Icebreakers come in different weights. I wear them year round, from summer hiking / backpacking to winter mountaineering and skiing. I like how they keep me warm and don't stink like synthetics tend to on multi-day backcountry trips. I wear their panties, too. That said, the heavier weights (260 & 320) do seem to be a bit "scratchier" and I solve that problem by wearing their camisoles, which are ultra fine, under the 260 or 320.