Milk cotton yarn is a specific type of cotton yarn that is made up of a blend of milk fiber and cotton. Milk cotton yarn is considered synthetic or semi-synthetic, and it is made from the casein powder found in milk, mixed together with other substances to give a cotton-like consistency. Milk cotton yarn is known for its softness, smoothness, and suitability for making products that are worn against the skin. Milk cotton yarn has bacteriostatic, breathable, absorbent, thermo-regulating, and hydrating properties. There are a few kinds of milk cotton yarn: the synthetic blend made with acrylonitrile and its natural version made without acrylonitrile, which is far less common. The natural version of milk cotton yarn is made without acrylonitrile and is far less common. Milk cotton yarn is a little tricky to buy, and it is not super available internationally.