Base Layer: 10 Best Thermal Underwear For Men

Long Johns, otherwise known as thermal underwear, otherwise known as man’s saving grace during the cold dark days of winter, have an interesting history. Initially unpopular upon their first introduction into England in the 17th century, it took almost 100 years for thermal underwear to become a popular sleepwear item, which is odd considering the climate in that part of the world. Whatever the case, it’s rumored the term “long johns” originated from the famed 19th-century boxer John L. Sullivan, where he can be seen wearing his thermal underwear juxtaposed against his iconic “put ‘em up” posture. Whether or not this is actually true remains to be verified, but hey, a good backstory never hurt.

Regardless of thermal underwear’s brawny history, the fact remains that this garment continues to serve us well on those cold nights, chilly mornings, and winter day hikes. They function as a lightweight, yet warm base layer, keeping everything as toasty as possible without making things uncomfortable. So it only makes sense that we highlight several of our favorite pairs that surely haven’t let us down over the years, providing ample comfort season after season. They’re our picks for the best thermal underwear around for men. Stay warm out there, and be patient, Spring is coming.

Polartec Power Dry

Polartec Power Dry

Staying warm at the campsite or while in transit in the wilderness during the winter can spell the difference between a relaxing weekend away or bone shaking misery. Don’t fall victim of the latter. LL Bean’s thermals are made from Polartec Power Dry fabric that are double plaited to wick away moisture and keep you warm in the process. They are fast drying, designed for stretch and mobility, are machine washable, and are built to offer a smooth and comfortable fit.

Purchase: $40

REI Co-op Midweight Base Layer

REI Co-op Midweight Base Layer

Made right here in the USA, these base layer thermals from REI are outfitted to keep you toasty in your wintertime outdoor pursuits such as skiing, snowboarding or hiking because cold weather is no excuse to remain indoors all season. They’re made from a durable polyester and spandex blend that works to wick moisture away, a mineral-based LAVA finish to help keep the pair odor free, and a flat-seam construction along with a crotch gusset to keep your as comfortable as can be while on the go and in-action in the outdoors.

Purchase: $50

Icebreaker Bodyfit

Icebreaker Bodyfit

Made from Merino Bodyfit, this pair of Icebreakers are purposed to help you enjoy the empty winter running trails and campgrounds this season. The fabric is lightweight and won’t bunch up, the flatlock stitching prevents chaffing, and their slim fit offers maximum comfort and minimal resistance in just about any outdoor activity. Wear them around the house as well if needed. They’re that comfortable.

Purchase: $54

Mammut Klamath

Mammut Klamath

Great for any activity from mountaineering to Netflix and chilling, these Mammut thermals are made with a Polartec Power Wool, boasting an incredibly soft outer layer to keep you comfortable no matter what. Their quick drying nature also lends itself to odor resistance and a highly breathable character. A comfortable waistband keeps these things fitting fantastically, an athletic fit maintains maximum comfort, and a soft feel ensures the Mammut Klamath thermals will be your top choice when the mercury decides to take a dive.

Purchase: $55

Minus33 Midnight Bottom

Minus33 Midweight Bottom

Obviously, there’s nothing quite like a pair of 100 percent Merino wool thermals. And this pair from Minus33 will keep you warm throughout even the coldest of nights. They function as a midweight base layer, featuring flat lock seams that work to prevent chafing, and are machine washable so there’s no need to worry about ruining this pair of comfortable thermals during a routine cleaning.

Purchase: $66

Tasc Men’s base Layer

Tasc Men’s Base Layer

Tasc Performance is quite the innovative brand, executing in ways that go beyond the norm. This pair of base layer thermals is one such example, combining Merino Wool with their Bamboo Performance technology to develop a fabric that’s both extraordinarily comfortable and athletic to help you maintain warmth during those cold winter evenings. They also absorb and release sweat in a quick manner, regulate body temperature, and are machine washable to boot.

Purchase: $70

Under Armour UA Base

Under Armour UA Base

Built of bitter cold, Under Armour’s Base thermals won’t weight you down in their effort to keep you warm and dry. They feature a negative grid interior that helps to trap hot air and a four-way stretch composition that helps you maintain mobility no matter what cold weather activity you might be undertaking. Anti-odor technology also keeps you smelling fresh, and UA’s Moisture Transport System will wick away sweat with ease.

Purchase: $75

Patagonia Capilene Thermal

Patagonia Capilene Thermal

Everyone’s favorite outdoor brand knows a thing or two about keeping warm in the wintertime. Case in point, these Capilene thermals feature a Polartec Power Grid fabric (polyester/spandex blend) that’s both smooth and soft for amplified comfort. They also feature a gusseted crotch for uninterrupted mobility, flat-lock seams to minimize chafing, and outfitted to keep you warm and dry wherever that snow-covered tundra may lead you in these final weeks of winter.

Purchase: $89

Arc’Teryx Satoro AR

Arc’Teryx Satoro AR

Designed with backcountry touring in mind, the Satoro thermals utilize Nucliex STR 180 wool for a next-to-skin fit and maximum warmth. It’s a lighter weight wool, offering enhanced mobility and comfort for those long hikes through the wilderness, and the nylon core of the fabric allows these thermals to be 20 percent stronger and 50 percent more abrasion resistant than other offerings in the market. If high performance is what you demand, then this pair will surely satisfy.

Purchase: $109

The North Face Summit L1

The North Face Summit L1

There’s no doubt in the integrity and execution of North Face products, especially when it comes to layers. This pair of base layer North Face Summit L1’s are built for harsh climbing environments. But whether or not you plan of ascending Everest anytime soon, this pair of thermals will provide ample warmth and comfort be it on the slopes or lounging around the cabin. They’re made from a warm Thermolite fabric, boast a specialized knit to keep key areas warm, minimal seams for additional comfort, and are engineered to trap body heat.

Purchase: $125