I’m not sure when I got my first “technical” shirt. Probably sometime in college, although, at USAFA we were issued sweet cotton throwback shorts and tees as our mandatory PT gear. No, I probably bought something on my own at some point after realizing that synthetic fibers tended to breathe and dry faster than the old cotton tee. I’m not sure, but my dresser tells you need to know about how I have dressed over the past decade of running. More shorty shorts than you can toss a stick at and scads of technical shirts. Race shirts, specialty shirts, tank tops, tee shirts, long sleeve, crew-zipped, mock turtle – you name it, I probably have it.

What I did not have until this past year was anything that wasn’t born in a lab. What do I mean? Synthetic fibers are just that – man-made. Most tech shirts these days are a blend of some kind polypropylene base and something stretchy. So, your average tech shirt is pretty much plastic.

In the past few years, natural fibers have made a comeback in the sporting apparel industry. For one, and not to be cynical, but companies recognize “green” is a market from which there is money to be made. Natural fibers can be far more green due to the low(er) carbon footprint needed to produce the material (got sheep and some scissors?). Secondly, natural fibers tend to be more durable. Thirdly, companies like Ibex and Icebreaker have figured out how to engineer technical apparel using natural fibers like Merino Wool. In short, this ain’t your granddaddy’s pair of heavy wool pants/lederhosen. The clothing being produced is uber-high quality and looks no different from your favorite pair of running tights or best zip-up running top. Finally, Merino wool has natural antibacterial qualities, which has obvious advantages when it comes to clothes in which one might run.

So, how did I test this shirt? Well, in many ways, when it comes to running, a shirt is a shirt is a shirt, right? Not much different from one to the next in terms of design. It does feature flatlock stitching, which is important to avoid chafing when you wear a pack, but less important for runners. But really, the most important thing to test with a shirt is the material. In this case, I was most interested in both the breathability and odor-resistant properties of the Merino Wool.

Breathability – it’s important to note here that the thickness of the fabric in question is a key aspect, and you should toss out the idea that wool garments are heavy, thick, and cumbersome. Merino wool allows designers to things with wool, like thin out the material without losing durability. The Arc-teryx shirt is pretty thin – think of your favorite tech shirt, how thick that is, and that’s about the thickness you’ve got here. I layered it under a jacket in AK, and wore it solo on runs in CA and it did well in either case. Merino wool fibers wick naturally, as they are hydrophilic at one end and hydrophobic on the the other; when worn next to skin, the shirt literally wants to move perspiration away from your skin, keeping you more dry.

Odor-resistance – I wore this shirt for two weeks straight without washing it, for every workout. Towards the end, I even wore it throughout a day of skydiving just to see if I could overwhelm it with a bunch of weirdness. Nothing, which is more than impressive. Try that with a synthetic shirt and you’ll be divorced/the Smelly Guy at the Gym before you can say “The Future is in Plastics!” So here’s the deal, folks – I pushed several pounds worth of sweat and corresponding funk through this shirt over two weeks without washing, and it didn’t even flinch. When I say it smelled like nothing, I mean nothing. I couldn’t even pick up traces of my own deodorant. Now, I will say that the shirt, when wet with sweat, smells slightly “wooly,” but it beats the alternative, which is…smelling like nasty ass BO. Seriously, is there anything worse than running behind someone with out-of-control funk? Other than actually being that guy?

Bottom Line: Approved. Frankly, it better be, at $90 a pop. Like I’ve said in other reviews, I want what I pay for. This shirt delivers what I want from a base layer/performance tee.