Best Thermal Underwear 201​8
Buying Guide and Reviews

When you think of products that may improve your health, your underwear is probably not the first thing that comes to mind. Thermal underwear, however, has been shown to improve the health of heart failure patients and can improve health in general. This is because keeping your core body temperature consistent and not letting it raise or drop too much is an important part of having a healthy immune system, good circulation, and a powerful heart. So, while thermal underwear may not keep you from getting the sniffles this cold and flu season, it may help you to heal faster! While humans need clothing to keep warm when the thermometer drops below freezing, cold adapted animals are just fine: this is because their fur serves as a protective, insulating layer, trapping in their body heat for longer periods and keeping them from the cold. If you want the resilience and endurance of our four-legged friends, you may want to consider some winter thermal underwear this season.

Thermal underwear is usually long sleeved and long legged, and is an inner layer of clothing you can wear under your regular day clothing. It is especially useful during outdoor activities in the winter or even for daily use during the colder months. Some people even use them as extra soft, extra warm pajamas for sleeping cozy and tight in the winter months.

Once you have researched the benefits of wearing thermal underwear under your clothing, you may wish to purchase some for yourself. Thermals are not the easiest thing to purchase: because they are not something everyone thinks about, few people know what brands to look for or what is popular. There is also no a clear ranking online as to what is the best product, as different people prefer different brands and varieties.

Thankfully, this article will provide you with a list of the top ten most popular winter thermal underwear listings on, after we tell you everything you need to make the most informed decision possible when shopping for the warmest thermal underwear. We will first discuss the different types of thermal underwear typically available for purchase. Then, we will show you the most popular brands of thermal underwear online. Then, we will discuss the different features and types you should look for when making your purchase in our buying guide. Finally, we give you the top 10 rated products on for your convenience.​

Best Thermal Underwear 2018

1. Duofold Men's Mid-Weight Wicking Thermal Pant - Best Thermal Underwear 2018

The most popular thermal underwear on Amazon is Duofold Men's midweight moisture wicking bottoms, which are a double layered blend of 60% cotton and 40% polyester. The unique double layered fabric gives the warmth of three layers with the freedom of a single layer, and the cotton-polyester blend is designed for the softness of cotton with the performance of polyester. It does this by trapping warm air from your body between the two layers before it can escape into the frigid atmosphere. Champion’s Duofold fabric is specially designed to keep you warm and dry without feeling heavy, puffy, or bulky. It has a unique blend of synthetic and natural materials woven into a sleek, soft design that gives the best of both performance and comfort. This has the added benefit of looking sleek and smooth under your outer clothing.

These thermals are designed for the ultimate comfort as they have no itchy tags and a stretchy, moisture wicking waistband designed for easy, pull-on wearing. They also have flatlock, chafe-free seams and a convenient front fly. Designed to fit close to the skin, they still provide enough looseness to keep you comfortable during light activity in cold weather.

Duofold’s mid-weight thermal pants for men come in four different colors: black, white, navy and red. They also come in small, medium, large, X-large and XX-large. Customers on Amazon advise potential purchasers to consult the sizing chart carefully before buying, as some reported the bottoms run a little larger than they usually wear. They are also machine washable. Overall, Amazon reviews report that these thermal bottoms provide a comfortable, warm extra layer under their clothing. The price on Amazon is also a little more affordable than from the original manufacturer. Buy Duofold midweight moisture wicking thermal long underwear for simple, quality protection from the cold this season.

Duofold’s crewneck top is the companion piece to the mid weight bottoms above. Also for men, the cotton-polyester blend shirt will pair perfectly with a matching set of thermal pants. Like the other Duofold products, the unique double layered fabric gives the warmth of three layers with the freedom of a single layer, and the cotton-polyester blend is designed for the softness of cotton with the performance of polyester. They also feature flatlock seams for no-chafe comfort, as well as ribbed cuffs to keep the sleeves snug around your wrists. Because of the fabric and design, these thermals will feel light and clean even while providing the extra warmth you will need as the temperature drops. Like the other Champion products on our list, this Duofold top uses the intelligent dual layer fabric to trap your body heat (which is crucial in your torso and core area) close to your skin and keep you warmer for longer.

As above, Duofold’s mid-weight thermal shirts for men come in four different colors: black, white, navy and red. That way, if you would like to pair it with your Duofold mid-weight pants, they will go perfectly. This shirt comes in small, medium, large, X-large and XX-large sizes. Again, this shirt is machine washable. Amazon customers agree that this mid-weight thermal shirt is comfortable,

practical, and toasty warm. They even noted that Duofold products are much warmer and better made than other brands of thermal winter underwear. They did, however, note that the sizing can sometimes be difficult, so pay attention to the sizing chart. This product is the perfect match for Duofold’s mid-weight thermal pants above.

