5 Best Long Johns of 2023 | Men’s Thermals
Having thermal underwear means comfort when it’s achingly cold. In the skiing and camping world, the word has long been out regarding the importance of a well-realized layering system to stay warm. Long Johns, your next-to-skin layer, are the essential “base” upon which you’ll build your clothing kit.
Being the bottom portion of your ensemble, thermal underwear–or long johns–is less essential to your keeping warm than a dedicated base layer “top”. They are used supplementarily in the event of serious cold, or for tactical layering purposes.
Below we’ll cover our top picks for your base layer bottoms, across a wide range of styles and purposes.
For more on how to figure out what thickness, material, and price point are right for you–check out our buyer’s guide below.
The Top 5 Long Johns in 2023
1Best Technical Layer: Icebreaker Merino 260 Tech Leggings
2Best Lightweight Bottoms: Smartwool Merino 150 Base Layer Bottoms
3Best Every Day Bottoms: Patagonia Capilene Midweight Base Layer Bottoms
4Best for Running: REI Co-op Lightweight Base Layer Bottoms
5Best Budget Bottoms: Carhartt Base Force Heavyweight Bottom
All the Long Johns We've tested
Warm, wooly, and wicking–IceBreaker’s Tech Leggings are built for hard work in cold weather.
These plush, 100% merino tights offer all of the technical benefits desirable in a cold weather base layer (insulation, moisture control and breathability), while retaining the flexibility and range of motion that you would need during demanding winter sports.
You can rest easy about all the sheep shorn to stitch them together as well, IceBreaker is a leader in sustainably and ethically sourced wool.
As is always the case, the only downside of merino is how quickly it breaks down compared to synthetics.
But in the case of Icebreaker, we’re assuming you’re after the best and warmest option to tackle some specific objectives over the span of a few seasons rather than a lifetime pair of long johns.
It’s also worth noting that you should be prepared to pay premium money for the premium benefits they offer.
Specs & Features
- Slim Fit build, low rise crotch
- True 100% merino build
- Gusseted build for increased mobility
- Flatlock stitching to prevent chafing
Our Overall Review
We have thoroughly tested - and read reviews from other experts and users. In summary, this is what we think:
Things we like:
Great balance between warmth and breathability for frigid temperatures
Retains a good amount of flex and movement for being entirely thick wool
Just about the best that can be bought
Things we don't like:
- Merino tights are destined to break down
- They’re more expensive than anything else on this list
Where to buy:
What are “Long Johns”
Long underwear, colloquially known as “long johns” are the bottom component of what is now referred to as a “base layer”.
For the better part of the last 4 centuries, peoples have depended upon long johns when the mercury starts to fall, be that as loungewear around the house or worn underneath other garments in a more active environment.
The name “long john” is supposedly a reference to the late 18th century heavyweight boxing legend John L. Sullivan, who favored wearing them in the ring.
While the jury is out on their martial applications, long johns are moisture wicking to keep you comfortable during similar, high-exertion activities, in the same way that ski socks pull moisture from your feet when jammed into the sweaty confines of an alpine boot.
High-grade base layers should simultaneously provide enough warmth in frigid temperatures, while staying dry and airy despite heavy sweating.
Why use long underwear?
When most people talk about thermal base layers, they’re primarily referring to the “tops” worn around the torso. This base layer anchors the top, under the ski jacket for skiing or snowboarding or hiking, etc.
In terms of insulation, it’s much more effective to tackle the chest and abdomen initially to keep your core body temperature up. Though it’s definitely worth mentioning that the large muscle groups in your legs can extrude some serious heat during exercise, potentially adding to a pair of thermal underwear’s effectiveness.
Ranging from long hours of stillness in the treestand to demanding mines on the nordic track, thermal underwear are widely applicable to a slough of comfort-minded and technical scenarios. From our standpoint long johns are best used in three circumstances–in the event of excessively cold temperatures, long-term low-exertion cold exposure, and underneath uninsulated shells or other technical layers.
Like many other warmth-graded garments, long johns and base layers at large exist on a insulation-to-breathability continuum. Different “weights” (referring among other things, to the thickness of the material) are used in different circumstances, and the distinction is largely up to your personal preferences.
