Last updated January, 2019: We’ve added new picks for 2019. Prices and links have also been updated.

Base layers need to do three things in order to perform well in the outdoors. They need to keep you warm through insulation, they need to breathe well during aerobic activities, and they need to wick moisture away from your body and allow it to evaporate. While your good ol’ waffle-style long johns might be comfortable and cozy near the fire, they no longer cut the mustard when it comes to modern needs. Merino wool, synthetic materials and a host of alternatives are better designed to accomplish all three objectives well, and they can be relied upon to do the job when you need them most.

Contributions by Tanner Bowden, Meg Lappe and AJ Powell.

Merino Wool

Natural Fibers that Shake the Scratchy Wool Stigma

Merino wool is the gold standard in base-layer materials. Its fibers are naturally antimicrobial, so they fight the stench that occurs after a few days on the trail, and the fabric is great at regulating temperature, making it usable in multiple environments. It also breathes well and wicks moisture away from your body to keep you dry.
From left to right
Bergtagen Woolmesh Sweater by Fjällräven $160 $120
Bergtagen Longjohns by Fjällräven $140 $105
Merino 150 Base Crew by Smartwool $80
Merino 150 Base Layer Bottom by Smartwool $75
Tech Top Long Sleeve Half Zip by Icebreaker $120
Bodyfitzone 260 Zone Leggings by Icebreaker $120


High Performance at an Affordable Price Point

Synthetic materials pack a big punch at a low price point. While they tend to pick up a stench easier than other materials, they do the trick of keeping you warm and wicking moisture away quickly. An easy solve for this is a blend of all-natural and synthetic materials (like the Patagonia picks in here). They’re also highly breathable, and after purchasing, they leave a little bit of extra cash in your wallet for something like a nice pair of hiking boots or new goggles.
From left to right (lightweight to heavyweight)
Sopris Long Sleeve by Corbeaux Clothing $80
TJ Pant by Corbeaux Clothing $75
Capilene Air Crew by Patagonia $129
Capilene Air Bottoms by Patagonia $129
UA Base 4.0 Crew by Under Armour $85
UA Base 4.0 by Under Armour $85


From Yak Wool to Bamboo

Recently, many manufacturers have started making base layers out of alternative materials. The below examples include bamboo wovens, yak wool and silk. They offer similar performance to merino and synthetic materials, but also offer other benefits, such as sustainability (as with bamboo fiber).
From left to right
Featuring yak wool:
Shola 230 Crew by Kora $145
Shola 230 Leggings by Kora $145
Featuring bamboo:
Crewneck Top by Bambool $70 $60
Men’s Legging by Bambool$60
Featuring silk:
Silk Underwear Crewneck by L.L.Bean $50
Silk Underwear Pants by L.L.Bean $50

One Piece Suits

Channel Your Inner Ninja

Onesies are a great way to keep warm on super-cold days. Even if the material is a lighter weight than you would typically wear on a cold day, the one-piece construction retains heat better than a top/bottom combo, so it’ll keep you plenty warm. As a bonus, they make great Halloween costumes.
From left to right (coolest to warmest)
Merino Ninja Suit by Airblaster $200 $160
Supermons 3/4 One Piece by Mons Royale $200 $160
Super One-Piece by Norrona $219

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