Smartwool or capilene what say you? I heard capilene gets kinda stretched out after a few uses/washes.

I have one wool base layer and a few synthetic base layers. Overall, I prefer the synthetic, aside from the stink factor. The wool can go for so long without getting rank. The wool doesn't seem to move perspiration away as well as the synthetic. It seems to soak up more moisture although it doesn't "feel" wet and cold normally, unless you were to take it off and put it back on. Wool seems to be a bit warmer, so I wear it during the winter and stick to my synthetic in the summer or whenever I will be sweating (which is usually any aerobic activity for me).

I'm pretty much exclusively UA these days.. but I don't ever have need for insulating base layers. The UA does not stretch out, keeps the chill off the skin, and I personally don't have a problem with odor

Mis dos centavos.

My preference is for merino wool products. They are more comfortable, better for insulation, breath well, and have no odor issues. The issue with odor is the biggest deal killer for me... if I can smell myself that easily, I know others are smelling much more!

I mix it up generally. Trusty Patagonia r1 hoody on top or silkweight capilene and smartwool/icebreaker/Patagonia wool bottoms.

And my wish list for underwear. I wish the umm crotch region on leg underwear used a lighter fabric than the rest of thermal. Give my man bits a bit of a breather I see lighter fabrics used on some garments on the underarms...why not the crotch area.

I have under armor cold weather long underwear, how do they compare to capaline thickness? 2? 3?

capilene sorry

I'm with Mountainsandsound. I love my merino wool base layers, but they take too long to dry out for me...I sweat quite a bit. I've been using Capilene as my go-to since the 80's and just do an alpine washing to keep the stank down. Like most gear/clothing, there are trade-offs.