Best Thermal Underwear For Hunting – 2021 Buyer’s Guide

| Last Updated June 2, 2021

Sometimes it can get really chilly when you’re out hunting in the early morning or winter months. What better way to keep yourself insulated than to wear a pair of thermal underwear. This underwear is designed to keep you insulated.

However, there are certain features of the underwear that will maximize the effectiveness of the heat retention.

This article will discuss the various products on the market and their benefits and disadvantages. We’ll also mention what exactly makes a great pair of thermal underwear.

Comparison of the Best Thermal Underwear For Hunting

  • Full body set
  • Stretchy material
  • Thin regulatory layer
View Latest Price →
  • Very durable with reduced rubbing
  • Fabric is moisture-wicking and breathable
  • Offers wearer a comfortable long-term fit
View Latest Price →
  • Odor resistant
  • Ultra-soft polyester
  • Two piece thermals
View Latest Price →
  • 100% Cotton
  • Two layer thermal
  • Long-sleeved one piece
View Latest Price →
  • 100% cotton
  • Thick elastic qualities
  • Can be machine washed
View Latest Price →
  • Machine washable
  • 100% Merino wool
  • Wool is some of the softest material on offer
View Latest Price →

What is Thermal Underwear?

You lose body heat mainly from evaporative cooling which is when your sweat will cool you down by drawing heat energy away from your body. The thermals will draw the sweat away from your skin which minimizes the evaporative cooling process. The best materials for this would be Wool, Wool-Bamboo blends and synthetic fabrics like an acrylic.

Why You Should Use Thermal Underwear While Hunting

There are many benefits to wearing thermal underwear while hunting, the following section will discuss this topic in more depth by mentioning the main benefits.

Keeps You Warm

One of the main benefits of using thermal underwear while hunting is that they keep you warm during the winter months or cold mornings. Being cold is a huge problem for hunters that like hunting animals that are active during the winter. It’ll also mean you won’t suffer from that bulky feeling from wearing too many layers if you’ve got one great solid layer.

Decreases the Chance of Illness

A big problem that these thermals solve is that if you sit in your own cold sweat for too long you’ll develop a cold or something more serious. By absorbing your sweat, these thermals greatly lower the chance of catching the common cold. Meaning you can live to hunt another day.


How many times have you worn a pair of underwear and then some heavy hunting pants over it and they’ve started to rub up the wrong way? Too many times. However, thermal underwear will be able to adjust and attach themselves to suit your body shape so that this problem will never happen again. You’ll be snug as a bug in these pants and you’ll never regret it.

How to Choose Thermal Underwear

Like all great products, there are different features that will allow each to stand out and come off as unique, ultimately giving them an advantage. The following section will discuss what features you should be looking out for that’ll make the underwear some of the best.


The different material that’s used in certain thermal underwear will offer a variety of benefits and downsides. Mostly all thermal underwear is made from synthetic fibers such as spandex, polymer, nylon or polyester, these are great for cool environments.

However, natural fibers are a lot more effective at keeping you warm that these synthetic ones. The most widely used natural material is cotton as this is a great insulator and is really comfortable. Sometimes, natural is better.

Duofold Men's Mid Weight Suit - Inside Layer: 100% Cotton; Outer Layer: 65% Cotton, 25% Merino Wool, 10% Nylon Outer Layer


Another feature that is more important than the material is how many layers your thermal underwear has, the more layers the more resistant it is to cold weather. Some products might only have a few thin layers which are great for when you’re in cool temperatures.

However, thick and plenty of layers will allow you to hunt in the coldest of temperatures. This feature is more important than the material in terms of retaining body heat.

Breathability and Comfort

If you’re trying out your new thermal underwear, you want it to be as comfortable as possible. One way to see if it’s the right thermal for you is to understand how you feel in them. It shouldn’t make you feel hot or sweaty, you should feel warm and comfortable, if you’re sweating a lot, this means that the material can’t breathe because the thermal is too tight on your body. Ensure that the material doesn’t cause any itching or discomfort as this will cause you more hassle than it’s worth in the long-run.

Review of the Best Thermal Underwear For Hunting

This is the most important section of our article as this is where we can discuss the various thermals on the market that we believe to be the best. We’ll talk about their features, pro’s and con’s and give you an honest opinion of each.

Best Overall:
Men Thermal Performance Underwear by Outland

Men Thermal Performance Underwear Set by Outland; Base Layer; Soft Fleece; Warm Long Sleeve Shirt and Long Johns


  • Elastic
  • Full Body Set
  • Microfiber Fleece
  • Keeps You Warm in Cool Conditions


  • Not as Effective During Winter

This top and bottom thermal set is great for any hunter that is looking for full thermal protection rather than just underwear. Perfect for cool conditions, the polyester material provides you with a thin and lightweight layer that acts as a second skin because of its elastic quality which will allow you to be just as flexible as you were before.

