REI Co-op  Merino 185 Base Layer Bottoms - Men's

As someone who owns a lot of merino wool and typically runs hot, REI completely nailed this version. It provides the perfect balance of lightweight warmth without overheating. The Fit: Hugs the body exactly how a base layer should. I have a 32-inch waist and the medium fit comfortably snug. Ankle Cuffs: Outstanding design. They aren't overly tight, making them comfy enough for lounging around the house, yet they easily accommodate tucked-in long socks without bunching up. The Look: I picked up not-black color, and it's this cool grey blue. Normally I don't care since it's just underwear, but this color genuinely looks sharp—even my wife commented on how good it looks. Care Tip: If you want to make them even softer, wash them using a delicate wool detergent that contains lanolin. This redesign ticks all the boxes. Highly recommended!

I used these in a pretty wide range of situations. Around the house, I wore them as pajamas. I also wore them underneath a dry suit while whitewater rafting, and on a camping trip I used them as a base layer both around the fire and in my sleeping bag. The first thing I noticed was just how comfortable they are. I also really liked the fit around the waist. You can pull them up above your belly button if you want, but they work just as well sitting below it, and I found both comfortable. I was especially impressed with them rafting. They didn't bunch up underneath my dry suit the way some base layers do, and they kept me nice and warm even after about a three-minute swim in 42-degree water. When I took the dry suit off afterward, the long underwear was damp, which I would expect, but my skin didn't actually feel wet. They were great camping too. At night they were a really comfortable layer inside my sleeping bag, and at around 50 degrees I was warm enough that I could leave a leg outside the bag with these on. Around the fire I wore them under a thin pair of pants and stayed comfortable there too. Even sitting fairly close to the fire, I didn't feel like I was overheating, so the temperature regulation seems really good. Probably my favorite use, though, has been much less adventurous. I sometimes get up early to play games with someone in a different time zone, and sitting at my desk on a cold morning in these is great. They're warm enough that I stay comfortable without feeling like I'm bundled up in heavy clothes. At this point, they've become as much around-the-house clothing for me as an outdoor base layer.

Finally cool enough to wear this base layer for early morning runs. The material is warming but thin enough to not over heat. Perfect for early morning runs, but this will definitely be my skiing base layer when the season starts. Have a camping trip planned for October and will be sleeping in these for the comfort and warmth. REI did a nice job with these.

The material has a good feel and they are very comfortable. They are easy to get on and off, compared to other brands I have which I can barely get over my feet. I’m 6’4”, and they seem a little short. Not terrible, but I personally would like them a little longer. The biggest negative is they feel a little baggy around the mid-section. Again, not terrible, but I would like them a little more form fitting around the middle. Overall a solid light weight base layer that work well for active cold weather activities.

Super comfortable all around. Snug fit but not too tight, long enough to tuck into my socks so that the legs stay in place but not so long that they bunch up anywhere. It’s summer but I wore them camping at night in the 50s and they kept me warm. Lightweight but sturdy material is high quality.