The Most Comfortable Long Underwear for Men 2025

Tops and bottoms to help you stay warm and stylish this winter season.

Thermal underwear, long underwear, long johns, or base layers, whatever you prefer to call them, they’re a great way to stay warm when the temperatures drop.

For the uninitiated, long underwear is the form-fitting base layer worn under your everyday clothes that provides an extra layer of warmth.

A high-quality pair of long underwear will not only be very comfortable to wear but also do a much better job of retaining body heat than your regular clothes could do on their own.

Additionally, most have breathable designs to keep you from overheating and moisture-wicking fabric to keep you dry.

So, whether you’re lounging around the house or forging out into the cold, nothing beats long underwear in the winter months when it comes to warmth, comfort, and style.

We’ve put together a list of the best long underwear sets to keep you toasty and comfortable this winter season.

Check it out, grab a few sets, and enjoy those chilly months both outdoors and in.

How We Make Our Picks for Most Comfortable Long Underwear

Look, we get it. Determining what makes a great pair of long underwear can be a pretty subjective thing.

So, how do we decide which make our list for the most comfortable? 

We tested a wide range of long underwear brands and put them through the rigors of daily life and active situations.

And, as a result, we can say for certain that 3 specific qualities make for an objectively more comfortable experience.

Reviewing long underwear from leading men's brands.

1. Premium fabric blends that support active bodies.

You move your body in a wide range of motion throughout the day and it doesn’t take much for it to experience distracting irritation.

We prioritized options with naturally soft fabric that add a touch of stretch (i.e. spandex, elastane, etc.).

We’ve also found that while you may end up paying a little more for premium fabric, it tends to stay in better shape for longer.

2. Breathable warmth to regulate body temperature.

Of course, with long underwear you’re looking to add a layer of warmth to your outfit.

But it’s a tricky balancing act because you also don’t want to find yourself overheating, wearing around a puddle of your own sweat.

We opted for long underwear brands that integrated breathability into their designs to strike this crucial balance.

3. Ergonomic features that prioritize the male anatomy.

It’s crazy how many men’s long underwear options don’t seem to properly consider the male anatomy in their design.

After all, you’re not a retail display mannequin yet some brands seem to design their underwear that way.

Underwear that pays attention to the human body and how it moves tends to layer better under clothing, cut down on adjustments and bunching, and help you forget it’s even there.

Note: Featured products are independently selected and reviewed by The Underwear Review. If you purchase through our links, we may earn commission.

1. Tommy John SleekHeat Long Johns

The Tommy John SleekHeat Long Johns feature a silky soft premium fabric that’s featherlight and non-pilling.

These long johns have a streamlined fit that perfectly hugs your body while providing a non-restrictive full range of motion.

Shop at Tommy John: Tommy John SleekHeat Long John Top

Shop at Tommy John: Tommy John SleekHeat Long John Bottom

Tommy John’s SleekHeat Long Johns feature signature smart fabric that keeps you warm outdoors and prevents overheating while indoors.

These long johns also utilize smart stretch technology to prevent moisture build-up.

Our Favorite Feature: The best layering option we've come across for everyday wear thanks to a streamlined fit, soft premium fabric, and plenty of stretch for a full range of motion.

2. David Archy Fleece Lined Thermal Set

The David Archy Fleece Lined Thermal Set features an incredibly soft fleece fabric in a slim fit that lays smoothly against your skin.

These thermals are double-sided for superior body heat retention and comfort.

Shop at David Archy: David Archy Fleece Lined Thermal Set

David Archy’s Fleece Lined Thermal Set features double-layer knee and elbow panels for improved durability and warmth.

The bottoms have a functional fly for convenient access and the top has a classic round crew neckline.

Our Favorite Feature: Luxurious double-sided soft fleece fabric for toasty warmth and a dreamy fit.

3. Smartwool Thermal Merino Base Layers

The Smartwool Thermal Merino Base Layers feature 100% Merino wool fabric in a slim functional fit.

These base layers utilize an interlock knit for enhanced comfort, breathability, and thermoregulation.

Shop at Smartwool: Smart Wool Thermal Merino Base Layer Crew

Shop at Smartwool: Smart Wool Thermal Merino Base Layer Bottoms

Smartwool’s Thermal Merino Base Layers feature a heavier weight fabric for warmth while minimizing chafing with flatlock seam construction.

The bottoms have a merino-covered waistband, and the crew uses a panel design to eliminate shoulder seams.

Our Favorite Feature: Very high-quality design and attention to detail with a warm, comfortable, and breathable fit.

