Quick heads-up: some of the links on this page are affiliate links. If you make a purchase through them, we may earn a small commission (at no extra cost to you). This small bit of income helps keep our site running.
Best Long Underwear for Men of 2023
This post was last updated on December 06, 2023.
Looking for the Women's version of this post? We've got you covered: Best Long Underwear for Women of 2023
On those chilling nights under the stars or frosty mornings raised in high-altitude trails, a reliable long underwear can be a game-changer. The comfort and warmth it brings make it a vital cog in your camping, backpacking, or climbing gear. We have been in your boots and assessed countless long underwear options to bring you the finest of them - the Smartwool Merino 250 Base Layer Bottoms.
Regarded as the undisputed champion in its class, the Smartwool Merino 250 Base Layer Bottoms ticks all the boxes. From its exceptional moisture-wicking ability to its comfortable yet stylish fit, this long underwear stands atop above its competitors. Not to mention, its fabric, durability, and odor resistance are all top-notch. It's no wonder it has won our hearts as the best long underwear for men.
But the universe of long underwear doesn't end here. In this review, we have also identified two fantastic runners-up and a stellar budget-friendly option. Each product has been evaluated on the same rigorous criteria to ensure fairness. We also encourage you to browse our other reviews on men's down jackets, down pants and fleece jackets to complete your winter-wonderland kit. So, let's get started and help you discover your ideal long underwear solution.
Our Top Recommendations
Our Top Pick
Smartwool Merino 250 Base Layer Bottoms
The Smartwool Merino 250 Base Layer Bottoms come out on top owing to their unrivaled warmth and comfort, with numerous reviewers particularly praising how well they manage moisture and reduce odor, even after multiple days of hiking.
Runner Up #1
Arc'teryx Men's Rho LT Bottom
The Arc'teryx Men's Rho LT Bottoms nab the top spot thanks to consistently stellar user reviews praising their exceptional warmth-to-weight ratio and exceptional breathability, making them an ideal pick for chilly outdoor excursions.
Runner Up #2
Patagonia Capilene Air Bottoms
Patagonia's Capilene Air Bottoms clinch the top pick runner-up spot due to their unmatched breathability and comfort, effortlessly wicking away sweat while maintaining an ideal body temperature, as users rave in reviews.
What you should look for
(and what we test for)
Fit
Opt for a snug fit that comfortably hugs your body, as this reduces the risk of chafing during prolonged physical activities, while also ensuring that your body heat is well-retained.
Weight
Consider the weight of the underwear; light or mid-weight options are great for moderate activities, but if you're hitting the slopes or involved in high-altitude climbing, you may need heavyweight long underwear for extra warmth.
Material
Choose a material that can wick away sweat and keep you dry, like Merino wool or synthetic fibers, as these will keep you warm even when wet and won't hold onto unpleasant smells.
Breathability
Ensure your selection has excellent breathability to regulate body temperature and prevent overheating during strenuous activities, which can be determined by the fabric used and the inclusion of ventilation panels in the design.
Smartwool Merino 250 Base Layer Bottoms
$100.00The Best Men's Long Underwear
Based on our research and testing, we think the Smartwool Merino 250 Base Layer Bottoms is the best Men's Long Underwear on the market right now, for anyone looking to play hard outside.
Reasons to Buy
- Soft and comfortable merino wool material
- Keeps user warm in low temperatures
- Moisture-wicking capabilities
- Odor-resistant compared to other base layers
- Top-notch breathability allowing good ventilation
Reasons to Avoid
- Somewhat expensive relative to other base layers
- May feel a bit tight for some users
- Durability reported as lower compared to synthetic layers
The Important Specs
- Inseam: Usually around 29 inches, depends on size
- Material: 100% Merino wool
- Fabric Weight: 250g/m²
Review Roundup
The Smartwool Merino 250 Base Layer Bottoms have been impressing those in the camping, backpacking, and climbing communities for quite some time now. This solid set of long underwear has garnered a good reputation for a few key factors.
