By Michael Lanza

Let’s admit it: We don’t always take our base layers as seriously and we do our outerwear and insulation—or packs, tents, boots and other gear, for that matter. But this under-appreciated first stage in a layering system for the outdoors really sets the table for how comfortable you’ll be. Base layers that don’t perform well probably won’t kill you, but misery isn’t a good companion. This is what we wear against our skin. It matters.

After much testing from the trails to the mountains to the gym year-round, the long-sleeve tops, T-shirts, shorts, underwear, and socks reviewed here are the best I’ve found for dayhiking, backpacking, trail running, climbing, and training. And over the course of a quarter-century of testing and reviewing gear, including the 10 years I spent as the lead gear reviewer for Backpacker magazine and even longer running this blog, I’ve learned how to distinguish the mediocre from the excellent.

Light- and medium-weight T-shirts and long-sleeve tops are the most versatile because you can layer them in a wider range of temperatures to keep you drier and cooler, but fabrics and design features of tops and shorts also affect their temperature range and the activities for which they’re comfortable.

Please leave any comments or questions about my picks for best base layers in the comments section at the bottom of this story. I try to respond to all comments. And you can support my work on this blog, at no cost to you, by making purchases through the affiliate links below—where you’ll also often find the best prices. Thank you for doing that.

Hi, I’m Michael Lanza, creator of The Big Outside. Click here to sign up for my FREE email newsletter. Join The Big Outside to get full access to all of my blog’s stories. Click here for my e-guides to classic backpacking trips. Click here to learn how I can help you plan your next trip.

What You Need to Know About Synthetic Versus Wool

We all know that synthetic fabrics wick moisture and dry quickly, while wool keeps you warm even once it’s wet. My experience with dozens of base layers is that both types keep getting better. Modern synthetics are getting lighter and more efficient at moving moisture. I wear lightweight synthetic base layers for high-intensity activities in warm temperatures, and midweight synthetics for moderate-intensity activities in cool temps. But synthetics can get sweat-soaked (leaving you cold on cool days) and stinky after many days of wearing and multiple washings.

Wool—which today often means Merino wool—keeps getting softer and more comfortable, and I find myself wearing it more often, for virtually any activity, in a wider range of conditions than I ever did before. It breathes as well as any fabric; doesn’t dry as quickly as synthetics, but keeps you warm, anyway; and won’t develop odors. But the lightest Merino wool tops aren’t always as durable as synthetics.

Today you can also find base layers that combine synthetic fabrics with wool—often Merino for its softness—to combine the strengths of both materials.

The Patagonia Capilene Cool Merino Tech Tee.
” data-image-caption=”Testing the Patagonia Capilene Cool Merino Tech Tee in Idaho’s Boise Foothills.
” data-medium-file=”″ data-large-file=”
Did you miss our previous article…