Arc'teryx  Ionia Merino Wool Long-Sleeve Base Layer Top - Men's

Don’t waste your money. After a couple months of normal wear and following the tag instructions for care the shirt has become stretched out to the point where the sleeves and hem and too long and the shirt it self is see thru. This shirt is the biggest waste of money I’ve made on a base layer, I do not expect this lack of quality from ArcTeryx. Honestly done with ArcTeryx after this product. Their quality has gone down hill over the past few years.

Recently picked up the purple one in both the shirt and the hoody - was a bit worried about the quality and durability based on a couple of reviews - but as it turns out - the latest versions of this top are as GREAT as previous years. Super durable - fabric has a beautiful feel. I do find that these fit better in a L over a M (I have worn Med in Arcteryx for everything except Ionia and the Thorium ... which I select a Large - I'm 6'1" and 185 lbs). Would def recommend the Ionia if you are looking for something comfy and casual. Love how this shirt feels and breathes.

Excellent base layer for active effort. I use this for outdoor and indoor climbing. It's thin enough that i don't overheat, and it's long enough that it reduces abrasions and keeps the bugs off. I always machine wash gentle and hang dry. Do this and it will last multiple seasons of hard wear in rotation. The longer cut means i can reach high without the shirt untucking from my harness, which i like. I am a midweight 5'9" and wear an XS—it's snug to my liking.

I've had this T-shirt for three weeks. I am very satisfied, so I will buy more. I would like to ask you to expand your collection with a model with a button-down collar, a turtleneck, long-sleeved version and short-sleeved version, preferably in black :)

Received this shirt as a Christmas gift. Wore it a handful of times and upon wash (following the care instructions) the shirt shrunk and warped to what feels like a whole size down. I hope it can be saved and restored with another wash and hang dry.

The shirt fits well, looks good, and is very soft. With that being said, it is the most fragile shirt I have ever owned. Just wearing around the house and it has already developed a thread pull that looks terrible. It is as fragile as nylons.

I have been using this crew neck almost exclusively as a base layer under a thin wind resistant running jacket, when running in colder conditions. I find it perfect for such use. It keeps me warm, even if sweating a lot.

I wear this for running as a stand alone layer and as a base layer. I'm 5'9" 150lbs and went with a medium for a looser fit. No odor issues after several uses. I would love to see a lighter white/beige/natural color.

Get the Rho long sleeve instead of this. This one is way too long for me in XL at 6'3". The material is thinner too. Not worth it.

I use this as an all round base layer. It is light, soft and super comfortable to wear. Great for those multi day trips.