The Best Thermal Underwear of 2024 for Men

It’s easy to let low temperatures and bad winter weather keep you locked indoors, but the right layering means you don’t have to freeze to stay outdoors through colder months. Like any good base layer, the best thermal underwear for men helps transport moisture away from the body and out of your layers. Getting soaked with sweat is a sure-fire way to be really cold, so make sure you wear just enough on top of your thermals to avoid overheating.

In addition to moisture transport, these base layers help keep some of your body’s heat close, so you don’t have to bundle up like that kid in A Christmas Story just to go outside. Keeping layers to a minimum makes you more mobile, whether you’re out for a run, chopping firewood, or just walking in a winter wonderland.

Men don thermal underwear for as many reasons as they have to go outside in winter, so we’ve shared our favorites in a range of categories to pinpoint your perfect set.

Best Overall Men’s Thermal Underwear: Artilect Boulder Crew Top and Leggings Artilect Boulder Crew Top and Leggings

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Both merino wool and synthetics have had their day as the base layer of choice. Recent innovations blending the two, such as Artilect’s Boulder 125 base layers, have managed to capture the best qualities of both. The bulk (85 percent) of the Nuyarn merino fabric is odor bacteria-suppressing wool, but the nylon gives it great stretch without feeling like spandex. The inside is also incredibly soft to the touch and flatlock seams aren’t noticed at all. The fit is athletic, making this base layer set an option for pretty much any winter activity and maximizing moisture transport. This 125-weight set is the lighter of two Artilect thermal sets. Their 185-weight is appropriate for the coldest temperatures and lower-intensity activities outside, but the 125s should be plenty for most people and are definitely the right choice for high-output sports such as running and backcountry ski touring.

• Materials: 85% merino wool, 15% nylon
• Colors: Black, Kalamata/Ash, Dusk Blue/Black
• Sizes: S–XXL

Related: The Best Camping Showers and Washing Gear for Keeping Clean on Adventures

Best Merino Wool Men’s Thermal Underwear: Ibex Woolies Zip Top and Bottoms Ibex Woolies Zip Top and Bottoms

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We love the feel of modern merino apparel against the skin, but our only gripe has been that the garments tend to stretch out over years of hard use and can wear faster than seemingly indestructible synthetics. This update to Ibex’s popular Woolies base layer uses a Nuyarn merino blend fabric similar to our top overall pick from Artilect. The difference here is a slightly more relaxed fit than Artilect’s athlete-minded tailored cut and more stylish color options. The result is a cozy yet functional set of thermals that you can wear day after day without worrying about synthetic stink or premature wear. Ibex makes a crew neck long-sleeve in addition to the ¼ zip top, but the extra-wide neck on the crew isn’t our favorite. We’d recommend the zip unless you like that muumuu neck cut for your base layer tops.

• Materials: 85% merino, 15% nylon
• Colors: Black Gray Stripe, Lake Effect, Olive Drab, Black
• Sizes: S–XXL

Best Value Men’s Thermal Underwear: Hot Chillys Pepper Top and Bottoms Hot Chillys Pepper Top and Bottoms

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In the ’80s, Hot Chillys was one of the first companies to popularize form-fitting, moisture-wicking thermals for active pursuits such as skiing. Their lineup has evolved with the times, and while they make plenty of higher-end pieces, the Pepper line delivers great value with a fully synthetic mid-weight layer that’s a great all-around set for any outdoor endeavor. The fit is relaxed so it might not meet the demands of high-intensity winter sports, but it’s a great all-around thermal for staying warm outside in a range of activities. The Pepper has a double-layer construction that helps retain warmth close to your body but efficiently transports moisture away from the body to keep you dry.

• Materials: 100% polyester
• Colors: Black
• Sizes: S–XXL

Best Men’s Thermal Underwear for Skiing: Obermeyer UltraGear Zip Top and Bottoms Obermeyer UltraGear Zip Top and Bottoms

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Keeping your core warm while skiing is the best way to help avoid cold hands and feet—the main reason people cut an epic ski day short. For warm, sunny spring skiing, almost any light thermals will do, but for dark January powder days on the chairlift, Obermeyer’s fleece mid-weight UltraGear layers are perfect for adding breathable warmth under weatherproof ski shells and pants. Some people fear the cold and rock insulated jackets and pants skiing, but we prefer Gore-Tex shell outerwear that lets us adjust our under layers to the weather. These UltraGear layers are usually enough on their own, but for the coldest days, they have a relaxed enough fit to be worn as fleece mid-layers with lighter, tight-fitting base layers underneath.

• Materials: 92% polyester, 8% elastane
• Colors: Black, Knightly
• Sizes: XS–XXL

Related: 5 Intense Workouts to Build Stronger Shoulders

Best Men’s Thermal Underwear for Biking: Pearl Izumi Quest Jersey and Bib Tights Pearl Izumi Quest Jersey and Bib Tights

Justin Park

Dressing for cold-weather biking can be tough. On the one hand, you’re usually generating a ton of body heat, which can easily lead to soggy layers within a few minutes on the road or trail. On the other, you’re often fighting cold hands and feet and riding fast and into wind, which can chill you quickly. When it’s cold and we’re pedaling, we like to pair heavy gloves and shoe covers with warm but highly breathable base layers and wind-blocking jacket and pants when necessary. The Pearl Izumi Thermal Bib Tights pair a mid-weight, highly stretchy fleece material on the legs with a thin, breathable upper and a built-in chamois pad, so you don’t have to squeeze a layer underneath. There are very few seams to irritate your skin and the legs fit snug, so you get maximum moisture transport when you’re grunting out a climb, with zero material flapping around that might catch in your gears. The Quest Thermal Jersey isn’t quite as form fitting, so it helps retain body heat and has a full-length zipper if you need to shed steam fast to avoid getting sweaty.

• Materials: 100% polyester
• Colors: Black
• Sizes: S–XXL

Best Men’s Thermal Underwear for Warmth: Hot Chillys La Montaña Zip Top and Bottoms Hot Chillys La Montaña Zip Top and Bottoms

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Sometimes winter conditions can be extreme and they call for extreme warmth, even in your base layers. Whether you’re trying to hold out all morning in a deer stand, watching a football game with your butt on aluminum bleachers, or just out for a walk in subzero temps, Hot Chillys La Montaña base layers are about as warm as thermals get before they become something else. While they can be worn as an..