Carhartt’s 9.5-ounce, 100 percent cotton ring-spun knit fabric is designed for super cold days. The machine-washable, moisture wicking fabric is designed to be extra, extra warm. Using the classic waffle-weave pattern, these Carhartt thermal pants are in the heaviest weight that Carhartt can offer, guaranteed for maximum warmth. Amazon customers call them the warmest long johns they have found in a while, stating that they live up to the Carhartt brand, which supplies the sturdiest, best quality clothing for workers, sportsmen and athletes possible. The logoed elastic waistband, tagless collar label, and rib-knit cuffs on these thermal underwear pants provide a comfortable, stretchy wearing experience.

Carhartt’s FastDry® technology quickly siphons your sweat away from your body, cutting down on unpleasant wetness and also keeping you warmer, so you can remain warm and dry throughout your day. These winter leggings are also sturdy with reinforced stitching and stain-lifting fabric for easy cleaning. This Stain Breaker® fabric is designed to help the washing machine do its work better by keeping those tough spots from setting in.

Reviews on Amazon report a love for Carhartt as a brand and a love for this product in particular -- people who buy these long johns wear them to work all day in freezing temperatures, and stay up warm and dry. They do not slide around, and wearers hardly notice they even have an extra layer on. As a Carhartt product, these are a classic, quality pair of long johns that will do the job and do it well. Whether you are a hard working person, or even just wanting to lounge around in comfort, or both at the same time, Carhartt’s 100% cotton knit long johns will keep you the comfiest, warmest and driest it is possible to be.

This thermal set by CuddleDuds is for boys. It is perfect for sending them out on snow days for sledding, tubing, snowboarding, ice hockey, or building a snowman. These ClimateSmart® Core Polyester thermals would also make a great extra layer for school days when the temperatures are below freezing, and to prevent sniffles during cold and flu season. Their soft, lightweight interlocking fabric will feel smooth on the skin, and the thumb holes on the sleeves will keep the sleeves firmly in place, even during the most active play in mittens or gloves. The pants also have a functional fly, to save time when running in and out of doors for pit stops.

The 100% polyester fabric is silky, smooth, and comfortable, and Amazon customers reported that their kids enjoyed wearing these long johns for sleeping, as well. Because this fabric is light and breathes well, it will help trap body heat without getting too sticky or hot. The thermal underwear comes in five different colors: three solids and two prints. The solid colors are black, gray, and navy. The options for patterned prints are a large, funky gray, black and white camo and a whimsical and adventuresome blue and red striped pattern. Customers also report that the sizes run small, so check the size chart and consider going a size up if your son prefers a roomier fit. Your boy will feel good and stay warm wearing his ClimateSmart thermal underwear this winter.

Another Duofold product, this moisture-wicking thermal top for women is highly rated for its ability to keep wearers warm. Like the other Duofold products on this list, their women’s thermal shirt comes in a comfortable, breathable, 60% cotton 40% polyester knit fabric which is machine washable and has a built in a double layer for maximum protection from the cold. Meant for low impact activities, this shirt will keep you clean and dry during light exercise in cold weather, especially with the carefully sewn flat lock seams to avoid irritation and chafing on your skin.

This thermal shirt also has pointelle fabrication seams for added feminine detail, so it will fit to your form and look invisibly smooth under your outer clothing. The fabric itself is light and pliable, so it won’t be too bulky underneath. When you are wearing Champion’s Duofold dual-layer clothing, no one will be able to tell you have another layer on. That is, unless you want them to. It also comes in six different colors: white, black, frost, ice cake, berry delight and granite heather. Like other Duofold products, the neck is tag free with a printed on collar for maximum comfort and ease.

Amazon customers report that this shirt fit exactly as expected, washed well and kept them warm as

expected. One even stated that they purchased it for a trip to Antarctica and were extremely satisfied with the shirt’s performance. Users also felt that the shirt was soft comfortable, looked nice and had well-made details. Some even wore it for sleeping, as well as for everyday warmth. Duofold’s mid-weight moisture wicking thermal shirt for women is a wonderful way to stylishly, effortlessly, and comfortably keep warm and dry this winter.

Best Thermal Underwear Buying Guide

As you begin to look for the right set of thermal underwear for you, look through this handy buying guide to help you begin to think of the different options you may run across in your search for the warmest thermal underwear this season.

Sets And Separates

Some thermal underwear comes in two-piece sets: a top and a bottom. The top is usually in the form of a long-sleeved t-shirt, and the bottom standard full-length pants.

Thermal shirts tend to have a crew neck, so they cover as much of your skin as they can without showing over the top of your collar. Crew necks, too, can be good for making an extra, visible layer for fashionable wearing, as they are a medium height, swooping circle beneath the throat. Many of the options below have a tagless, printed label in the collar, keeping you from irritation and distraction as much as possible in your extra protective layer. Shirts often have a ribbed cuff around the wrists for extra warmth and to keep the sleeves firmly in place. Some models have a cut out for the thumb to serve this same purpose. Thermal shirts usually fit like a standard long sleeved t-shirt, depending on the size and cut; however, some women’s models have seams in the sides for a more flattering, feminine look.

