It can be a bit hit and miss trying to choose the best base layer for men. Have a read through our base layer guide and check out our range of recommendations.
Whether you’re out for a winter stroll or hiking to cold temperatures at high altitudes, there’s a great selection of men’s base layers to choose from.
In this article we list our the best base layers for men in 2020. After that, if you’re totally new to buying base layers, we walk you through some of the key things you need to consider when buying a men’s base layer to meets your needs.
If you just don’t have time for that and just want to know what our top choice is, we recommend the SmartWool Men’s NTS Mid 250 Crew, it’s our number one choice for the best men’s base layer.
Best Base Layers for Men
We’ve selected five of the best base layers, of varying thicknesses and fabrics, so whatever your preferences, time of year and activity level, you’ll will find one that’s made to suit your needs. Here’s our best base layers for men.
#1 Smartwool Merino 250 Base Layer Crew
- 100% natural Merino wool
- Shoulder panels for increased comfort carrying a backpack – no shoulder seams
- Excellent temperature regulation
- Does not hold odors
- Interlock knit with flatlock seams for comfort and ease of movement
- Weighs a lot when wet
This slim-fitting, 100% merino wool crew from Smartwool is our favorite base layer for when temperatures drop.
The excellent thermoregulatory quality of merino wool means you will stay warm in the cold, but you won’t heat up too much during periods of exertion.
Thanks to the wool’s superior wicking and fast-drying nature, any perspiration is moved away from your skin, keeping you dry and warm. As with all Merino wool garments, this base layer does not hold on to odors thanks to the wool’s natural antibacterial properties.
So, whether you’re wearing it for hard summit hikes or for days on end during extended backcountry trips, you won’t need to worry about washing it out or putting up with the stench of dried sweat.
This also helps to prolong the garments longevity as you really can wear it for longer between washes.
This base layer is second warmest on our list. As it’s warm enough to wear alone as well as a base layer, this makes it one of our most versatile pieces and its good looks mean you can also wear it out and about.
As a thicker base layer, it is naturally less breathable than thinner ones, however, thanks to its thermoregulatory qualities and excellent wicking properties, it keeps moisture well away, putting it almost on a par with more breathable models.
However, unlike more breathable models, this crew provides you with added warmth and wind protection so when you pause for a break, you won’t instantly feel cold.
Comfortable and non-itchy, this base layer is slim fitting without being too tight. The interlocking knit and flatlock seams add comfort and ease of movement.
Unlike some other base layers, this one is long enough to keep you fully covered when moving about, even with overhead stretches. The shoulder panels replace shoulder seams for extra comfort when carrying your backpack.
The main downside is the price, however, look after it well and it will last. It also becomes heavy when wet, like all wool, although thanks to its odor-resistant nature, you’re highly unlikely to need to wash it on the trail.
#2 Rab Merino+ 120 LS
- Excellent breathability with Rab’s 37.5 technology
- Comfortable and lightweight
- Second skin fit with unresisted mobility
- Tapered sleeves and full-length gusseted underarms
- Warmth for mild winter conditions or colder with intense activity
- Thin merino and polyester fabric is not very durable
The Rab Merino+ 120 LS is a popular lightweight base layer created using a combination of merino and polyester fibers for outstanding results.
This combination makes for a warm base layer that is suitable for mild or cold conditions with more intense activity, thanks to its superior levels of breathability.
Rab’s outstanding 37.5 technology enhances moisture capture and evaporation on a molecular level to keep you warm and dry. If you enjoy keeping active year-round and more challenging hikes, then this could be the best base layer for you.
Highly breathable and extremely fast drying, the Rab Merino+ also has the warmth, thermoregulatory and odor-resistant qualities of a pure merino wool top, giving you the very best of both worlds.
Its stretchy, lightweight material fits like a second skin for unhindered ease of movement, essential for increased comfort levels, especially on more technical hikes.
The full garment-length gusseted underarms allow this base layer to move with you and its long torso won’t leave you exposed when stretching or bending, while its tapered sleeves make it ideal for layering with ease.
The shoulder panels mean you won’t have shoulder seams digging into your skin under the weight of a fully loaded backpack.
If you tend feel the cold and don’t often work up a sweat when you’re out, then the Rab Merino+ 120 is probably not the right base layer for you. It is also not as durable as some of our other recommendations, although with good care it should still last for quite some time.
If you need a comfortable, highly breathable base layer that fits like a glove, then this really is the one to go for.
#3 Under Armour Coldgear Reactor
- Four-way stretch construction for greater ease of movement
- Mesh side panels for enhanced breathability
- Lightweight, quick drying and breathable polyester and elastane fabric
- Soft brushed side next to skin for breathable warmth
- Anti-odor treatment prevents odor buildup
- Neck can be tight to get on
- Not as warm as merino wool
The Coldgear Reactor base layer by Under Armour is a good choice for staying active in colder weather.
