The 12 Best Pairs of Thermal Underwear for Men and Women, According to Thousands of Customer Reviews

Rebecca Carhart
·11 min read
long underwear men and women
long underwear men and women

Courtesy of respective brands

Every year when the temperature starts to dip, you likely add a durable winter coat and a slew of cozy sweaters and bottoms to your rotation. But if you find that you are still cold despite wearing these heavy-duty layers, it might be time to invest in a set of thermal underwear, too.

Thermal underwear act as a base layer to not only provide extra warmth, but also wick moisture away from the body, which can help keep you dry and prevent you from catching a chill. While most people wear thermal underwear for outdoor winter activities like hiking, skiing, and snowshoeing, many find them so warm and comfortable that they wear them to lounge around the house as well.

Related: The 14 Best Winter Hiking Boots for Men and Women, According to Thousands of Customer Reviews

When shopping for thermal underwear, you'll want to find a pair that fits snugly to trap in body heat but is still lightweight and flexible enough that you can move around with ease. Some options pack on additional features, like odor-resistant fabric to keep you smelling fresh or flatlock seam construction to prevent chafing.

There are plenty of styles and materials to choose from, including luxe wool, silk, and more affordable (and easier to care for) cotton blend options. So to help you find the best pair of thermal underwear for your needs, we scoured thousands of customer reviews to see which options people say kept them warm and toasty in frigid temperatures.

These are the best pairs of thermal underwear for women:

These are the best pairs of thermal underwear for men:

Whether you're looking for a cozy wool men's option or a lightweight silk women's base layer, these are the 12 thermal underwear sets that shoppers love the most.

Best Women's Thermal Underwear

Best Overall: Thermajane Thermal Underwear Set

This thermal underwear set by Thermajane is a number one best-seller on Amazon for a reason. Made from a super soft four-way stretch material, this moisture-wicking base layer is both lightweight and flexible. Shoppers love that it fits snuggly and the fact that it's fleece-lined for extra warmth. The size-inclusive set ranges in size from XXS to 3XL, and there are 11 different colors to choose from. "These are amazing," raved one customer. "Thin and comfy, but so nicely made and very, very warm. Perfect to wear as pajamas or under clothes to keep you warm. They feel like a second skin without binding anywhere. They'd be perfect under ski clothes! The outside is a smooth, lycra type fabric so it's easy to slide other pants on top, and the inside is super soft, warm fleece."

To buy: from $22, amazon.com

Best Affordable Option: Amazon Essentials Thermal Long Underwear Set

This thermal underwear set from Amazon Essentials is another popular choice thanks to its comfort level and affordable price point. The top and bottoms are made from a cotton/polyester blend that customers say is super soft and cozy against their skin. The elastic ribbed cuffs on the wrist and ankle hems keep the pieces from bunching up when other clothes are worn over them, and they're machine-washable for added convenience. One reviewer called them a "great base layer for outdoor work" before adding, "I needed layers for an all-day, outdoor hedge laying workshop in 32 degrees Fahrenheit weather and on uneven terrain. This set proved warm enough without being suffocating, and snug enough at ankles and wrists to keep the cold out without inhibiting movement or circulation."

To buy: from $20, amazon.com

Best Wool Option: Smartwool Merino 250 Wool Base Layer Top & Bottom

If you're looking for a thicker wool base layer to wear in freezing temperatures this season, check out these Smartwool options. Each piece is made from 100 percent Merino wool that is not only breathable and odor-resistant but also has thermoregulation capabilities to keep you warm as you ski, snowshoe, or hike outdoors. The wool base layers are more expensive than other options on this list, but shoppers say they are well worth the price. "This baselayer is my go-to piece when I am heading to the mountains for a skiing adventure," wrote one reviewer. "It is comfortable, warm and incredibly durable (I fall a lot, I'm not a pro hahaha). This piece stands up to an entire day on the mountain, without getting soaked in sweat and maintains its breathability. I highly recommend this piece for anyone who gets colder on the mountains, or for those brave enough for the -30 Celcius days on the hill!"

To buy: (top) $110, smartwool.com; (bottom) $110, smartwool.com

Best Silk Option: L.L.Bean Silk Pointelle Top & Bottom

These ultra-thin silk base layers from L.L.Bean are fitted to help lock in body heat, and shoppers say the pointelle-knit material on both has enough stretch that you can move around without feeling constricted. There are three colors to choose from, and the thermal underwear pieces come in regular, petite, and tall sizes. The silk top and bottoms are sold separately, which makes it easier for some people to find the right fit. One customer wrote, "I purchased the long sleeve scoopneck and the pants. Love them both and would purchase again. They feel good against my skin and most importantly, keep me warm!"

To buy: (top) $55, llbean.com; (bottom) $55, llbean.com

Best Lightweight Option: ViCherub Thermal Underwear Set

Thousands of Amazon shoppers love that this ViCherub thermal underwear set is super lightweight, so it keeps them warm without the bulk. Not only is the cozy set lined with fleece, but it's also breathable, stretchy, and feels silky smooth, according to customers. Plus, there are 11 different colors and prints to choose from, so you shouldn't have any trouble finding an option that suits your style. "The texture of the thermal wear is very soft," said one customer. "It was very comfortable and did not irritate my skin at all. I also like that it's very lightweight without sacrificing its comfort. It also provided great insulation against the cold."