Long johns and by extension, other base layer categories, almost always have their fabric weight rating listed somewhere. The categories might not be hard-cut but are a dependable place to start your search barring no strong specific preference.
Below we’ll delve into the three weight grades of long johns and their main circumstantial applications, but first we’ll cover the two primary factors you should consider when deciding on a pair.
- XC skiing
- Backcountry touring
- Ice climbing
- Alpine skiing
- Mild winter hikes
- Ice fishing
- Winter camping
- Extreme cold
Lightweight long johns are best applied in moderate temperatures or during high-exertion activities like running, backpacking, or XC skiing.
As the name implies, they’re thinner and less bulky than comparable categories of thermal underwear, this allows them to both breathe and wick away moisture more efficiently than their mid and heavyweight counterparts.
Another less intuitive benefit of lightweight long johns is their ability to be efficiently layered. This puts them in close competition with midweight options in terms of versatility, particularly when it comes to more demanding aerobic activities. Worn under a pair of shorts they’re perfect for a winter run, or underneath your snow pants for a demanding climb up the skin track.
Keep in mind that there are some drawbacks that come with low weight, the pretty obvious lowered capacity for warmth as well far less durability.
Midweight long johns tend to be a bit more limited by both hard work and warm temperatures, but they aren’t totally out of the question for more mild activities like snowshoeing or alpine skiing when the weather is a little colder.
You might opt for midweight long johns as something to wear around the fire when fall camping. Patagonia Capilene is a great thermal underwear for this.
Not quite as light or layerable as the diminutive lightweight category, they’re nonetheless still a fine choice underneath uninsulated snow pants or a waterproof shell when you’re out and about.
They’ll also hold up to extended wear and the occasional snag much better than lightweight options.
On the far end of the spectrum, heavyweight long johns are thick, uncompromising base layers best reserved for frigid temperatures or any situation where you anticipate standing or sitting around in the cold for an extended period of time.
Because of their extreme insulative properties, these thermal underwear won’t breathe at all, and any amount of prolonged exertion is likely to result in an uncomfortable sweaty mess.
You can’t go wrong with the Icebreakers for this. The more affordable option for a durable and active outdoor need will also be satisfied by the Base Force long underwear by Carhartt. But as noted the latter aren’t as warm.
These may be your best option if you’re looking for something to lounge in, what immediately comes to mind is sitting on the sidelines of a football field in late October, long after the sun has set.
On the extreme end of both ends of the spectrum, you have outliers that cater to more specialty applications. Featherweight base layers are almost exclusively used for distance runners in need of something to keep off late year chill and biting winds, but still keep them dry and unencumbered.
Similar to lightweight thermal underwear they’re more subject to wear and tear from time and the occasional snag.
Expedition weight base layers are the warmest available, and as the name implies are intended for use in extreme conditions. They’re best for stop and go activities where you expect some exertion followed by an extended break, consistent movement might be more of an issue given their reduced aptitude for ventilation and moisture wicking.
As is the case with any piece of insulative clothing, exertion has a massive impact on internal temperature during use. In the case of thermal underwear and thermal base layer as a whole, it’s no stretch to say “you get out of it what you put into it.”
If you’re working hard enough, you can get by in freezing temperatures with minimal layering, and are often better off doing so to prevent overheating, soaking through your layers, leading to hypothermia when the pace slows. By that same token, if you’re on a snowmobile, ice fishing, or contending with late fall chill in the stands of a sports match, you’ll be better served by something thicker and more insulative. Icebreakers come to mind here.
Concerns regarding outside temperature, in some ways, are still guided by how you’re exerting yourself. You tend to be much more resilient to the cold if you’re working hard, and likely to cool off considerably as soon as you stop charging. These concerns aside, there’s no doubt that the demands you put on your gear scale consistently with how cold it is outside.
Keep in mind that your base layer and long johns are only one part of your insulation system. Particularly when it comes to extended adventure-based travel, versatility should be your top priority. It’s much more valuable to have a midlayer and outer shell that can be depended upon than a pair of too-warm long johns that you’ll suffer in.
