Human Lactoferrin (LF) also known as Lactotransferrin (LTF) is a multifunctional protein of the transferrin family. It is an iron-binding glycoprotein that facilitates the production of hydroxyl radicals and chelates iron, preventing its accessibility to microorganisms and thus inhibiting growth. It is found in secondary granules of polymorphonuclear neutrophils, lacking terminal fucose residues in the glycan chains that are required for binding to macrophages.

Lactoferrin plays an important role in iron transport and utilization in humans. It is capable of binding two ferric ions with high affinity. Although lactoferrin binds iron tightly, the binding is reversible so that the metal is available upon demand to cells.