Whether you’re into snow sports or simply want to prepare for winter weather, base layers can help insulate heat while wicking sweat away from your skin.
asserted
layers → ’re → skin
Those base layers can include thermal underwear, also known as long johns, as well as other types of apparel like shirts and accessories.
asserted
layers → include → shirts
Below you’ll find everything you need to know about base layers, including tips on how to shop for them, from Ashleigh McClary, a hiking enthusiast and Backcountry "Gearhead" (outdoor expert and customer service specialist), and Ben Clower, an outdoor enthusiast and marketing coordinator at JAX Outdoor Gear in Colorado.
asserted
you → find → Colorado
The best thermal underwear in 2026
The list below includes expert recommendations and some personal favorites of NBC Selected staff.
asserted
list → include → staff
Editor’s pick
Former NBC Selected commerce editor Jordan Bowman loves these affordable Uniqlo tights for their flexible stretch and wide size range.
asserted
Bowman → love → range
In fact, he says he can’t survive a winter without them.
asserted
he → say → them
“These are a necessity when temperatures drop in New York City,” he says.
asserted
he → drop → City
“If I see a gust of wind, that’s when I start reaching for the Heattech tights.”
asserted
I → see → tights
The tights are sleek and fitted for easy layering, and anti-odor, according to the brand.
uncertain
tights → fit → brand
They’re designed to last through everyday wear and tear and hold their shape over time, according to the brand.
uncertain
They → design → brand
Best men’s pants
These 100% Merino wool bottoms from Smartwool come recommended by Clower.
asserted
bottoms → recommend → Clower
They have a slim fit that hugs the body and a mid-rise waistband designed to sit just at or below the belly button, according to the brand.
uncertain
that → have → brand
To help reduce sagging, they also have a curved back seam for added support.
asserted
they → help → support
To wash, the brand recommends a warm water, gentle cycle and drying on a low tumble.
asserted
brand → wash → tumble
These bottoms are available in both men and women’s versions along with plus-size options up to 4X.
Best men’s shirt
Another recommendation from Clower, this crewneck thermal shirt is the matching top to the Smartwool bottoms on this list.
asserted
shirt → match → list
Like the bottoms, this top has a slim fit and is made from the naturally odor-reducing Merino wool, according to the brand.
uncertain
top → have → brand
The top has a flatlock seam, which is used in outdoor gear to reduce chafing, and shoulder panels instead of seams for a smoother look.
asserted
which → have → look
For people with sensitive skin who find Merino wool too itchy, McClary suggests Patagonia’s “incredibly soft and comfortable” Capilene Thermal base layers as an alternative.
uncertain
McClary → find → alternative
The fabric is Polartec Power Grid fleece, a mid- to lightweight base layer material designed to keep you warm without overheating your body, according to the brand.
uncertain
fabric → design → brand
This hoodie has a regular fit, meaning it’s slightly looser than a fitted top, and can be layered with other pieces.
asserted
it → have → pieces
They’re flexible and breathable, making them great for high-intensity activities like snowboarding, skiing, hiking and more.
asserted
them → ’re → snowboarding
They have a reinforced crotch area to better allow for unrestricted movement, and flat seams to prevent chafing, according to the brand.
uncertain
They → have → brand
This Merino wool half-zip top from Icebreaker is great for layering during extra-cold days, or for more active winter hobbies.
asserted
top → layer → hobbies
It’s soft and lightweight, with design features like a reinforced underarm to allow for greater mobility, and offset shoulder seams to help minimize friction, according to the brand.
uncertain
It → ’ → brand
The top has a slim, body-hugging fit for easy layering.
asserted
top → have → layering
These base layer leggings are a favorite of former NBC Selected associate reporter Bianca Alvarez, who wears them for winter activities like snow tubing and skiing.
asserted
who → wear → tubing
“I love that they keep me warm but not to the point of overheating,” she says.
asserted
she → love → overheating
She also likes the mesh calf design, which she says “makes the super soft material very breathable”, and how the long cuffs are comfortable to wear, even with snow boots.
asserted
cuffs → like → boots
Alvarez says that since her mom first bought these tops on a Costco run, her entire family wears them regularly as base layers under their winter clothes.
asserted
family → say → clothes
Initially, she thought they were too thin to be effective, but says that after trying the top, she was happily wrong.
asserted
she → think → top
“These are one of the warmest thermal layers I own,” she says.
asserted
she → own → layers
“I wear it on its own, under vests and of course, under winter jackets.”
asserted
I → wear → jackets
She also likes that the top is available in packs of two, and is machine washable.
asserted
top → like → two
“It feels softer and softer after every wash,” she says.
asserted
she → feel → wash
These long underwear are soft and stretchy to allow for less restrictive movement, according to the brand.
uncertain
underwear → allow → brand
They’re made from a poly-spandex blend that gives them a flexible feel, and are also designed with a sweat-wicking Thermaskin technology to keep your skin dry while wearing.
asserted
that → make → skin
The full elastic waistband keeps the thermal underwear in place, while the fabric has odor-controlling properties to keep you fresh at all times.
asserted
fabric → keep → times
This thermal underwear set is designed to be an everyday base layer, according to the brand.
uncertain
set → design → brand
Each piece is lined with fleece for extra softness, and the set is highly rated by reviewers on Amazon.
asserted
set → line → Amazon
The top is available in scoop neck, crew neck and V-neck styles, and both pieces can also be worn without a top layer.
asserted
pieces → wear → layer
…and 30 more, not listed.
The Aporia
