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Whether you head outdoors for work or play, thermal underwear is your first line of protection against cold winter conditions. A first layer of long underwear allows you to customize your comfort in changing conditions by adding or removing outer layers. And is there anything more relaxing than chilling out inside on a cold winter night in a fleecy, thick pair of long johns? Just add hot cocoa, and you may never leave the sofa. Check out our guide to the best long underwear for any activity—whether you’re braving the cold or hunkered down by the fireplace.

Best Pair

A matching top and bottom ensure both comfort and long-term warmth. Thermajohn

Modern materials in long underwear not only trap and hold heat effectively, they also help move moisture away from the skin so you won’t feel clammy—which robs heat from your body once you stop moving. Many sets are made with high-tech treatments that absorb odors for long-lasting wear.

Active Wear Winner

Holding body heat close to the skin requires a solution-oriented design. The waffle-weave fabric knit provides insulation along with tiny micro-channels that allow moisture to wick away from your body. Carhartt

Keeping you warm is just one requirement of the best long underwear. Comfort is a close second. Look for an extra layer of care in the construction of thermal underwear. Flatlock seams and tagless labels will cut down on chafing and itchy discomfort, while contoured seams will boost the garment’s stretch for active movement.

Skin Friendly

Built with a double-layer construction, the microfiber exterior slides easily under clothing, while the fleecy interior is soft to the touch. ViCherub

Super-comfy long underwear is something you’ll reach for time and time again, whether you’re lounging at home or headed to the outdoors. You’ll definitely want to choose items that you can throw into the washer and dryer over and over, and not worry about them shrinking or losing their shape.