One of the most consistently praised features is the superior warmth these provide. Made from 100% Merino wool, you can count on a cozy and comfortable fit even on the coldest of hiking trails. Many customers have reported that these are ideal in winter weather conditions, providing just the right amount of insulation and warmth.
Yet it's not just the warmth these bottoms dish out that's got everyone talking. They're also applauded for their comfort, largely attributed to the interlock knit style used in their construction. This allows for a certain level of stretch and flexibility, perfect for those more challenging climbs.
Customers have also highlighted the base layer's excellent moisture management. Whether you're on a long trek or pushing yourself on a climb, sweat can be an unavoidable consequence. However, the Smartwool Merino 250 Base Layer Bottoms are designed to wick away moisture effectively, keeping you dry and enhancing your overall comfort experience.
While generally considered a top-notch choice, they're not without the occasional criticism. For instance, some customers have raised concerns over the sizing and recommended checking the size guide carefully before purchase. Others weren't thrilled with the price tag, viewing these bottoms as a little on the expensive side.
But all in all, the Smartwool Merino 250 Base Layer Bottoms continue to dominate the long underwear game. The combination of warmth, comfort, and superb moisture management often outweigh the few criticisms. Users have shared time and again how much they appreciate having these in their backpack on chilly adventures, and how they have become a key component of their outdoor kit.
Comfort
Users typically note how comfortable these bottoms are. The soft merino wool is often highlighted for preventing any itchiness one might get from lower-quality wool base layers.
Durability
The longevity of this product is somewhat contested. Some users reported the bottoms to become a bit threadbare after consistent use, so their durability can't necessarily be compared with synthetic fabric alternatives.
Fit & Layering Compatibility
While some folks found the fit a tad snug, most consumers find the Smartwool Merino 250 Base Layer Bottoms nicely fitting for layering purposes. The bottoms can be layered easily underneath other clothing for extra warmth.
Material
The 100% Merino wool material stands out for its comfort and warmth. It's also noted for providing a softer touch as opposed to some other wool products that can feel scratchy against the skin.
Moisture-Wicking & Breathability
Based on customer feedback, the Smartwool Merino 250 Base Layer Bottoms are adept at wicking away moisture from the skin. Combined with its high breathability, it helps keep users dry, even during intense physical activities in the cold.
Odor Resistance
The Smartwool Merino 250 Base Layer Bottoms have received high marks for their odor-resistance. Multiple day users, on camping for example, found them to resist building up any unpleasant smells compared to other materials.
Value
Though they come with a higher price tag, many buyers believe it's worth the extra bucks given the overall warmth, comfort and odor-resistance. They've proven themselves to be a go-to base layer for those willing to invest in quality winter comfort.
Warmth-to-Weight Ratio
Though these aren't the lightest base layer on the market, users often highlight the impressive warmth they offer. This warmth-to-weight ratio makes them a popular choice among those needing to stay warm in frigid conditions without immense bulk.
Prices
Arc'teryx Men's Rho LT Bottom
$100.00Runner Up
Based on our research and testing, we think the Arc'teryx Men's Rho LT Bottom is a great choice if you're looking for a men's long underwear to go play hard outside with, if our top pick isn't quite what you're looking for.
Reasons to Buy
- Comfortable fit with strong elasticity
- Excellent warmth-to-weight ratio
- Durable with reinforced stitching
- Superior moisture-wicking and breathability
- Great odor resistance
Reasons to Avoid
- Costlier than comparable options
- Not the most stylish design
- May not be ideal for extreme cold
The Important Specs
- Care: Machine Washable
- Fabric: 84% Polyester, 16% Elastane
- Length: Full-Length
- Waistband: Brushed Elastic
Review Roundup
Arc'teryx Men's Rho LT Bottom is a solid option for anyone seeking long underwear that marries both comfort and performance. Made to insulate and regulate body temperature, these bottoms are a crowd-pleaser among outdoor enthusiasts, climbers and hiker types alike.