To buy: from $20, amazon.com

Best One-Piece Option: Follow Me Thermal Onesie

This cute thermal onesie is great for both lounging around the house and layering under bulky winter clothing. Shoppers love the Henley neckline — which allows them to unbutton the onesie if they start to get too warm — and the “soft and comfortable” cotton/polyester blend material. “I purchased the thermal onesie for Christmas and I loved it so much that I had to order another one,” said one reviewer. “The fit was perfect, the thermal onesie is comfortable, it keeps me warm and the onesie is so cute. I am going to order additional thermal onesies for my kids. I am a big fan of these thermals”

To buy: $25, amazon.com

Best Men’s Thermal Underwear

Best Overall: TSLA Thermal Underwear Set

With over 4,500 five-star ratings, this TSLA thermal underwear set is one of the most popular men’s options on Amazon. Both the top and bottom are lined with fleece for added warmth, while their outer layers are made with silky smooth microfiber material that’s perfect for layering pieces on top of. Available in 30 different styles, including solid colors and camo print, the pieces are moisture-wicking and stretchy. “Nice warm base layer,” said one shopper. “Just took a walk in 25 degree calm weather and felt nice and comfortable the whole walk (about 20 min outside). The material is suuuuper stretchy and hugs your whole body. Now I’m inside and just wearing it as a shirt I'm also not sweating to death. The material really breathes well and I’ll be more than happy to buy two more pairs.”

To buy: from $22, amazon.com

Best Affordable Option: Rocky Thermal Underwear Set

Starting at just $10, this set from Rocky proves you don’t need to spend a ton of money for a quality pair of thermal underwear. A number of shoppers say the moisture-wicking base layer is super comfortable and warm without being itchy or scratchy, like some other thermal underwear is.. “My brother loves these,” wrote one reviewer. “He wears long johns all winter. He has quite a collection and these are by far his favorites. He said they are very warm and very comfortable. Now if anyone can tell me how to get him out of them and into the washing machine I would be ever so grateful. If you are a fellow long John lover you will love these.”

To buy: from $10, amazon.com

Best Wool Option: Smartwool Merino 250 Wool Base Layer Top & Bottoms

These ultra-warm wool base layers by Smartwool will keep you dry and warm as you partake in all kinds of outdoor winter activities. In addition to being super soft and comfortable, the Merino wool pieces are also odor-resistant to keep you smell-free. Both pieces are made with flatlock seams, which is great for layering since it helps minimize chafing. “I mainly wear this base layer while hiking, camping, or when I want the best balance between warmth, comfort, and breathability. It’s amazing how it doesn’t retain odor and how fast it dries. Most of all, it provides excellent warmth,” wrote one customer.

To buy: (top) $100, smartwool.com; (bottom) $110, smartwool.com

Best Silk Option: L.L.Bean Silk Underwear Top & Bottom

If you are a fan of silk thermal underwear, check out these popular options from L.L.Bean. The crewneck shirt is a great layering base that won’t show under most sweaters or top layers, while the slim-fitting bottoms aren’t bulky when worn underneath jeans, work trousers, and ski pants, according to shoppers. Both pieces are machine-washable but should be dried flat. “My husband loves these shirts,” said one reviewer. “He wears one from October through March, and it keeps him comfortable all day, indoors and out. There really is nothing like silk for warmth with breathability. We follow the label laundering instructions, and the shirts last 2-3 years. Well worth the price!”

To buy: (top) $50, llbean.com; (bottom) $50, llbean.com

Best Lightweight Option: Thermajohn Thermal Underwear Set

Nearly 12,000 Amazon shoppers gave this thermal underwear set a five-star rating because it’s lightweight, comfortable, and super warm. Both the top and bottom pieces are made from a silky smooth polyester/spandex material that provides enough stretch for full mobility. Even better, they’re breathable and odor-resistant. “Lightweight and excellent insulation for cold weather,” said one shopper. “My husband used the Thermajohn underwear long john set for our recent trip to Utah over Christmas. Temperatures were anywhere from 16 to 25 degrees. They kept him warm walking around catching glimpses of grandkids skiing for hours at a time.”

To buy: from $23, amazon.com

Best One-Piece Option: Duofold Thermal One-Piece

While most modern thermal underwear is sold in sets of tops and bottoms, they were originally designed as one-pieces, like this Duofold style. Wearing a one-piece base layer will keep you even warmer than separates since there is no gap for wind or cold air to get in. This option is popular among thousands of Amazon shoppers because the buttons go all the way down the front so it’s easy to put on and remove, and it has a rear fly opening for added convenience. One shopper said it’s “perfect for winter lounging” before adding, “I have three of these. I wear them around the house and sleep in them. We keep our house temp at 68 degrees. These are warm and comfy to wear in the winter and the flap is easy to open and close for access in the bathroom.”

To buy: from $37, amazon.com

Love a great deal? Sign up for our T+L Recommends newsletter and we'll send you our favorite travel products each week.