The material successfully draws the moisture from your skin so that it insulates your body and keeps it dry. The full kit is easily washed and won’t shrink like many other products of this kind do. The microfiber fleece will effectively replicate that soft, natural cotton feeling against your skin.

Bottom Line

This product will be able to keep you warm during those cold mornings hunting, the early bird always catches the worm. However, the bird needs to be warm. The microfiber fleece is what provides that extra comfort which is a cloned feeling of soft cotton.

The polyester material will successfully act as a protective and insulative layer by drawing out the heat and absorbing any sweat. The only real downside to this product is that the hunter won’t be as warm during the freezing winter months because of the short, synthetic fibers.

CL convallaria Thermal Underwear Set

Thermal Underwear Set Winter Hunting Gear Sport Long Johns Base Layer Bottom Top Midweight Grey M


  • Super lightweight and cozy to carry
  • Easy-to-reach pockets available in the pants
  • Provides the utmost warmth at lower temperatures
  • Fleece lining on the pant maximizes its warming capability
  • Package includes a full-sleeved t-shirt and a long, close-fitted underwear


  • Pants can be too long for short-heightened, obese individuals

What Recent Buyers Report

Customers expressed an immense love for this thermal wear. According to them, it exceeded their expectations and didn’t cause any irritation to their skins. Moreover, its fabric impressed a lot of people and proved to be successful in resisting the coldness. All in all, people enjoyed using this pair of thermal underwear.

Why it Stands Out to Us

Made of 88% polyester and 12% spandex, this set of thermal underwear works excellently in chilled weather. It not only insulates body heat well but also enhances muscle movement through its four-way stretchability.

It offers outstanding breathability, meaning you don’t sweat unnecessarily, and it doesn’t stay wet for long. Instead, it instantly dries up and prevents the penetration of both UV rays and winds.

Bottom Line

In order to prevent the escape of heat, this set of long underwear has been manufactured from 88% high-quality polyester and 12% spandex. Its material promotes air circulation while keeping up with optimum insulation. Hence, this can be the ideal partner for hunting in cold weather.

Best for the Money:
Thermajohn Thermal Underwear


  • Flexible
  • Soft Polyester
  • No Bad Smell Stains
  • Argan Oil Makes it Soft


  • Not a Great Absorber

The fibers of this polyester two-piece are woven with argan oil which gives it the super soft feeling as if it were cotton. The material is also stretchable which means you’ll benefit from the same flexibility as you would without it on.

Acting as an effective barrier between you and the cold, the fibers will trap any body heat you produce which makes you feel as warm and comfortable as you need to be on those early cool mornings. If you find yourself sweating too much after a lot of walking you’ll be happy to know the material is also odor resistant.

Bottom Line

There are many benefits that come with this product, the main attraction being that the soft polyester is also finished with argan oil which gives it that extra soft feeling, perfect for sensitive skin. If you begin to sweat you’ll benefit from the anti-odor stain material, you could be walking for hours and still not smell a thing.

Another benefit of this two-piece would be the flexible material which allows for complete movement and no limitations. The only downside is that when you sweat it won’t be able to absorb it as well as natural fibers therefore you could start to get rather damp after a while of sweating, this would also mean you’d start to develop a cold sweat which could cause the cold or flu.

Thickest Thermal Underwear for Hunting:
Duofold Men's Mid Weight Suit

Duofold Men's Mid Weight Double-Layer Thermal Union Suit


  • Flexible
  • Cotton Material
  • One-Piece Dual Layer


  • Shrinks When Washed

The first cotton thermal product on the list, cotton is a great feature for any thermal product because it offers both great comfort and is a brilliant insulator. The two thermal layers is what will keep you warm during not only the cool mornings but the freezing winter months, this is something that no synthetic material would be able to properly accomplish.

The outer layers are also made partly from Cotton, Wool and Nylon. You’ll also be able to machine wash this product without sacrificing any of the beneficial natural materials. The stretchy one piece won’t limit your movement whatsoever and will continue to give you that flexibility that you need when hunting.

Bottom Line

The best material you could use when hunting in thermal underwear would have to be either Cotton or Wool, both materials offer some great warmth and can be really comfortable, thankfully this product is made from both. The one piece thermal is a dual layered product that will keep you insulated not only in the cool mornings but the freezing cold winter months, something that is rarely replicated by synthetic materials.

