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Which men’s thermal underwear bottoms are best?

Spending time outside is good for the body and soul, no matter the weather, but this only holds true if you aren’t wet, cold and miserable. Men’s thermal underwear bottoms provide a base layer of warmth to build on, keeping you toasty and dry in the chilliest conditions.

Fruit of the Loom Men’s Classic Midweight Waffle Thermal Underwear Bottoms make a perfect bottom layer under heavier pants but also do double duty as cozy pajamas back at the lodge. 

What to know before you buy men’s thermal underwear bottoms

Union suit vs. bottoms only

Men’s thermal underwear bottoms can be purchased in two different styles: a union suit or bottoms only, often as part of a matched set of thermal underwear.

A union suit is like a grown-up onesie, a one-piece garment with buttons up the front. Old-fashioned union suits may have a flap in the back to make using the bathroom easier, but more modern styles don’t feature that flap. This means you’ll need to strip down to the skin when nature calls. 

Separate men’s thermal underwear bottoms are easier to layer. You can also keep the top half of your clothing on if you need to use the bathroom.


Thermal underwear can be found in four basic materials.

  • Wool: Merino wool long johns are traditional, and for good reason. They keep you warm even when they get wet, and the fabric is breathable and lightweight. Some people are sensitive to wool and may find these too itchy. 
  • Cotton: Cotton underwear seems like a good idea until you start sweating or it gets wet. The fabric holds moisture against the skin and can leave you feeling even more chilled. Cotton is best reserved for lounging and relaxing, not for working up a sweat in winter weather. 
  • Silk: This soft, luxurious fabric feels great and is an excellent lightweight layer. Silk does not remove moisture from the skin as effectively as other fabrics, so reserved these for light activities only. This fabric also traps odors, so you’ll need to wash it after each use. 
  • Synthetics: Synthetic fabrics like polyester, nylon, spandex and Lycra are incredibly durable and easy to care for, and they perform well under tough conditions. If you are active in extremely cold weather, their heat-retaining and moisture-wicking properties will serve you well. 

Intended use

Select different thermal underwear bottoms depending on what you’re doing. Lounging and working or playing outside require varying weights and types of fabric. The price of long johns varies wildly, so if you’re just relaxing on the couch there’s no need to shell out $100 for a pair of stretchy lounge pants.

What to look for in quality men’s thermal underwear bottoms


Those who are active in winter are just as prone to sweating as those who only take it outside in the summer. Moisture-wicking thermals remove sweat from your skin to keep you dry and warm. 

Flat seams and gussets

Flat inseams help prevent chafing and rubbing as you move. Look for men’s thermal underwear that has a gusseted crotch as well, designed for both support and comfort. 

Ribbed, tapered cuffs

Ribbed, tapered cuffs keep the heat where it belongs — next to your body. Additionally, ribbed cuffs can be easily tucked into your socks to prevent snow from coming in contact with your lower leg. 

How much you can expect to spend on men’s thermal underwear bottoms

From plain cotton, lightweight thermals to upscale silk long johns, expect to spend $10-$100. 

Men’s thermal underwear bottoms FAQ

How do you select the best weight?

A. The weight of the fabric you select depends on the activities and the weather.

  • Ultra lightweight: Ultra lightweight fabric is best suited for activity in the early fall and late spring. They are best used for moisture wicking and not as much for heat retention. 
  • Lightweight: Lightweight thermals provide heat and keep you dry during exercise in moderately cold temperatures. 
  • Midweight: When the wind picks up and the mercury drops, reach for your midweight long johns. These are highly versatile and appropriate for all kinds of outdoor activity. 
  • Heavyweight: Experiencing sub-Arctic temperatures or considering vigorous activity in snow? Heavyweight thermals are the best bet. 

How do you know if they fit?

A. Men’s thermal underwear bottoms walk the line between just tight enough and a little too snug. You want them to feel comfortable but be form-fitting to trap heat against your skin.

What are the best men’s thermal underwear bottoms to buy?

Top men’s thermal underwear bottoms

Fruit Of The Loom Men's Classic Midweight Waffle Thermal Underwear Bottoms

Fruit Of The Loom Men’s Classic Midweight Waffle Thermal Underwear Bottoms

What you need to know: These machine-washable thermals are warm and durable. 

What you’ll love: There are no tags in these. The poly-cotton blend wicks away moisture and holds warmth on the coldest days. The cuffs are tapered to prevent riding up. They are available in three colors and packs of one or two pairs. 

What you should consider: Order carefully. These run small. 

Where to buy: Sold by Amazon 

Top men’s thermal underwear bottoms for the money

Indera Men's Traditional Long Johns Thermal Underwear

Indera Men’s Traditional Long Johns Thermal Underwear

What you need to know: These are available in sizes up to 6X.

What you’ll love: The ribbed cuffs and elastic waistband are comfortable. The cotton-poly waffle knit traps heat and wicks moisture. These are best for low activity in mild weather. Choose from four colors.

What you should consider: The elastic in the waist stretches out over time.

Where to buy: Sold by Amazon

Worth checking out

Duofold Men's Midweight Wicking Thermal Pant

Duofold Men’s Midweight Wicking Thermal Pant

What you need to know: These perform well even with vigorous activity. 

What you’ll love: Flat seams reduce rubbing these comfortable cotton polyester thermals. They are machine-washable and come in four colors. Two extra layers of knitted fabric increase warmth. 

What you should consider: These are sized for a tall, slim build, so if that’s not you, you may not find these pants as comfortable.

Where to buy: Sold by Amazon


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Suzannah Kolbeck writes for BestReviews. BestReviews has helped millions of consumers simplify their purchasing decisions, saving them time and money.

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