Outside of the fabric weight, the materials themselves are going to have the biggest performance impact on your thermal underwear. The materials are much the same as any you would find in outdoor wear, with the exception of cotton and silk, though it should be noted that cotton base layers aren’t suitable for any kind of high output outdoor activity but is included on this list for being a comfortable and affordable alternative in terms of being an effective insulator.
There’s no understating Merino wool’s impact in the outdoor industry, it’s by and large the favorite for most next-to-skin layers from socks to beanies. Merino wool long johns are great for all the same reasons that Merino wool makes a great base layer otherwise–it’s comfortable, breathable, odor resistant, and most importantly: warm and moisture wicking.
There’s a reason that there are so many die-hard merino fanatics out there, and a reason why merino tends to be on the upper end of the price spectrum in all applications.Pros
- Top of the pack breathability and moisture wicking ability
- Warmer than most other materials per weight
- Antibacterial and odor-resistant
- Much less durable than synthetics
- More expensive than any other material on the market
Polyester and Other Synthetics
Synthetics cover a wide range of materials from lycra to polyester, and are an affordable alternative to wool for any kind of outdoor application. Synthetics have the edge in terms of both their quick-drying quality and comparative durability when measured against natural fibers.
As mentioned above, while synthetics tend to be more affordable and durable than merino, they don’t insulate as well and lack the odor-resistant qualities beloved in merino.
- Quick-dry capability superior to merino
- Comparable performance at a lower cost
- More durable than natural textiles
- No antibacterial or odor-preventative properties
- Less warm than merino or blends
Synthetics cover a wide range of materials from lycra to polyester, and are often blended with wool to create a hybrid with the warmth and odor resistant benefits that natural fibers offer, with some of the increased resilience and quick-drying aspects present in synthetics.
Bringing a “best of both worlds” attitude to the table, blends tend to be among the most expensive and performance oriented options out there.Pros
- Superior performance for technical applications
- Nearly as durable as pure synthetic options
- Retains some of the antibacterial benefits we love in merino
- Often more expensive than even 100% Merino wool
- Approaches but does not fully capitalize on the true benefits of both wool and synthetics
Silk is a little anachronistic compared to some of the flashy and fine tuned options that you see on this list, but it still has the advantage of being just about the most comfortable next-to-skin layer you can find. It’s also reasonably warm and odor-resistant. But that’s where most of the appeal stops- outside of use as a sleep layer there are much more practical and affordable options in synthetics.Pros
- Just about as comfortable as it gets next to skin
- Reasonable performance compared to more contemporary materials
- Fairly warm per weight of the material
- Mediocre performance wise compared to merino and synthetic analogues
- The least durable material used in thermal underwear
Cotton is not an acceptable material to use for any kind of strenuous outdoor activity, when wet it loses its insulative properties and actually makes you colder as the material chills. However, for those in search of a cheap and warm pair of long johns to wear around the cabin or at most shoveling a few inches of snow off of the driveway, it can provide a means of staying warm without investing much more than you’d pay for a cotton t-shirt.Pros
- Affordable and warm when it’s dry
- Not acceptable in any strenuous circumstances
- Makes you colder when it’s wet
When we’re talking about long johns, we’re talking about a next to skin layer. It follows that your long johns will do their job more efficiently scaling with the amount of material that is actually touching your skin. Having a snug, consistent fit will help your long johns both keep you insulated and more importantly, wick away any moisture clinging to your skin.
Snug but comfortable is the key in this circumstance, while it’s important to maximize skin contact, you don’t want to be uncomfortable. Do your best to avoid any loose fitting garments, as these have the tendency to let moisture pool up and accumulate rather than dissipating as intended.
Long johns and base layer bottoms are generally only used when a shirt or top isn’t enough to get the job done. As such, warmth may be one of the factors that you want to highlight, as opposed to emphasizing breathability or moisture regulation. Both fabric weight and material are going to impact the warmth of your thermal underwear.
While it’s fairly intuitive to gauge fabric weight with warmth, here’s a brief ranking of the different materials in order of most to least insulative.
- 100% Merino
- Wool and Synthetic Blends
- Silk & Synthetics
Breathability and Moisture Control
The main job of any base layer is to keep you dry when sweat starts to build up. As as such, it’s one of the key factors you want to consider when deciding on your base layer bottoms.