You’ll also benefit from a full range of movement because of the flexible and stretchy abilities. The only downside with such a product would be that it shrinks a little when you machine wash it. However, it should stretch back into shape once you wear it again.

Most Durable Thermal Underwear for Hunting:
Carhartt Men's Legging

Carhartt Men's Base Force Cotton Super-Cold Weather Bottom


  • Warm and Soft
  • Super-Thick Elastic
  • Machine Washable


  • Top Half Isn’t Provided

Hunting during winter can be painful when you think your legs are going to fall off from the cold. What better way to fix that than with a pair of extremely durable and thick thermal leggings.

This pair is made from 100% cotton which is well-known for retaining your body heat to provide you with a comfortable and warm feeling when hunting. One of the downsides of most cotton is that it can’t be machine washed, unlike this product which will easily stretch back once worn after being washed, thanks to the elastic features.

Bottom Line

These comfortable and warm leggings will help you survive the horrible, freezing winters by insulating your legs and absorbing the sweat which helps regulate your temperature more effectively. The machine washable leggings will shrink when washed but will spread back out once they’ve been worn again.

The super-thick elastic will also ensure that you’ve got complete control over your movement and you won’t be limited in any way. The only downside is that the top half isn’t provided with the purchase unlike every other set that’s featured on the list.

Editor's Pick:
Minus33 Merino Wool

Minus33 Merino Wool 706 Kancamagus Men’s Midweight Bottom - No Itch Renewable Fabric


  • 100% Wool
  • Super-Stretchy
  • Machine Washable
  • Perfect Range of Movement
  • Can be Used During Spring, Winter or Autumn


  • No Top Half Included

One of the two most widely used natural materials are either cotton or wool, the latter being the softest and probably the most comfortable. So, you’ll be happy to know that this is 100% Merino wool. The special, easy-care technology means that the fibers are machine washable and this won’t negatively affect the material itself.

The fibers are also able stretch and provide you with perfect range of movement and there is a guarantee that you won’t ever be limited in your movement because of these super-fibers. These leggings can also be used during the coolest temperatures of the year, like Spring, Winter and Autumn.

Bottom Line

There are many benefits that come with these thermal leggings, the main attraction being that you can use them throughout the majority of the year excluding summer of course. They’re also machine washable which is helpful as the effectiveness won’t be sacrificed.

The super-stretchy material will ensure that you’ve got a full range of movement which is really crucial for when you’re hunting. The only downside with this product is that there’s no top half that’s included with the leggings like mostly every other product on this list.

Comparison Overview

Thermal underwear is intended to keep people warm and cozy when they go for outdoor activities like hunting, sports, workout, swimming, etc. in chilled weather. Not all of them fall into the same category. Factors like materials, way of use, and purpose of use draw a line of difference between every thermal underwear. Plus, they are not the only clothing item that can retain warmth. 

This section will highlight the possible similarities and differences between some materials usually used in the making of thermal underwear. It will help you in figuring out which type of fabric will be favorable to you. 

Base Layer vs. Thermal Underwear

A base layer is also a type of underwear used to keep the body warm. Like thermal underwear, it is also made from well-insulated materials. However, there are some differences too.  


Let’s discover how these two are similar to each other.


The fabrics used for making these two apparel are common. Both are made from wool, synthetics, or silk.

Purpose of Use

Both base layers and thermal underwear absorb sweat from your body and dry it up quickly. The former keeps the body dry and ensures temperature insulation. Likewise, the latter intends to evaporate the body’s excreted moisture while inhibiting heat transfer.


There is a very fine difference between these two products.

Wear Alone or as a Layer

Base layers act as innerwear to be worn beneath your main suiting while hunting, skiing, hiking, or running in cold weather. On the other hand, thermal underwear alone can be used since it gives sufficient warmth. But below freezing temperatures, you will need additional clothing besides thermal underwear.

Silk vs. Wool Thermal Underwear

The ideal material for thermal underwear depends on the weather requirements and skin’s comfort. For instance, woolen underwear will be the wrong choice at 20 degrees. Similarly, sensitive skin will find comfort in silk underwear. Let’s see how the two compare to each other. 


The properties that are the same in these two fabrics are as follows.

Feels Soft

Wool and silk, both give a very cozy and soft feeling to the wearer. None of the two cause an itchy sensation.


Silk threads are so dense and strong that it’s hard to tear them apart. Similarly, woolen thermal underwear is also reliable to use and lasts longer.


Silk and wool thermal underwear differ from each other on account of the following characteristics.

Silk Demands More Washes

Both absorb sweat efficiently, but silk shows white or yellow patches of evaporated sweat. This doesn’t happen in the case of thermal underwear made from wool. Therefore, silk thermal wear needs to be washed more frequently than woolen ones.

