going to be a bit higher than synthetic options, and these Ibex layers are no exception at $120 a piece. The Ridge Merino Aspect Base Layers offer a better value in merino wool, with a nearly identical fabric blend to the Woolies Pro Tech ($95 for the top, $75 for the 3/4-length bottoms). However, the super lightweight feel of the Woolies Pro pushes them to the top of the list. The 125 g/m² feels like wearing nothing, and it’s exactly what we’re after when crawling into our sleeping bags.

The Quick & Dirty: A no-frills synthetic set that offers impressive stretch and knit construction for under $30. It won’t win any warmth awards, but it wicks sweat effectively for high-energy activities.

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 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.

The Quick & Dirty: The industry benchmark for 100% merino performance, this midweight set is incredibly soft, naturally odor-resistant, and significantly warmer than lighter blends. It’s a plush choice for deep winter conditions.

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 its 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). Contributing editor Steve Grapel has 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 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 the same price. 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.

The Quick & Dirty: A synthetic classic that uses a diamond-grid interior to trap heat. The added HeiQ Mint treatment keeps the typical synthetic stink at bay, but the layers will accumulate pilling with use.

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 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.

The Quick & Dirty: Stylish enough to wear alone as a standalone shirt, but function as a high-performance winter running thermal. We did find the low-profile pockets a bit small.

While many winter layers struggle to balance insulation with the high-output demands of sub-freezing miles, the Arc’teryx Rho LT Base Layers ($120 top; $100 bottom) hit the sweet spot for the dedicated winter runner. Expertly patterned and sewn with the anatomical precision Arc’teryx is known for, these layers offer a streamlined fit that moves effortlessly during a stride, making them the most capable cold-weather aerobic sets in our guide.

The Rho LT Zip Neck top is a standout for temperature regulation. During testing on frigid morning loops, the tall collar provided immediate protection against the wind, while the deep chest zip allowed us to dump heat instantly as heart rates climbed. This design is far more functional for running than a full hood, which can often bounce or feel cumbersome at pace.

One of the most unique features is the addition of laminated pockets on the chest and thigh. While these are often buried under shells in other sports, they are game-changers for winter runners. When worn solo or under a light vest, they provide the perfect, bounce-free spot to stow a car key, an energy gel, or essential lip balm, which is a utility rarely seen in a standard base layer.

The Torrent 190 fabric has a super-soft brushed interior that feels incredible against the skin, rivaling the comfort of high-end merino. With 16% elastane, the mobility is exceptional, and whether sprinting on flat tarmac or navigating icy trail switchbacks, the fabric never restricted movement. While it offers significant warmth, the moisture-wicking properties kept us from feeling swampy during high-intensity efforts.

The price point is certainly a premium, but the Rho LT earns its keep through sheer versatility. It’s a specialized piece of running gear that is equally at home as a thermal layer for a hut-to-hut ski tour or as a stylish, standalone piece for a post-run coffee. If you only invest in the top, you’ll still find it becomes the most frequently used item in your winter wardrobe.

The Quick & Dirty: Offering close performance to high-end blends at a fraction of the cost, this merino-nylon set provides excellent durability and warmth. The 3/4-length bottoms are standout for ski boot compatibility.

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 ($95 for the balaclava top; $75 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.

The Quick & Dirty: A unique, mesh-style construction that creates massive air pockets to trap heat. It looks unconventional, but for expedition-level warmth, its thermal efficiency is unmatched.

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 it’s 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 overall). When investing in equipment for high latitudes or long trips abroad, spending the extra money makes good sense to us in the long run. The Thermo Base Layers from Brynje are made for your next far-flung expedition.

The Quick & Dirty: Utilizing a unique weave to maximize airflow, these are some of the most breathable synthetic layers on the market. The tradeoff for weighing next-to-nothing is limited insulation.

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 ($100 top; $110 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 $210 for the full set, the Summit Series Pro Base Layers aren’t the cheapest, but we think they’re head and shoulders above 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.

The Quick & Dirty: A 100% merino baselayer that gets the full measure of wool warmth and damp-resistance, but also wears out faster (and smells a little more) because of it.

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 ($120 for the top; $120 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 Quick & Dirty: A ski-friendly merino blend that has an excellent feel, but the patterning still needs to be ironed out.