Right off the bat, reviewers love the snug, warm fit that the Rho LT Bottom offers. Thanks to the Torrent polyester and elastane blend material, these bottoms are both stretchy and breathable; an important combo for all-day wear during a range of activities.
Many folks online have praised the design and fit of the Men's Rho LT Bottom. Users noted that unlike other long underwear, they don't ride up or bunch, but fit snugly around the leg and give a seamless look under pants. It's a detail many customers appreciated and often referred to as a 'great fit.'
Described as 'lightweight', but not skimpy on the heat, the Arc'teryx Men's Rho LT Bottom has been praised for its thermal capabilities. Reviewers shared their experiences of weathering even the most bone-chilling temperatures in these - a testament to the quality Arc'teryx promises.
One drawback some reviews mentioned is the product's price point. It's a bit on the higher end compared to others in the market. But a large chunk of users say it's a worthy investment for the warmth, comfort, and durability the Rho LT Bottom provides.
In terms of maintenance, reviewers found these bottoms easy to clean - they're machine washable and dry quickly. However, a few users observed that they may pill slightly after frequent washing.
Another positive aspect users often commented on is the odor-resistance of these bottoms. According to multiple reviews, the Rho LT Bottom seems to keep the 'stink factor' at bay, even after a few days of wear, which is definitely a big plus for multi-day hikers.
All-in-all, the Arc'teryx Men's Rho LT Bottom comes highly recommended by many customers for its comfort, insulation, and quality. But keep in mind the slightly higher price tag and potential for minor pilling with frequent laundering.
Comfort
Customers rave about the Arc'teryx Rho LT Bottom's comfort. It has a soft, brushed interior that feels pleasant against the skin, and the stretchy material moves with your body without rolling or bunching.
Durability
Made with elastic Lycra fibers, this long underwear is designed for long-term use. Reinforced stitching ensures that the bottoms hold up well, regardless of the adventure.
Fit & Layering Compatibility
The Arc'teryx Rho LT Bottom offers a slim fit without restricting mobility, making it ideal for layering during cold weather. The elastic waistband sits comfortably on your hips and doesn't pinch or bind.
Material
The fabric blend of polyester and elastane strikes a perfect balance between comfort and durability. The poly blend retains heat well, while the elastane allows for stretch and movement.
Moisture-Wicking & Breathability
The Arc'teryx Men's Rho LT Bottom excels in handling sweat and keeping you dry and comfortable. The efficient moisture-wicking feature disperses sweat across the fabric, encouraging quick evaporation. The breathable fabric prevents overheating and maintains a balanced body temperature.
Odor Resistance
The fabric has built-in antimicrobial properties that help deter odor buildup, allowing for multiple uses between washes—a handy feature for extended backpacking trips.
Value
While on the pricier end, this long underwear's superior performance and longevity render it a good investment for avid outdoor enthusiasts. The combination of comfort, durability, and functional features means you're paying for a premium product that holds up.
Warmth-to-Weight Ratio
Despite being lightweight, these bottoms provide substantial warmth, making them suitable for a variety of climates and activities. They aren't, however, built for extreme cold, so you may want to consider additional layering in harsher weather.
Prices
Patagonia Capilene Air Bottoms
$139.00Runner Up
Based on our research and testing, we think the Patagonia Capilene Air Bottoms is a great choice if you're looking for a men's long underwear to go play hard outside with, if our top pick isn't quite what you're looking for.
Reasons to Buy
- Superior warmth
- Excellent breathability
- Functionally stretchy
- Sustainable materials
Reasons to Avoid
- On the pricier side
- Not as durable with heavy use
The Important Specs
- Design: Seamless 3-D construction
- Material: 51% merino wool and 49% recycled polyester
- Environmentally Friendly: Patagonia's commitment to sustainable materials
Review Roundup
The Patagonia Capilene Air Bottoms deserve recognition as a top-notch choice for men's long underwear. These bottoms are truly in a league of their own in terms of both comfort and functionality. Made from an innovative blend of recycled polyester and merino wool-based yarn, they're designed to be soft, warm, and breathable. They're an environmentally-friendly option for the more conscious consumer.
