As I age I have discovered some truths that can't be ignored, for me one is that I develop smells after exertion that are not the same as 8-10 years ago - Don't know why or what causes it (other than age) but I can say with authority that it's "there" - I wear IceBreaker merino wool Tshirts and boxers no matter what, YEAH wool USED to make me itch but not as soon as I discovered this stuff (I have Sitka boxers too, JUST as good) I have tried it all as it emerged every season or two, for warmth there are some great new innovations but for the "next to the skin" layer first and foremost give me New Zealand wool stuff and I'll be happy and warm and smiling (and my tent companions too I hope)