The right base-layer shirt is one of the most important parts of your outdoor training kit. A good one will breathe well so you don’t overheat, and it’ll also wick sweat away from your body quickly, preventing you from getting cold when you stop moving. I run hot and sweat like a pig, which is why all my favorite base layers are the lightweight, synthetic kind. While I’ve tested and loved dozens of wool options, the lightning-fast moisture-wicking capabilities of synthetics like polyester make them ideal for easy, everyday use, whether layered under a puffy in winter or as a stand-alone piece when it heats up (many quality shirts also offer great sun protection).
I’ve been testing base layers for Outside for five years now, both for the Buyer’s Guides and this column. Last year, when an editor asked how many base layers I had tried out, I answered, “Every one.” I was only partially joking. After hundreds of hours of testing, these are the five shirts that live in my closet year-round. For this column, I wore each of them on a backcountry skiing trip, during an early-morning skin up my local ski hill, on an hourlong run, and for at least one of the following activities: kayaking (worn under a drysuit), mountain biking, road biking, day hiking, and backpacking.
1. Northwest Alpine Black Spider Hoodie ($70)
I typically shy away from zippered, hooded base layers, preferring crewnecks or henleys because they chafe my chest less when I’m moving around a lot. And a hood can be annoying to stuff under other layers if I’m not using it. The Spider is special, though. The hood’s thin profile easily tucks into a jacket or slips under a helmet, while also protecting my chin and forehead from cold, wind, and moisture when the weather gets nasty. On top of being a star at the ski resort and on the skin track, beneath other layers on both occasions, I found this technical-yet-minimalist top perfect on its own during a 19-mile trail run and a 56-mile road ride.
2. White Sierra Ridge Stripe Crew ($50)
The Ridge Stripe takes the cake for the most comfortable base layer I’ve tested. With its brushed interior and ample stretch, I was sure it would bomb during hardcore outdoor sports, thinking I’d probably relegate it to my pajama drawer. I was so wrong. It wicked sweat well during a long day skiing Mount McDonald in the Siskiyous, as well as paddling the Scott River in Northern California. And it felt awesome underneath both my drysuit and soft shell. That said, the Ridge Stripe isn’t super durable, pilling the most of any of the base layers here and suffering a dime-size hole in the shoulder when it got caught in a drysuit zipper. Another downside: it boasts no odor-fighting treatment, so I had to wash it with Nikwax BaseWash ($10) after a spring of skiing and boating had it reeking of mildew.
3. Patagonia Capilene Lightweight Crew ($49)
While this utility player from Patagonia looks simple, it’s packed with nuanced details that make it perfect for hard-charging activities. Take the underarm gussets, which provided plenty of movement for mixed climbing in Chamonix, France. And the recycled polyester moves moisture so well that I’ve worn it on trail runs in 60-degree weather (where a T-shirt would have been fine) so I wouldn’t have to worry about sun on my arms. The subtle thumb loops keep the sleeves from slipping back under the sleeves of a midlayer or a shell and also keep my wrists covered. (One of the worst sunburns I ever got was on my wrists after a day skiing Mount Shasta.) Finally, the Lightweight crew is treated with Polygiene odor control, one of the best funk-fighting treatments on the market.
4. Myles Apparel Momentum Long Sleeve ($58)
I first wore the Momentum when I skinned up and skied Shasta last spring. Not once did I feel like taking it off, even through a massive temperature swing that ranged from a subfreezing 2:30 A.M. start to 70-plus degrees as we descended back to the car. That, combined with its refined good looks, is enough to make it one of my all-time favorites. The matte finish and athletic cut (without being too tight) give it a bit more dress-up potential while still looking sporty. Like the Patagonia, it has Polygiene, meaning I can get away with a few outings between washes.
5. Corbeaux Ajax Henley ($60)
While the Ajax has been on countless inclement ski tours and rainy trail runs with me, I really fell in love with it on a blazing-hot day of spring skiing. Being a henley, it allowed me to dump a good amount of heat when I opened the four snaps below the collar once I started sweating. On cold days, the extrathin polyester wicks moisture from my skin with the best of them, while also feeling cottony smooth. On top of that, the Ajax competes with the Momentum when it comes to style, thanks to the snaps and stripes. And it earns bonus points for being handmade in Minnesota.