Merino wool is a natural, renewable fiber that comes from Merino sheep. The wool is composed of proteins made up of amino acids and natural compounds. Merino sheep are bred predominantly for their wool, and their fleece is sheared at least once a year because it does not stop growing. The wool is fine and soft, and a single Merino wool fiber is ⅓ the diameter of a human hair. Merino wool is highly absorbent, water-resistant, and insulative, making garments made with this type of wool popular for undergarments worn under winter clothing. Depending on how it’s made, merino wool fabric can also be luxuriously soft, countering the scratchiness that is commonly associated with wool. Merino wool is grown year-round by Merino sheep, consuming a simple blend of natural ingredients including sunshine, water, fresh air, and grass. The world’s best Merino wool comes from Australia, which provides 81% of the world’s superfine wool, from woolgrowers who employ sustainable farming practices.