In early spring 2020, right as coronavirus was coming over the horizon, I was looking into the issues of climate change and what makes gear sustainable (or not). Thinking about apparel and the staples in my closet, I considered the fabrics—the oil-based synthetics, the organic cottons, the wool base layers and tees. Why aren’t we all wearing one hundred percent wool all the time, I wondered? It’s natural and renewable and its technical properties are amazing. Were it developed in a lab, it would be considered a miracle fabric.
Wool is all of those things, and I’ve come to believe that at least one wool technical t-shirt needs to be in everyone’s wardrobe. It warms when cool, cools when hot, looks elegant, and comes in nearly endless styles and colors. Ann Wiper, a vice president at Smartwool, told me over a Zoom call, “If you had 10 [clothing] things, the black merino tee would be a core component. Everybody in the world should have one.” For the record, she was wearing one as we talked.
Wool’s sustainability story, of course, isn’t that simple. (It never is.) A t-shirt constructed of wool alone faces challenges. If it’s too thin, you can poke your finger through it. It risks pilling. It might have no problem stretching but not bounce back properly (a feature called recovery). That’s why most wool tees, whether short- or long-sleeve, are blended with synthetics. They add durability, recoverability, and sometimes comfort. You certainly can avoid petroleum-based fabrics and wear 100 percent wool tees, but they are the exception rather than the rule.
Over the last year, I have wear-tested nearly 20 different wool tech t-shirts, in cool, cold, warm, and hot weather. I’ve run, hiked, and biked in them. I binged Killing Eve, Handmaid’s Tale, and Flight Attendant in them. I’ve used short- and long-sleeve models from ten manufacturers. And after all that use, I came to a conclusion, which surprised me: They’re all darn good. Going into this project, I expected far more differences to be revealed between brands and individual products over time, but in fact, no matter what their blend or maker, they all functioned extremely well across a variety of conditions and temperatures. Credit the wool itself, with some boost from the blended synthetics, but you can pick any one of these shirts and be happy. If you’re loyal to a brand, support them. You’ll be stoked.
The differences that do reveal themselves are primarily around fit, stretch, and fabric weight. The most athletic fits (defined as more body hugging) came from Arc’teryx, some of Icebreaker’s tees, Ortovox, and Tracksmith. Black Diamond, Duckworth, REI, and Smartwool tended to be in the middle, fitting like your favorite cotton tee. Beringia, Houdini, and Voormi were loose and airy. All shirts were tested in men’s medium.
The A2B T-Shirt is the archetype for wool tech tees: It looks and feels like a hearty cotton t-shirt, with the wool/polyester fabric weighing 150 grams per square meter, or twice the Voormi hoodie reviewed below. It’s more substantial, more midweight, and that extra thickness drapes nicely over your shoulders. Arc’teryx positions the A2B for “urban lifestyle with technical advantages,” which reads like a tepid endorsement of city use. In fact, it excelled no matter what sport I pursued, though it did it best in cooler temps. Note that I had no problems washing the short-sleeve version of this shirt, but with the long-sleeve I followed the care instructions and the sleeves shrank about ¾ inch in length.
Fabric: 50% polyester, 44% wool, 6% nylon. Care: machine wash cold, tumble dry low.
You know those classic waffle long johns, the kind you expect to see under a plaid flannel shirt on a lumberjack? Beringia makes a top just like that, the Diomede Merino Wool Long Sleeve Crew, except it’s 89 percent wool—and not only is it wool, it’s made of the softest wool of any shirts we tested. Indeed, I’d happily take a blanket of this wool, or better yet a onesie. The comfort is off the charts and so is the stretch.
Fabric: 89% wool, 11% polypropylene. Care: machine wash cold, dry flat.
BD touts its Rhythm Tee as the world’s “lightest technical wool shirt” thanks to a 95 grams per square meter fabric called Nuyarn. Its overall weight is 95 grams, too, which is 3.3 ounces, and yes, you notice that it’s so light. It is significantly wispier than REI’s Merino Midweight tee—different shirts with different intentions, but they make a fine comparison. Voormi’s fabric is nearly as light at 100/gsm, though the Black Diamond blends with nylon, not poly, and is significantly stretchier. The BD also had the fastest drying time, though the Voormi was a close second.
Fabric: 57% nylon, 43% merino wool.
Duckworth’s is an American story. Its merino sheep are raised on a Montana ranch and the fibers are spun, knit, and sewn in the US, too. And yet the price of the Vapor Tee is $65—at the low end of the shirts we tested, most of which were sewn in Asia. Its shape is nearly identical to the REI and Smartwool shirts below—the classic tee silhouette—and our only beef is that it has rather thick seams on top of the shoulders. Great for wearing around, less so with a backpack strap.
Fabric: 38% merino wool, 50% polyester, 12% bamboo. Care: machine wash cold, dry flat.
Over dozens and dozens and dozens of days of wear testing, without planning it, I wore one shirt far more than any others: Icebreaker’s Cool-Lite Merino Motion Seamless Short Sleeve Crew. That’s a mouthful for the name of the shirt that fit me the best and I liked the most. As I wrote above, every one of these shirts functions fantastically and were I to rate them I’d give them all 4.5 stars out of 5. But the Icebreaker had some intangibles that elevated it. First was the interaction between the shape and my body. The tight fit of Ortovox is great for cardio adventures, and the classicism of the Smartwool can make the workhouse of any wardrobe. The Icebreaker falls in the middle, with a slight taper from the armpits to the hem, that makes an athletic body look even better (especially in black).