This polyester and elastane blend won’t provide you with the same level of warmth as a merino or merino blend base layer, however, if you’re looking for a durable, synthetic base layer for moderate to intense activity, then the Coldgear Reactor would make a good choice.
Highly breathable, this base layer wicks sweat and dries extremely quickly. For those of you who don’t want to have wool next to your skin, the soft brushed interior provides extra insulation and a warming sensation against bare skin.
Breathability is further enhanced by the side mesh panels, so if you easily build up a sweat, this could be a good base layer to consider.
While there is an anti-odor treatment to prevent the growth of odor-causing microbes, unlike merino wool, you won’t want to be wearing this for more than a day before washing.
With its four-way stretch fabric and articulated cuff, the Coldgear Reactor fits well and moves with you, although it’s close fitting neck can be a little difficult to get on for some.
The side mesh panels also allow for greater freedom of movement, while the shoulder panels make for comfortable wearing with a backpack.
While this base layer lacks some of the warmth of a merino top, it is a good choice if you are looking for extra breathability with a good amount of stretch and a snug fit.
#4 WoolX Glacier Heavyweight Base Layer
- Heavy interlock knitted merino layer
- Designed for extreme cold – 18.5 micron, 400g/m
- Underarm gusset
- Cuffs with thumbholes
- Stays tucked with slight back drop
- Heavy when wet
- Less breathable
If you are looking for a base layer for extreme cold or for wearing when camping, then the WoolX Glacier is the warmest base layer in our selection. Its dense, interlock knitted construction is extremely warm and will protect from the wind as well as the cold.
In spite of its density, it is also fairly breathable thanks to its 100% merino wool construction, although it is better suited to lower intensity activities where you will really benefit from its extra heat.
If you’re considering a cold winter backpacking trip, then this base layer would be an ideal choice to keep you warm even when you’ve set up camp for the night, as well as during breaks on the trail. Its wool construction also stops odors from building up, even after several days’ wear.
Although denser garments are naturally less breathable, thanks to its merino wool construction, the WoolX Glacier still breathes surprisingly well and does a great job of wicking sweat away from your body.
While you probably won’t need such a heavy layer for high intensity activities, this base layer is fairly adaptive thanks to merino wool’s thermoregulatory qualities.
Going from a steep ascent with your fully loaded backpack to a well-deserved break at a windy summit won’t leave you over heating then suddenly shivering with cold.
The Glacier is a snug fitting, comfortably soft base layer that has been designed with outdoor pursuits clearly in mind. It stays tucked thanks to its slight back drop and sufficient torso length.
The cuffs feature thumbholes, making layering easier and providing extra warmth and protection for your hands, while the underarm gussets offer complete freedom of movement, ideal when you’re maneuvering a heavy backpack.
There are shoulder seams, however, they don’t cause any discomfort. The only real downsides are less breathability due to the thickness of this heavyweight base layer and the fact that it is very heavy when wet.
All in all, a fantastically warm base layer ideal for extremely cold hiking and backpacking trips. You could also use it over a lighter, daytime base layer when temperatures drop overnight and around camp.
#5 Helly Hansen Lifa Thermal Base Layer
- Made from polypropylene that quickly moves moisture away from your skin
- Ideal for high intensity activities in cold weather
- Non-itch, allergy neutral fabric with flatlock stitching
- Lightweight and quick drying
- Limited lifetime warranty
- Not very warm when you stop exercising
- Short body
If you’re looking for an inexpensive base layer for intense hikes, where you’ll be creating a lot of body heat, then the Helly Hansen Lifa Thermal Base Layer could be the one for you.
It is lightweight and dries extremely quickly, wicking sweat away from your skin immediately thanks to its polypropylene construction.
If you often tend to feel hot rather than cold and prefer trail running or fast-paced, energetic hikes, then this base layer would be a natural choice for all seasons thanks to its excellent breathability.
Although the Lifa is quick drying and breathable, it is not very warm once you stop moving. It could make a decent base layer for milder seasons, however, if you are not expecting to be really active on the trails, your needs would probably be better served by another type of base layer.
Furthermore, the athletic cut of this garment makes it a little on the short side. The low-bulk cuffs and flat-lock stitching make the Lifa easy to layer, while the polypropylene fabric is comfortable against your skin.
On the whole, the Lifa base layer is an inexpensive option that will not keep you very warm in cold winter weather, but it will dry quickly, wick away sweat and breathe.
So, if your activity levels and climate fit in with these main qualities, then the Helly Hansen Lifa could be made for you. It is also covered by Helly Hansen’s limited lifetime warranty.
What are Base Layers?
Base layers are close-fitting undergarments that are worn next to the skin. They provide an extra layer of insulation helping you to stay warm. They also have an important role to play in keeping you dry, especially during more intense activities.
The layering approach to outdoor wear allows for a combination of different garments that can be altered for varying circumstances such as weather, terrain and exercise intensity, while catering to individual needs and preferences.
