Hello,

I think that for underwear this is not only a problem of materail, it is also a problem of engineering and shape...

Consider prowool (ullfrotte) 200, it's a wool/synthetic terry fleece and it is warm and comfortable because the small loops of wool.
If you look at the shape it's is very well made. Ullfrotte have made first socks and their underwear are made like a sock : a tube with very few flat sewns.
So this is very nice under a shirt and your skin is very happy even after 10 hours under a rucksac.

Very often in US forum you are against polypro underwear because they smell a lot. I think that a lot of people refer to the old army polypropylen underwear.
I have find that with Helly Hansen it's always true but not so much AND you could wash them at 95°C (white, 60°C for black). with this temperature you have no problems with bacterias.

Odlo underwear Brands ( marvellous swiss brands) have polyester underwear that you could wash at 60°C even 90°C for white, not bad for a polyester underwear.

http://www.odlo.com/custom/index2.php3?lan=E


Y use also cotton fishnet from Brynje of Norway. They are not bad for wicking and you could boiled them for cleaning.


So, it is not only a problem of material, kind of material, shape and construction are also very important.

did