REI Co-op  Midweight Long-Sleeve Base Layer Top - Men's

Almost as good as Merino

There is nothing better than Merino wool, but it's expensive and you have to baby it. This doesn't breathe as well as Merino - because nothing can - but it's pretty much just as warm and it infinitely more durable. I was given the item to review, so I did my best to put it through the wringer. I tried to pull it apart at the seams, but they are triple-stitched and did not show any signs of giving up. On top of that, they are consciously placed: the shoulders do not have seams so your pack won't rub blisters, the armpits are gusseted, and the sides are curved to help the shirt lay nicely while you're wearing it. The fabric is thick but smooth, and did not catch on fir trees or branches when I forced my way off-trail through the woods. It is very comfortable next to the skin, is very stretchy, and has great thumb loops. Here are the downsides: it's a thicker material and isn't a next-to-skin fit so it won't layer as nicely. While hiking, it did breath a lot better than my other non-merino tops, but I did sweat a fair amount. Because of its thickness, it will take up more space in your pack (it's roughly the size of a Nalgene. Overall I am happy with this product and would happily buy it since you can get a bunch of them for the same price as Merino, and then don't have to worry about ruining it. (in my photo I am wearing a size L; I am 6'3 230lbs)

Buy some

Took this as part of my gear on the Inca trail. Through multiple weather climates this performed . Breathes well and also keeps you warm . Highly recommended .

Used all winter as a base layer for snowboarding in Colorado. My usual outfit is this, a fleece, and a thin shell. Always kept me nice and toasty. Obviously there are some tradeoffs compared to wool - for example, it offers a similar amount of warmth in winter as my "all season" smartwool baselayer, but would not be suitable for summer use like my smartwool is. So you're paying half the price, but getting half the usability. Just saying. That being said, I'm happy with what I got for the price paid. And often times I do prefer to wear this in winter over my smartwool because its soft and comfortable.

It's not the same as last year's model

This product has definitely been changed this year, and not for the better.The changes, however, have been fairly subtle, and depending on your needs, the changes might not be an issue. Last year's model, of which I own three, has more nap on the surfaces and is a bit thicker. I think they decided to make the shirt cheaper this year to maintain the price point. That's not a good strategy, in my view. That said, it still appears to be a quality shirt. I would say it's leaning more toward a lightweight base layer now, which kind of makes it seem expensive for the warmth provided. If you're thinking about buying one, try to check it out in the store to see if it's what you really want. I mostly wear mine around the house and to walk the dog, so I decided to keep the one I ordered.

Great for Activities and Relaxation

I am very sensitive to cold temperatures, so keeping my body core warm is very important to me. Layering is essential for me, so I am a big fan of base-layer tops and bottoms. I liked the feel of the REI midweight base layer top, so I acquired one and gave it a try. The top is true to its size, so a small size provides the snug feel I prefer. stays close to my skin and provides the first layer. The top has nice design features such as thumb loops on the sleeves and offset shoulder seams. The thumb loops keep the sleeves in place while adding additional layers. The offset shoulder seams help prevent shoulder abrasion when backpacking. This has become my preferred base layer and I wear it frequently. Also, this top is great for casual wear. If you are looking for a good base layer, you cannot go wrong with this top.

Outstanding base layer

After four days of fishing on the Kern River, this layer excelled in several areas. It is a terrific midweight base layer, capable of adapting to warmer temps and wicking away sweat or colder climates keeping body heat where it needs to be. It is extremely durable and feels like a high quality piece. Perfect for layering as the temps drop. It wears very comfortably and resists dirt and stains well also. The added UPF 50 is a nice bonus too. Highly recommend.

surprisingly comfortable, good warmth when layered

Nice fit and finish. Long enough to tuck or not ride up if left loose. Warm by itself is probably around 50-60F depending on sunlight. No wind resistance and not very warm by itself, but good for shoulder weather. Layered with a hoodie or light jacket, is quite warm. I found the material is not very breathable in high humidity (I wore it flying into the tropics) so keep that in mind. No pilling or damage despite my long-haul travel. I'd buy again.

Not thrilled with the changes.

I bought one of these last year and it’s become my go-to favorite for style and comfort, so I grabbed another during the May sales event. It’s changed a bit and I don't care for it as much. I tend to like a bit more height on my collars, and this one appears about 1/8” shorter. That doesn’t sound like much, but it’s noticeable to me. The material also feels a touch thinner than last year’s version, which I preferred. I’ll likely be returning it and looking for a new favorite.

Great For Layering and Casual Wear

I think this shirt fits the description of a midweight base layer perfectly. For me, it's not a shirt I can wear comfortably in temperatures warmer than 15ºC (60ºF). As a single layer, it provides good warmth for cool days and it is an effective midweight layer for colder days. The shirt has a very soft feel to it, is very comfortable to wear, and it looks nice, which means I will be getting one or two more in different colors. I also feel the shirt is constructed well and that it's going to last for some time. The thumb loops are sewn inside the cuff and are a nice addition that keep the sleeves from being pulled up when using as a base layer. During a hike up the steep slopes of Hells Canyon in Idaho, the shirt got pretty wet with sweat, but it did dry relatively quickly. I have to say that I'm very happy with the comfort, fit, and function of this shirt. It will be a go to shirt for cold season trail running, fly fishing, and during the ski season.

Better Than Expected

Fit is pretty close to what I’d expect. The sleeves are a little long for me, but with the thumb holes it make sense, and it would probably fit a 6’ guy pretty well. The thumb holes hold pretty close to the wrist, and didn’t catch too much on other stuff as I was walking around. I also didn’t notice it binding or trying to restrict movement, even when swinging my arms, definitely a plus for me, as I tend to fidget when hiking. Material wise, it’s a little thicker than a normal cotton t-shirt but I do have a heavyweight cotton t-shirt that is about the same weight or a little thicker. I found it very comfortable to wear around, and didn’t notice any seams sliding around while I was wearing it. That material weight means it may not pack down the smallest, but that doesn’t bother me much. Seems to wick pretty well, much better than I expected. Not as good as thinner polyester or merino, but for a midweight I’m impressed. I don’t have any real negatives for this shirt. It does what it says it does. It’s almost certain I’ll take this hiking for those slightly cool weather days, or even for lazy days around the house.