Base Layer Features
When you’re looking for a new base layer there are some important features to bear in mind. Above all you want to stay warm and dry, but ease of movement, comfort and resistance to odors are some of the other base layer features you may want to consider.
It’s important to select a base layer made from a fabric that is suited to your needs. Here are some of the most popular base layer fabrics and their main qualities:
- Merino wool – Super soft, comfortable and natural, Merino wool is highly reputed for its excellent thermoregulatory qualities, keeping you at an ideal temperature despite temperature fluctuations or an increase or decrease in activity levels. It is also naturally odor resistant and will not build up a stink like some synthetic garments do.
- Synthetic/wool blend – This offers the best of both worlds, the warmth of wool and its thermoregulatory qualities with the breathability of synthetic fabrics. Wool/synthetic blends tend to add greater durability to woolen garments and make them more suitable for higher activity levels.
- Polyester/synthetic blend – Polyester or other synthetic base layers tend to perform poorly at keeping you warm in cold conditions. They do, however, provide excellent breathability and are fast drying. If you tend to not feel the cold too much and are planning on high intensity activities, then a synthetic base layer will provide extra insulation with superior breathability.
Base layers are available in either lightweight, mediumweight or heavyweight. The heavier the weight, the thicker and denser the garment will be, keeping you warmer.
Colder temperatures and lower activity levels are better suited to heavyweight base layers, while milder temperatures and more intense activities are better suited to lightweight base layers, that tend to breathe better but keep you less insulated.
Base layers should fit snugly. To effectively wick moisture away, they need to be touching your skin. You’ll also find them more comfortable and easier to layer when they are close fitting.
However, you do not want them to be as close a fit as compression garments. Base layers insulate by trapping a small amount of warm air close to your body. So, they’ll need to fit closely but not too tightly.
You may prefer to purchase a base layer that is slightly longer than your regular t-shirts, this will enable you to keep yourself fully covered when stretching out and your layer of warm, insulating air will not be lost if you can keep your base layer tucked into your pants.
Long, snug and relaxed is the ideal fit for an effective base layer. For some brands you may prefer to size down if you’re often between two sizes.
It goes without saying that base layers need to be comfortable as they sit next to your skin. While Merino wool is naturally soft and comfortable next to your body, synthetic fabrics may have a brushed interior face to improve heat insulation and add a cozy sensation.
The actual knit of the garment itself will improve comfort levels, as will any stretchiness, allowing for greater ease of movement. Shoulder panels, flat-locked seams, printed tags, there are numerous features which can improve your comfort levels.
Comfort is also dependent upon the article’s thermoregulatory properties, its ability to wick away sweat and its breathability. Keeping you warm and dry is by far the most important comfort that a base layer can achieve.
It’s important to stay dry in order to keep warm and comfortable. Even low-intensity activities can cause you to perspire and if your base layer lacks breathability, you could find yourself uncomfortably damp which could lead to extreme cold or even hypothermia.
You’ll need your base layer to wick sweat away from your body to keep you warm, dry and comfortable. This requires fabrics that dry quickly, enabling efficient moisture transfer and evaporation.
Merino wool is naturally odor-resistant and can be worn several times without washing. Even after several uses, it probably still won’t smell.
Synthetic fabrics, on the other hand, will need washing after use to prevent bad odors building up. Some synthetic fabrics are treated to prevent this odor build up. This should mean that they smell less, however, in reality they often can smell pretty bad, nonetheless.
Base layers are mostly minimalist for easy layering, however, you may want to look out for underarm gussets and any panels that may help improve ease of movement.
Thumbholes can also be a nice addition and provide a little extra warmth for your hands, while stopping your sleeves from riding up. You should also pay attention to seam location, especially on the shoulders.
Neck styles vary from model to model and really come down to personal preference, while extras such as mesh panels for added breathability may be of interest if you also enjoy high-intensity winter activities.
Choosing the Right Base Layer
When choosing your base layer, you need to select one that is right for you and your needs, taking into account your personal preferences, your activity levels, the temperature and location.
Challenging, intense activities will require breathable, lighter weight base layers or else you’ll risk overheating, while if you tend to feel the cold and are planning a winter leisurely hike with plenty of stops to admire the snowy scenery, then you’d be better off with a less breathable but warmer, heavier weight layer.
A medium weight Merino wool base layer or a mixed wool and synthetic layer is a great versatile all-rounder for hiking, where you may have a combination of more intense activity for ascents, pauses and slower sections.
A medium weight will ensure you stay warm when you stop, without overheating on the more challenging sections of trail.
Finding the best base layer for men is all about knowing what you need and prioritizing those needs, while taking personal preferences into account and dressing for the occasion with a good selection of complementary layers.
For some people a mid-weight merino base layer fulfils all of their needs, others prefer to have a heavier weight for the depths of winter and a synthetic blend for other seasons or faster-paced adventures.
Ultimately, whatever works best for you and keeps you warm, dry and comfortable is the best base layer there is!