As is the case with warmth, the breathability and moisture-wicking properties of your long johns are directly related to their thickness in a way that doesn’t merit much explanation beyond the thicker they are, the less effective they will breathe and release built-up moisture from their core.
Lightweight thermal underwear as a rule will always be more effective at keeping you cool and dry than anything heavy.
Beyond this, any difference is strictly material–and different textiles will have different performance impacts based on their inherent qualities.
We’ll quickly run down the list of different fabrics in order of the most breathable to the least. Breathability and Moisture Wicking
- Merino Wool
- Synthetic and Wool Blends
As is the case with warm, breathability and moisture wicking properties, durability is largely related to both the fabric weight and the materials that go into the thermal underwear. It stands to reason that thicker garments will be a bit more durable, but the relationship between thick fabric and durability isn’t nearly as cut and dry as it is with warmth.
Namely in the case of merino, which has the tendency to break down after extended use regardless of exposure to sharp sticks and rocks and the like. Synthetic and wool blends see a big uptick in resilience, but if you’re looking for the longest shelf life, nothing really does the job like a real synthetic.
Below we’ll rank our fabrics in order of most to least durable.
- Wool and Synthetic Blends
There’s quite a bit of disparity between the prices of these long underwear. Some super-tuned synthetic and wool options are expensive enough to balk at.
How much you want to invest in a pair of long johns is mainly concerned with the kinds of things that you’ll be doing in them. Unless you’re planning on doing some mountaineering or are an avid cold-weather sports enthusiast, there’s no reason to empty your wallet over a pair of tech-specced long johns.
In many ways Merino is the highest quality option, tending to really drive the price up–it has the unfortunate consequence of also being among the least durable of the fabrics.
As skiers and snowboarders, we can’t deny the quality of merino, as well their effectiveness even when slightly moist from sweat. For hiking too, they’re a proven commodity.
But, again, they’re not going to last as long as synthetics.
Synthetics can double your value, being much less expensive and the most resilient out of all your options.
Frequently asked questions
Long johns (or base layer bottoms) come in all shapes and sizes, and the best one is going to depend on what qualities you want to emphasize. To learn more about long johns and their many varieties, take a look at our buyer’s guide and best of list for all the details on the best of the best. In the meantime, here’s a short list of some of our favorites.
Best thermal underwear
Long johns, thermal underwear, or base layer bottoms are thermal underwear worn for two purposes–to keep you warm, and to keep you dry. They probably got their name from the boxer John L. Sullivan who wore them in the ring.
Long johns come in many variations for a wide range of purposes anywhere from expeditionary mountain climbing to watching a late fall football game.
To learn more about thermal underwear and how to choose the best pair for you, take a look at our buyer’s guide for all of the details, and our top picks across the different categories.
Women’s base layers have a slightly different cut and shape than men’s varieties, but our favorites remain the same regardless of gender. For a close look at our favorite base layer bottoms and why we chose them, take a look at our buyer’s guide. In the meantime, here’s a short list of our favorites.Best base layer bottoms for women:
- Smartwool Merino 150 Bottoms
- Patagonia Capilene Midweight Bottoms
- REI Co-op Lightweight Tights
- Icebreaker 260 Tech Base Layer Tights
- Carhartt Base Force Heavyweight Bottoms
Thermal underwear is separated into three categories based on it’s insulative and moisture-wicking properties: lightweight, midweight, and heavyweight. Which pair is right for you depends on both the weather and the way that you intend to use your pair.
Generally speaking, colder weather necessitates heavier layers; while high-output activities favor a lighter base for increased breathability. For our top picks of thermal underwear and more details on how to find the right pair for you, take a look at our buyer’s guide.
For cold conditions, you need the warmest, thickest pair of thermal underwear you can find. Beyond that is up to personal preference- between wool and synthetics there are many benefits and drawbacks. For more on thermal underwear and how to make an informed choice about your next heavy duty pair, take a look at our buyer’s guide.
For now, here’s a short list of our favorite heavy duty options:Best thermal underwear for cold weather:
- Carhartt Base Force Heavyweight Bottoms
- Icebreaker 260 Tech Base Layer Tights
- Patagonia Capilene Heavyweight Bottoms