If you're like us, the shirt you put on at the trailhead is the same on you're wearing at trip's end, even if it's a week later. So that one shirt better do it all, and do it all well: wick buckets of sweat, dry quickly, fit perfectly, control stink–and look flattering. After testing more than 40 of the latest baselayers, we've narrowed the universe down to eight top performers.
Fastest Drying [65–100°F]
ExOfficio ExO Dri (m) / ExO Dri Pointelle (f)
Don't blink, or you'll miss seeing this shirt wet. "It was raining off and on all day, and we didn't have jackets with us," said one tester after a hot hike in Prescott National Forest. "Whenever the drops stopped, my shirt was always the first to dry." The Dri-Release fabric (an 85/15 poly-cotton blend) is designed to suck moisture like a Hoover and transfer it to the shirt's exterior so it can evaporate more rapidly.
We liked the flatlock stitching and forward shoulder seams, which prevent chafing under a pack. Women raved about the pinprick holes on the Pointelle version, which significantly improve ventilation while adding a touch of style. Although the ExO fabric is chemically treated to resist odor, some testers said they were holding their noses after a few days of heavy sweating in this shirt. Also comes in long-sleeve. $34 (men's M–XXL), $30 (women's XS–XL) (800) 644-7303; exofficio.com.
Best Overall Trail Tee [55–100°F]
Icebreaker Tech T Ultralite 140
Wearing a wool T-shirt in the broiling desert is a bad idea, right? Well, after a 15-day spring trip in southern Utah when the mercury pushed above 90°F, our test crew begs to differ. "During the day I stayed cool, even when sweating under a heavy pack," said one tester. "Then at night, when temps dipped to the upper 40s, this shirt kept my core warm with only a wind shell over it."
Despite our testers' perspiration, this top was surprisingly stink-free at trip's end. It dried faster than any of the other wool tees we tested - about 20 minutes after being worn in a canyon pool on a hot, sunny day (drying time will be slower in humid climates). Fit is comfortably loose but not baggy. The shirt rebuffed thorny tamarisk and looked new even after a dozen-plus machine washings. $55; men's S–XXL, women's XS–XL (208) 726-1000;icebreaker.com.
Dale of Norway Baselayer
Fights nearly broke out when it came time for testers to rotate shirts - nobody wanted to give this one up. "It wicks well, and it's so soft it practically gives me tingles down my spine,” raved one tester. The reason is Dale's proprietary blend of Australian and New Zealand ultrafine merino, which after multiple washings didn't get stiff or scratchy as lesser wools tend to do.
Dale uses no chemicals in the wool washing and dyeing processes, and the antishrink treatment applied to the finished product is also chemical-free. Fit is roomy enough to layer a T-shirt underneath, and an 8-inch zipper on the mock turtleneck allows for venting. One bummer: You can't put it in the dryer, and some testers said it lost a bit of shape after line drying. $69; men's S - XXL, women's S - XL (800) 441-3253; daleofnorway.com.
Most Versatile [50–75°F]
Ibex Woolies Crew
"It's like there's a hidden thermostat inside," commented one tester on this top's outstanding natural temperature regulation. We stayed comfortable across a gamut of conditions, ranging from snow (worn under a shell) to a sunny 70°F. The 100% merino is as smooth and soft as a baby kitten; it wads up small enough to fit in a front pants pocket, yet provides as much warmth as a synthetic fabric twice as thick.
When the mercury rose, testers said the Woolies wicked and breathed like a second skin, and only started to feel hot in the upper 70s. Flat seams and a body-hugging fit make it comfortable under a pack. And thanks to wool's natural odor resistance, testers on extended backpacking trips reported that their bagels got moldy before their shirts started to stink. Also available in short-sleeved and sleeveless. $60; men's and women's S–XL (800) 773-9647; ibex.com.
Sweat Sponge [45–60°F]
Marmot Polartec Crew
"Wearing this Marmot crew on a sweaty hike is like using a towel to dry off when you step out of the shower," said one tester after a hard uphill backpack in the Grand Canyon. The stellar wicking action comes from an interior waffle pattern that disperses sweat, and a superfine polyester-Cocona fabric blend.
Cocona, made with activated carbon fibers from the insides of discarded coconut shells, has innate wicking abilities that we've found to work better than many synthetics. Its makers claim that it also has natural odor-fighting properties, but our jury is still out.
We put this shirt through the handful of washings that Marmot says is required to activate the carbon's antimicrobial action, then did some sniffing. Some testers gave it the thumbs-up; others said it was unusually stinky. It does provide good insulation for its weight, yet generally stays cool and dry under a shell. Testers liked the way the brushed fabric felt against their skin and how the smooth exterior slid easily under layers, but flagged it for excessive pilling. $45; men's S - XXL, women's S - XL (888) 357-3262; marmot.com.
Stink Fighter [50–65°F]
Mountain Hardwear eXtend Zip T
"Your campmates will thank you for wearing this shirt,” said one tester. He wore it for 10 days straight in southern Utah, and reported the odor at the end of the trip to be minimal - "just a hint of last night's garlic, which I can't really blame on the shirt."
The stink-fighting powers come from the fabric, VisaEndurance, which is embedded with silver ions to prevent bacteria from growing. Testers liked the pajamalike feel of the spun polyester. A mesh finish inside with thousands of pinprick holes pulls moisture away from the skin and helps the fabric dry quickly, while still insulating in cooler weather. And unlike other knit polyester tops, the eXtend did not snag on brush or abrade against rock. Fit is loose and long; some female testers reported that the sizing was too big. Also comes in featherweight. $55; men's S–XXL, women's XS–XL (800) 953-8375; mountainhardwear.com.
Most Durable [45–60°F]
Outdoor Research Sequence (m) / Essence (f) Zip Tee
"I wore this top caving and beat the hell out of it," wrote one tester. "Yet one spin through the washer and dryer and it was back to looking new." Its unique 88/12 blend of polyester and merino wool was one of the best in the test at keeping testers comfortable in that sweet spot from the 20s (when worn under a shell) to the mid-60s (worn alone). It also dried quickly and shrugged off stink, even after a week on the trail.
Fit is slightly roomy in the torso and the sleeves run a tad long, pleasing long-armed testers and those with cold hands. Also available in short-sleeve. $42; men's (Sequence) S - XL, women's (Essence) XS–XL (800) 421-2421; orgear.com.
Wicking Champ [30–50°F]
Duofold Varitherm Expedition Weight Zip Mock
"Cozy as my favorite blanket," said one tester after a rainy, snowy spring snowshoeing trip in the Sierra. The polyester-Lycra Varitherm has two layers of fabric sewn together, which boosts warmth and sucks up moisture like a two-ply paper towel. "I've never worn such a thick baselayer that wicks so well," said another tester.
The ample four-way stretch allowed us to reach out ("for ridiculous handholds,” wrote one climbing fanatic), and the neck zipper aided venting. It's versatile, too: Some testers used the Varitherm as an outer layer over a tee when backpacking in 40°F temperatures. Sizing gripe: The women's fit is too short in the torso and sleeves. $44; men's S - XXL, women's S - XL (800) 448-8240; duofold.com.