The Best Base Layers for Men of 2024-2025

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 L.L.Bean Lightweight Base Layers ($40 each for top and bottom) is a fitted base layer system that’s been treated with an antimicrobial finish — a necessity, in our opinion. This gives it a longer shelf life in your wardrobe. It doesn’t skimp on technical details, either — these base layers could have easily also garnered a ‘Best Value’ nod as well.

At 130 g/m², these base layers are squarely in the lightweight camp, and are best for shoulder season forays or high-output activities where heavier layers might trap extra warmth. The Patagonia Capielene Midweight layers are a bit thicker, so if you’re on the fence and feel these might not be warm enough, it’s an easy pivot to make.

The seams are flat-locked and offset, helping them ride more comfortably under a pack. On the crewneck top, a pair of thumb loops keep the sleeves down when you decide to layer over it, which it does without any awkward binding or seam rub. Plus, the crewneck top doubles as a nice-fitting shirt for all-season use.

The base layer bottoms are equally well made, and sport a wide stretch waistband that keeps them from creeping down during repetitive activities like skiing moguls or chopping firewood. We found L.L.Bean’s lightweight Base Layers to offer big value for a lightweight base layer set, and we recommend them for folks on a budget.

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 the Helly Hansen 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.

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.

With low-profile seams and a reinforced crotch panel, the Yushu bottoms are thoughtfully designed without feeling over complicated. Though they do breathe well, we recommend saving these exclusively for the coldest days of the year. The yak wool is super warm, and can cause sweating issues during truly active use.

Interestingly, Kora flips the blend on these bottoms, where the Xenolith uses more Merino wool, and the Freedoms use more yak. This makes good sense to us, as bottoms typically don’t require the added moisture management of tops, and the added yak wool only increases the cozy feel.

Paired with the Kora Xenolith Mountain Sweater, the Yushu Yak Wool base layer bottoms are a fit for folks brave enough to venture out into sub-zero wind chill. If you’re headed into unkind elements and plan on really moving, however (a ski across Greenland?), a mesh baselayer like the Brynje Thermos may be a better choice. But for static warmth, the Kora combo is our choice.

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.

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.

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.

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 our go-to for resort skiing.

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 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.

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. On the shirt, the torso is reasonably longer, adding coverage without draping obnoxiously.

We also loved the top’s hidden horizontal thumb loops. They tuck away cleanly into the shirt’s cuff, making them less visible when wearing it around town. The bottoms are simple and effective.

The Ridge Merino Aspect layers easily transition to suit an active lifestyle, blending work, workouts, parenting, and chores. For the price, they’re tough to beat.