[The physiological function of copper, the etiological role of copper excess and deficiency].

Copper is an essential micronutrient for the human body, taking part in several metabolic processes. It is required for the terminal oxidation, the elimination of free radicals, the proper functioning of iron metabolism, the synthesis of hormones, neurotransmitters and the stabilization of the extracellular matrix. Copper is a two-faced element. Its significance in protein-bounded form is undeniable, but free copper causes severe cell damage mainly through free radical reactions, substituting other essential metals in protein structure, and it has various effects on cell signaling pathways. The amount of copper present in the human body is part of a delicate balance. Both its deficiency and excess can develop severe symptoms and diseases. The nutritional copper balance is rarely broken, because the average daily consumption excessively covers the needs, and the body's copper stores can tolerate the temporary differences. Genetic diseases (Menkes and Wilson disease) helped to understand the copper metabolism and understand the clinical symptoms of deficiency and excessive intake. The role of copper in the development of chronic diseases is receiving increasing attention. Recent studies show its significance in neurodegenerative and cancerous diseases, both in pathogenesis and as a therapeutic target. Orv Hetil. 2020; 161(35): 1488-1496.