Merino is excellent at regulating body temperature, especially when worn against the skin. The wool provides some warmth, without overheating the wearer. It wicks sweat away from the skin and is slightly moisture repellent, allowing the user to avoid the feeling of wetness.
Wool absorbs water (up to 1/3 its weight), while retaining its warmth when wet, thus helping wearers avoid hypothermia after strenuous workouts (climbs) or weather events.
Like most wools, merino contains lanolin, which has antibacterial properties.
Merino is one of the softest types of wool available, due to finer fibers and smaller scales.
Merino has an excellent warmth-to-weight ratio compared to other wools, in part because the smaller fibers have microscopic cortices of dead air, trapping body heat similar to the way a sleeping bag warms its occupant