Second was the fabric itself. A mix of merino and Tencel (a form of rayon derived from eucalyptus fibers), Cool-Lite weighs 155/gsm in this shirt, but feels markedly lighter and thinner than some of the 150/gsm tees I wore. It has an exceptionally smooth face that might even have you questioning whether it’s wool. My one complaint? I often wore the Icebreaker with a backpack or lumbar pack and it developed light pilling at the bottom of the spine. Ideally, no pilling. But for this shirt, I can live with it.
Fabric: 35% merino wool, 35% Tencel, 18% polyester, 12% nylon. Care: machine wash warm, line dry.
Ortovox makes no bones about the fact that its short- and long-sleeve tees are designed for athletic performance. The short-sleeves are short and shoulder-hugging, the better to display your guns if you got ’em, and the body hugs your torso like it hasn’t seen you since covid began. Logos tend to be bright and more visible—the black tee I wore had a lime-green “Ortovox” on the shoulder.
This single-minded purpose is much appreciated. Putting on the 185/gsm Rock’N’Wool short sleeve felt like girding for a race and I liked that the fabric didn’t flop around on runs. And the hem drops below the waist and doesn’t ride up when you’re on your bike. The heavier weight wool makes the Rock’N’Wool a better choice for mountain summer or spring and fall, though—I found it to be a bit too insulating once the temps got in the high 70s, low 80s. Like the idea of Ortovox but not the weight of this one? The brand offers short-sleeves in 120, 145, 150, 185, and 230/gsm weights.
Fabric: 100% merino wool. Care: machine wash warm, hang dry
The Merino Midweight base layer crew from REI delivers exactly what you’d expect from the home of the green vests: good value, a simple silhouette that will make most people happy, and no extraneous bells or whistles. Its 18.5-micron merino does the job asked of it without fuss or flash.
Fabric: 100% merino wool. Care: machine wash warm, tumble dry low.
The brand synonymous with wool apparel has twelve tees in its line, ranging from simple solid colors to more lifestyle tees printed with art. Smartwool socks were my gateway to wool back in the early 1990s, and since then I have accumulated its base layers, sweaters, hats, ski socks, and both short- and long-sleeve tees. I have this much Smartwool stuff because the performance is second to none, but I’ve also appreciated that the company is a leader in regenerative merino ranching, animal welfare, and wildlands advocacy.
If you’re looking for one shirt that does it all, I recommend the Merino Sport 150 Tee. As the name suggests, it’s a midweight fabric that takes you from cool to warm days without missing a beat. Sleeves have a bit shorter, modern cut, but the body drapes nicely—in the language of denim, I might call it a slim cut, neither skinny nor relaxed. Smartwool calls it “regular.” Branding is minimal, just a small tag on the hem with Smartwool’s Little Guy, which is easily cut off. Not only is the Merino Sport the most versatile of all these shirts, at $50 it’s the least expensive by 15 bucks.
Fabric: 56% merino wool, 44% polyester. Care: machine wash cold, tumble dry low.
Tracksmith is to running what Rapha is to cycling. It makes exquisitely crafted apparel with flattering cuts that can handle whatever you can throw at it. I have a wool Rapha jersey that I’ve worn on hundreds of rides over the last decade and it shows no signs of wear. The same goes for my pair of the brand’s Longfellow shorts. They cost a seemingly crazy $138, but I’ve had mine for seven years, using them for trail running, hiking, backpacking, swimming, and even mountain biking, and they’re still going strong. I could wear Tracksmith head to toe day in and day out: The two long-sleeve tops I tested had the best fits and nicest tailoring of the bunch; no shirts felt better on my body than Tracksmith’s, nor looked so good. Think boutique, compared to Icebreaker’s independent outdoor retail.
The Brighton Base Layer is designed to be, um, a base layer. Its interior is soft and seamless and feels luxurious against the skin. The merino wool is just 16.5 microns—buttery—and the mesh front and back shed sweat rapidly. Negatives? Just one: It pilled a little under the arms. Not as much as the Icebreaker, but still.
Fabric: 52% merino wool, 28% nylon, 20% polyester. Care: machine wash cold, hang dry.
The Harrier Long Sleeve fits looser and looks more casual than the Brighton, letting you slide from a morning run to the gym to a casual day at work. High merino count (89 percent) makes it exceptionally adaptable to temperature variations, though it does take a little longer to dry. Unlike with the Brighton, we didn’t experience any pilling or negative of any kind.
Fabric: 89% merino wool, 11% nylon. Care: machine wash warm, hang dry.
If Tracksmith is the lean whippet running long miles through the New England countryside, the Voormi River Run Hoodie is closer to your ski town bro chilling in the sun. The cut is loose and relaxed and exceptionally light: The merino/poly blend weighs just 100 grams per square meter and the whole garment only weighs 7 ounces in men’s large. That light weight makes the River Run exceptional in the summer and/or in the desert, where it protects your skin from mean old Mr. Sun without adding heat. It’s roomy enough to wear over a tee, comfy enough to wear against your skin, and super fast-drying. Indeed, the River Run is one of the most versatile tops I’ve ever used, and it should be foundational in every closet. There are men’s and women’s versions, too.
Fabric: 52% merino wool, 48% polyester. Case: machine wash cold, hang dry.
Top photo: Livia Bühler