When it comes to warmth, numerous customer reviews highlight their effectiveness even in bone-chilling temperatures, beating some of the heftier options hands down. Their sleek, lightweight design coupled with their powerful insulation stake their claim as a strong competitor to your traditional, chunkier long johns.
Talking about breathable/ventilation properties, buyers frequently mentioned their quick-drying capabilities. Sweat doesn't stand a chance, being quickly whisked away from your skin, helping maintain a dry and comfortable base layer even during strenuous activities. Also worth mentioning is the nature-centric pattern, loved by many for bringing a touch of style to their outdoor gear.
Furthermore, customers love the stretchiness you get with these bottoms. Whether you're hiking, climbing, or lounging by the campfire, it's clear this balanced elasticity, backed up by numerous reviews, not only provides freedom of movement but also ensures a form-fitting shape after repeated use.
However, every product has its downsides and the Patagonia Capilene Air Bottoms are no exception. Although the breathability and thermal capacity are praised, several customers have indicated a small snag - these capilene bottoms aren't the best performers in terms of toughness. Some users noticed minor wear and tear issues after extensive use, especially in high friction areas.
Another common issue mentioned by customers pertains to the price tag. These bottoms are indeed not the most budget-friendly option out there. However, many of those who took the plunge vouched for the quality and overall performance, stating they were worth every penny.
In terms of sizing, opinions vary. Some find that these bottoms run slightly larger than expected, while others find them true to their size. It seems a good idea to try these on before making a purchasing decision, if possible.
Comfort
Many users have expressed love for the cozy comfort these bottoms provide. The seamless 3-D construction eliminates common chafe points, creating a more comfortable wearing experience. The blend of merino wool and recycled polyester also creates a soft, next-to-skin feel.
Durability
Though built with high-quality materials, some customers have noted a slight decrease in durability with heavy use, particularly in high-friction areas. However, for regular use, the Capilene Air Bottoms hold up quite well.
Fit & Layering Compatibility
Customer reviews indicate these bottoms have a snug fit without being restrictive, which is a big plus for comfort. Their slim profile also makes them an ideal base layer, fitting nicely under heavier layers without causing discomfort or restrictiveness.
Material
The combination of merino wool and recycled polyester contributes not only to their comfort and performance but also to their sustainability — an important factor for many environmentally conscious consumers.
Moisture-Wicking & Breathability
Users have consistently praised the Capilene Air Bottoms for their moisture-wicking capabilities and breathability. The merino wool blend works overtime to pull sweat away from the skin, keeping you dry during vigorous activities. The breathability is also noteworthy, allowing for efficient temperature regulation even in changing weather.
Odor Resistance
Thanks to the incorporation of merino wool, the Capilene Air Bottoms seem to help limit odor buildup from extended use. Most users mention that they didn't have to worry about them starting to smell on multi-day trips.
Value
While these bottoms come with a steeper price tag compared to some others, most customers have agreed that the performance, comfort, and warmth they offer makes them worth the investment. If budget isn't a main concern for you, you'll find good value in these bottoms.
Warmth-to-Weight Ratio
The Patagonia Capilene Air Bottoms score highly on the warmth-to-weight ratio. Despite being relatively lightweight, these bottoms provide incredible warmth, suitable for cold weather camping or hiking. This makes them a snug companion that won't put extra bulk in your backpack.
Prices
REI Co-op Midweight Bottoms
$54.95Best Budget Men's Long Underwear
Based on our research and testing, we think the REI Co-op Midweight Bottoms is a great pick if you're looking for a men's long underwear that is more budget friendly, without sacrificing too much in quality.
Reasons to Buy
- Affordable price
- Good warmth-to-weight ratio
- Effective moisture wicking
- Odor resistance
Reasons to Avoid
- Not the most durable
- Fit might be too loose for some
The Important Specs
- Material: 92% polyester, 8% spandex
- Washing Mode: Machine wash
- Colors Available: Black, gray, navy
Review Roundup
The REI Co-op Midweight Bottoms are a popular choice for many outdoor enthusiasts looking for a budget-friendly option without skimping on functionality. As their name suggests, these bottoms are midweight, making them versatile for various weather conditions; from chillier morning hikes to comfortable wear under a pair of ski pants.
