Copper is an essential trace mineral required for many enzymatic processes in the body. It is a cofactor for enzymes involved in energy production, iron metabolism (ferroxidase activity via caeruloplasmin), connective tissue synthesis (lysyl oxidase), antioxidant defence (copper-zinc superoxide dismutase), and neurotransmitter synthesis. About 90% of copper in the blood circulates bound to caeruloplasmin.

The body tightly regulates copper absorption and excretion through the liver, which is the central organ of copper homeostasis. The most clinically important conditions of copper dysregulation are Wilson's disease (genetic copper accumulation causing liver and neurological disease) and copper deficiency (causing anaemia, neutropenia, and neurological dysfunction). Copper is obtained from shellfish, organ meats, nuts, seeds, and whole grains.