4. Mack Weldon Tech Merino Jersey Long Johns

The Mack Weldon Tech Merino Jersey Long Johns feature a luxuriously soft modal fabric that’s ultra-lightweight and provides optimal stretch.

Shop at Mack Weldon: Mack Weldon Tech Merino Jersey Long Sleeve Crew

Shop at Mack Weldon: Mack Weldon Tech Merino Jersey Long Johns

Mack Weldon’s Tech Merino Jersey Long Johns utilize the technical performance properties of merino wool that’s naturally moisture-wicking and antimicrobial.

Our Favorite Feature: These have a soft and lightweight feel with plenty of stretch.

5. NATIVE TO WEAR Base Layer Set

The NATIVE TO WEAR Base Layer Set feature an incredibly soft merino wool that contains pure silver to evenly spread body heat for ideal temperature regulation in both cold and hot weather conditions.

Shop at NATIVE TO WEAR: NATIVE TO WEAR Base Layer Crew

Shop at NATIVE TO WEAR: NATIVE TO WEAR Base Layer Bottoms

NATIVE TO WEAR’s Base Layer Set incorporate Lycra stretch into the fabric for a stretchy second skin fit that provides maximum comfort and freedom of movement.

These base layer bottoms are breathable, sweat-wicking, antibacterial, and available in several colors.

Our Favorite Feature: Soft merino wool feel paired with impressive temperature regulation design.

6. Columbia Omni-Heat Infinity Baselayers

The Columbia Omni-Heat Infinity Baselayers feature a signature Omni-Heat thermal-reflective lining for advanced body heat retention without fabric bulk.

These baselayers utilize comfort stretch fabric for a snug fit that’s non-restrictive.

Shop at Columbia: Columbia Omni-Heat Infinity Baselayer Crew

Shop at Columbia: Columbia Omni-Heat Infinity Baselayer Tights

Columbia’s Omni-Heat Infinity Baselayers feature signature sweat-wicking Omni-Wick technology that moves sweat away from your skin and neutralizes odor for a long-lasting dry and fresh feel.

Our Favorite Feature: Omni-Heat technology provides heat without the bulk, making these a great layering option.

7. Thermajohn Thermal Long John Set

The Thermajohn Thermal Long Johns feature an extra soft fleece lining for extended comfort and heat retention.

These thermal long johns utilize 4-way stretch fabric for a no-chafe fit that’s also breathable and moisture-wicking.

Available on Amazon: Thermajohn Thermal Long John Set

Thermajohn’s Thermal Long Johns work great for layering up to fight cold weather or to wear on their own as a comfortable pajama option.

Our Favorite Feature: The soft fleece lining will keep you warm and comfortable without overheating.

8. Mr. Davis Long John Underwear

The Mr. Davis Long John Underwear features a buttery soft bamboo viscose fabric with added stretch for the perfect long underwear fit and feel.

This long underwear sports an anatomical shelf pouch that gently lift and supports and strategic ventilation to keep you from over-heating. 

Available on Amazon: Mr. Davis Long John Underwear

Mr. Davis’ Long John Underwear utilize a premium elastic waistband that’s durable and won’t bind or unravel.

Our Favorite Feature: A versatile and extra comfortable option with cooling airflow that’s perfect for layering, working out, or lounging.

Long underwear should fit snug to your body without restricting mobility.

If you’re looking for additional warmth in the colder winter months, long underwear is the most popular go-to option.

A full set of long underwear consists of both a top and bottom, though either can be worn separately on their own to match personal preference.

Additionally, tops and bottoms can often be purchased separately.

Both pieces are designed to be worn as base layers, which means they’re the first layers you put on and worn right against your skin.

Long underwear pieces are then typically layered with top/outer layers.

Testing long underwear options from leading menswear brands.

For this reason, your long underwear should have a snug, body-contouring fit.

This not only allows for additional layers to wear nicely over the top but it’s also what helps with body heat retention, keeping you warmer for longer.

When sizing your long underwear, look for a snug and comfortable fit.

It should fit close to your body but should not restrictive your movement or cause any discomfort.

Long underwear is typically worn out of sight, so you may want to keep this in mind when determining the length of your sleeves or legs.

However, this isn’t always a priority, especially when wearing long underwear for outdoor activities.

Additionally, the leg cuffs of long underwear are typically tucked into your socks.

This allows for a more polished appearance when wearing them indoors and helps to keep out the cold and snow when outdoors.

And if you’re all about comfort when it comes to your shirts, socks, and underwear be sure to check out the rest of our Most Comfortable Series.