While some may confuse thermal pants with leggings, thermal pants have a roomier, looser cut than leggings. However, they are not as loose as wide leg jeans. Depending on your size, the size of the thermals and the type of pants you wish to wear over them, they may be a great way to keep your legs extra toasty. Thermal pants usually have a ribbed cuff at the bottom of the ankles to keep them warm and provide extra protection where your shoes meet your outer layer--this is especially handy when wading through deep snow.

Whether you buy your thermals as a matching set, or only purchase one or the other, it is important to know what you are getting so you can get the warmest thermal underwear possible.


Most of theses products are some blend of cotton and polyester. Cotton, while soft, plush, and, dare we say, “cottony,” absorbs water quickly and holds it for a long time… not the best for staying dry when you sweat or in drizzly weather. Cotton is grown as a plant and spun into fibers, then knit into chunkier, plusher weaves.

Polyester, on the other hand, is a synthetic fabric that breathes well and dries fast, and was designed for and frequently used in athletic wear. It is also silky smooth and looks sleek and professional. The items on this list are all some blend of cotton and polyester, and are designed to give the best balance between the comfort and firm insulation of cotton and the cool, stretchy lightness of polyester.

A common type of fabric for winter thermal underwear is “waffle” weave, and it looks just like it sounds. This fabric is built of a system of interlocking threaded squares, forming a classic pattern that is both insulating and soft on skin. Some thermals may have a smoother, sleeker feel. You will want to consider the fabrication of the garment and your own personal preferences before making a choice on texture and weave.


For men’s thermal underwear, your color options are basically black, white, and navy. For women’s and children’s sizes, however, there is a wide variety of colors to choose from. From soft pinks to bright blues, you can purchase a color that will coordinate with your clothes if you choose to show off your layers, or to have a secret delight in wearing your favorite color in long underwear. Many brands also come in patterned prints, which are especially nice if you choose to wear your thermals as sleepwear.

Alright, now that you know the basics of how to choose the type that is right for you, let’s dive into the products that are available online.​

The Different Types Of Best Thermal Underwear

When it comes to buying thermal underwear, there is a pretty standard array of choices. Most of the differences you will need to consider will come in terms of fabric, size, and color. The vast majority of thermal underwear comes in the form of a long crew neck t-shirt and loose, legging-like pants. However, there are other variations and each one is packaged differently and with different features. Some people prefer a “union suit” which is the older, one piece long john underwear. Some people prefer to buy their thermals in a set or as separate pieces. You will want to consider some of these parameters as you peruse the list of products available online. First, however, let us turn to the most popular brands for sale.

The Different Brands Of Best Thermal Underwear


The most common brand on our list is Duofold, a subset of Champion and made by Hanes. Hanes, founded in 1901, is the largest marketer of basic apparel in the world. According to their website, over 90 percent of households in the United States today have Hanes products in them. This is due to their history of innovation, excellence and brand recognition. Hanes has dozens of subcategories worldwide, both at home and abroad. Based in North Carolina, Hanes is on the Fortune 500 list and is a global employer committed to social responsibility. Duofold products make up three of the ten on our top ten list, as Hanes products are reliable, affordable, and sturdy. Because Hanes specializes in intimate apparel, they are sure to provide the best basic innerwear available on the market. Duofold thermal underwear has the added benefit of being a quality innovative product that blends cotton with polyester -- they do not use heavy, itchy wool or even 100% cotton, which can be hard to dry out after it has gotten wet. Choosing a Duofold set of thermals will supply you with a steady, reliable option to keep you warm and dry this winter.


Carhartt is well-known for their sturdy brown jackets and overalls, but did you know they made other clothing items as well? Begun in 1889, Carhartt at first focused on providing railroad employees quality affordable apparel. Quickly expanding to the automotive industry, Carhartt later manufactured uniforms for World War I and women’s workwear for World War II. Later, the business expanding to hunting, active wear, women’s clothing, and fire resistant clothing. The famous “Chore Coat” is largely unchanged since it was developed in 1923. Since its inception, Carhartt has been committed to worker’s rights, especially for women and fair workdays. Their line of thermal under clothes is made of sturdy material that are moisture wicking, odor resistant, and easy to clean. Carhartt’s “Groundbreakers” program ensures that their clothes are suited to the needs of those who use them. For high quality, made-in-the-USA thermal underwear, look no further than Carhartt.

Best Thermal Underwear Wrap Up

So as you can see, if you are looking for an extra layer of winter clothing this season, consider buying yourself (or a loved one!) a set of winter thermal underwear. Wearing an extra layer may have health benefits, and at the very least will feel great. It also may serve as an extra fashion layer under your clothing and comes in several colors and styles to facilitate warmth with flair. Hopefully this article has demonstrated the ins and outs of purchasing your very own set of thermal underwear and provided you with the right links and information to choose from the ten most popular products on Now, go forth and be warm, comfortable, and dry during any winter activity, for daily work or even as you sleep.

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