We’ve spent years swapping between scratchy wool and clammy synthetics, yet the Le Bent Featherweight Baselayers ($170 for the top; $133 for the bottom) manage to disappear on the body. It’s thin, airy, and has a silken hand-feel that makes typical 100% merino layers feel rugged in comparison.

Testing took us from the wind-scoured ridges of the Mt. Baker backcountry to high-speed laps at Stevens Pass, providing a broad look at the fabric’s thermal range. During high-output splitboard touring, the breathability was top-tier. The balance of 60% merino wool to 25% bamboo and 15% nylon in the Nuyarn blend makes for a moisture-resistant wear, and enhances durability.

In the resort, the Featherweights functioned as a great second skin under a mid-layer fleece. Even during a physical day of plowing through some Cascade concrete, the fabric didn’t bunch or chafe. If you’re a high-heart-rate adventurer, this is the moisture-wicking sweet spot you’ve been looking for.

However, the fit isn’t without its quirks, particularly for those of us with longer wingspans. While the torso length is generous enough to stay tucked into a bib, we found the sleeves to be noticeably short. During aggressive riding or when reaching to adjust bindings, the cuffs consistently migrated toward the mid-forearm. This ride-up created an annoying gap between gloves and sleeves.

This sleeve-length issue is a blemish on an otherwise stellar athletic cut. While the 4-way stretch is impressive, it doesn’t quite compensate for the lack of raw fabric length in the arms. If you have shorter arms, this might be a non-issue, but for the lanky crowd, it’s a factor that keeps the Featherweights just shy of perfection.

The Quick & Dirty: A lightweight merino-polyester hybrid that balances the odor control of wool with the fast-drying durability of synthetic fibers. It’s a jack-of-all-trades, master-of-none.

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 of this base layer, 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, such as 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.

The Quick & Dirty: Premium 100% merino base layer set that is very cozy to slip into — if you can manage the price tag.

The WoolX Explorer Top ($140) and Backcountry Leggings ($150) are premium base layers with a price tag to match. But once you’re deep in the wilderness, it’s tough to find fault with their performance. These 100% Australian merino wool layers come from a brand that takes the material seriously. Tester Nick Belcaster put the set through a rigorous winter in the North Cascades, where they served well during backcountry ski tours, rugged hiking, and multi-day snow camping.

Unlike many base layer tops that end abruptly at the wrist or rely on finicky thumbholes, the arms of the Explorer Top are deliberately elongated. This extra length allows you to roll up the cuffs to create a snug, secure anchor during active pursuits or unroll them to tuck your digits inside for a boost of warmth while transitioning at a windy col.

The 230 g/m² fabric weight puts these layers squarely in the midweight thermal category. This density makes them the sweet spot for truly cold-weather active use or as a dedicated sleeping set in the backcountry. While they might be a bit too robust for high-output spring missions, they provide a level of set-it-and-forget-it warmth that is hard to beat when temperatures dip into the single digits.

In terms of fit, the WoolX set leans into a relaxed, athletic silhouette that avoids the compression common in synthetic alternatives. The Explorer Top offers a generous torso length that stays tucked into your waistband, even during high-reach movements. This roomier cut also facilitates better airflow between the wool fibers and your skin — the secret to its superior thermoregulation. The Backcountry Leggings follow suit with a non-restrictive fit through the thighs and a wide, soft waistband that doesn’t dig in during long days in the skin track.

For the athlete who demands the natural odor resistance and thermoregulation of pure wool without synthetic blends, the Explorer set is a top-tier investment. If you are looking for a mostly-merino set that is lighter for high-aerobic days, the Ibex Woolies Pro Tech is another versatile option to consider.

The Quick & Dirty: A premium, high-warmth option that looks as good at the bar as it performs on the skin track. You’ll spend more to get them as a trade-off.

While the brand calls these midweight, we’d argue that the supple 280 g/m² Stio Basis PeakWool Midweight Base Layers ($149 top; $149 bottom) are closer to heavyweights, but that’s not a bad thing. These tops and bottoms feel nearer kin 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 $149 per piece, but that’s due 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.

The Quick & Dirty: A high-durability hunting essential that survives the thickest brush without sacrificing thermal performance. A bit more expensive than similar sets, as you’re paying for camo patterns.

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, 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.