This product has a user-friendly blend of polyester and elastane that provides a nice balance between warmth, breathability and elasticity. Due to their stretchiness, users have appreciated the close but comfortable fit that doesn't hinder movement on long treks or intense climbs.
One thing that's been praised by many customers is the design of these bottoms. Featuring flatlock seams, these reduce chafing which can be a real nuisance on more extended trips. The waistband is also comfortable and doesn't dig in, an attribute appreciated by individuals with varying waist sizes.
In terms of durability, these bottoms seem to hold up pretty well. Users have mentioned that after several washes the fabric retains its shape, while the waistband and ankles maintain their elasticity. However, some have mentioned mild pilling in areas of high friction over time.
On the downside, some customers have noted that the REI Co-op Midweight Bottoms run a bit long, which could be a hurdle for shorter individuals. And while they’ve received positive feedback on their thermal capabilities, they might not provide enough insulation for extreme cold conditions.
In the end, the REI Co-op Midweight Bottoms stand out as worthwhile for their cozy fit and affordability. Despite a few minor faults, they remain a resounding favourite among outdoor adventurers on a budget.
Comfort
Comfort is one of their strong suits. The REI Co-op Midweight Bottoms feel soft against the skin and are stretchy enough to move with you, whether you’re walking, running, or climbing.
Durability
They are fairly durable for the price point. However, some customers have noted that after several washes they start to show signs of wear and tear.
Fit & Layering Compatibility
The REI Co-op Midweight have a loose fit, which is great for comfort but might not be the best for those who prefer a tighter fit. They are stretchy and layer well under clothes without much bulk.
Material
The fabric composition includes 92% polyester and 8% spandex, offering a blend of stretch, comfort, and moisture-wicking performance.
Moisture-Wicking & Breathability
The REI Co-op Midweight Bottoms are known for effectively wicking away sweat, making them a great choice for high-intensity activities. They're highly breathable, users say they never feel stuffy or overly heated while wearing them.
Odor Resistance
They offer decent odor resistance, especially if you're going to be out for shorter trips. For longer adventures, regular washing is advisory.
Value
Offering a good balance of performance and affordability, the REI Co-op Midweight Bottoms are an excellent value. They perform fairly well across most categories and remain an affordable pick for budget-conscious shoppers.
Warmth-to-Weight Ratio
Despite being light, these underwear punch above their weight when it comes to warmth. They provide ample insulation for cold weather. However, they fall slightly behind heavy-weight underwear in extreme cold.
Prices
Related Posts
Best Hiking Pants for Men of 2023
Whether you're taking a leisurely stroll in the woods or tackling a challenging mountain climb, your hiking pants can make or break your experience. It's not just about comfort. The right pair of...
Best Hiking Socks for Men of 2023
Embarking on a thrilling hiking adventure always demands sturdy, durable and comfortable gear. The clothes may change with the season and specific needs, but one essential piece of equipment...
Best Down Pants for Men of 2023
There's nothing quite like hitting the trails for some backcountry adventuring, but when it comes to gearing up for colder months, you'll want the perfect gear that's equal parts warm, packable,...
Best Base Layers for Men of 2023
When it comes to embarking on your epic outdoor escapades, one can't underestimate the power of a killer base layer. This isn't about being flashy. No, a base layer is all about function over...
Best Fleece Jackets for Men of 2023
When it comes to staying warm while enjoying your favorite outdoor activities, a solid fleece jacket is a must-have. These versatile jackets can double as layers for chilly campfires or serve as...
Best Down Jackets for Men of 2023
Whether you're a seasoned camper, an enthusiastic backpacker, or an adrenaline-driven climber, the right down jacket can be your best ally in maneuvering harsh weather. Enter, the men's Mountain...