Silk Dries Faster

Since wool is knitted more closely than silk threads, woolen thermal underwear stays wet for a little longer as compared to a silk one.

Cotton vs. Polyester Thermal Underwear

Some people prefer a sweat-absorbing fabric in thermal underwear, while many look for something other than wool or silk. Such people can fulfill their needs and wishes by selecting from cotton or polyester underwear.


Here, we will discuss the factors that make these two alike.


Both cotton and polyester thermal underwear are exceptionally lightweight. Moreover, it’s easy to wash the dirt off both kinds of outfits.

Absorbing Tendency

Both possess awesome and almost an equal potential to absorb moisture. Therefore, they are ideal for those who sweat insanely. 


Now, let’s take a look at the differences between the two. 

Change in Size

Some fabrics exhibit either drastic or minimal change when soaked in water for the first time, and cotton is one of those. Thus, cotton thermal underwear shrinks a little after the first wash, while polyester one remains intact.


Thermal underwear are an important part of a hunters clothing kit, they keep you warm and comfortable and safe from the cold. However, these benefits can only be experienced if you’ve chosen the right features or qualities which we’ve kindly provided above. If you follow this guide, you’ll be sure to find the best pair on the market.

People Also Ask

Some people must be wondering about the use, types, or advantages of thermal underwear. Thus, we decided to cover a few most discussed topics and answer some questions the majority of hunters usually have.

Is Thermal Underwear Necessary?

Yes, for sure! When you head out to hunting, hiking, workout, running, or skiing in cold weather, your ordinary sports gear alone will not be enough to provide the desired warmth. In that situation, thermal underwear becomes essential. If a person does not use it, it will be difficult for him to move around freely in freezing temperatures.

Should Thermal Underwear Be Tight or Loose?

Thermal underwear would be useless if it is not close-fitted. Loose thermal wear will ease the transfer of heat. Not just that, it will also sway on every move and will distract your hunting activities. On the other hand, thermal underwear should not be overly tight, or else it will restrict blood regulation.

Can I Wear Thermals as Leggings?

Well, it depends on the design and color of the thermal. If somebody intends to use it as casual leggings in the future, he can do so. Thermals come in various designs; some of them are made specifically for a certain activity. Thus, it’s better to go for products that can go well on any general and casual occasion.

How Does Thermal Underwear Work?

Basically, the fabric and design are responsible for functionality. Thermals made from wool, silk, polyester, or cotton can work as absorbents. Thermal underwear will be able to keep you warm during the cool weather, depending on how many layers and the material used it’ll keep you warm even in the coldest months of the year. It’s also a more comfortable alternative to using normal underwear. In addition, the elasticity and skinny cuts of thermals mold the outfit to your skin so you can jump, run, sprint, and hide with ease.

What is Thermal Underwear Made Out of?

There are many materials used for making thermal underwear. Some of the most common fabrics are polyester, nylon, spandex, wool, rayon, and cotton. 

Many companies combine more than one material in different proportions for producing thermals of the best quality. For instance, the blend of polyester and spandex turns out to be an exceptionally durable end-product.

What is the Best Thermal Underwear Material?

The best thermal underwear material would probably be natural cotton, it insulates you the best and is also really comfortable. The reason why it’s better at insulating is because the fibers are longer than that of synthetic fibers, therefore it traps the heat better.

How to Wear Thermal Underwear

First of all, wear your thermal bottoms. Then put on your thermal t-shirt. Make sure you are wearing the correct size. Extra tight thermals will pressurize your blood veins, whereas loose thermals will be uncomfortable to carry. 

Then put on your favorite sports apparel. And you are ready to go for a hunt.

How Many Pairs of Thermal Underwear Do I Need?

Thermal underwear stays very warm in cold temperatures. But at times, you may need more than one pair of thermal to survive inclement weather, so you can layer up another pair of thermals. Make sure the thermals you select have full sleeves and are breathable.

Do You Wear Underwear Under Thermal Underwear?

No, you wouldn’t wear underwear underneath your thermal layer, this would do the opposite of what it’s designed to as you’d sweat more with the extra layer between you and the thermal, this would get really uncomfortable. 

My name is Jeff and I have been hunting and fishing for over 40 years. I am an avid archery lover, bass fisherman, and all-around outdoorsman. Currently, I'm obsessed with elk hunting but I'm sure I'll move onto a different favorite soon. You gotta love hunting for that reason :) If you have any questions, or just want chat about your latest hunting score or big catch, you can reach me at Read more about Big Game Logic.