The element commonly used to reduce iron oxide is carbon. Carbon in the form of coke or charcoal reacts with iron oxide, reducing it to iron metal. This is a fundamental process in iron extraction and steelmaking. Carbon monoxide, derived from carbon, acts as the reducing agent to convert iron oxide to iron.

Hydrogen is also used as a reducing agent in more environmentally friendly processes, producing water as a byproduct instead of carbon dioxide, but carbon remains the traditional and most common element for reducing iron oxide.