Copper deficiency is uncommon, but is sometimes found in combination with iron deficiency, especially with iron deficiency anemia. Fatigue, paleness, skin sores, edema, slowed growth, hair loss, anorexia, diarrhea and dermatitis can be symptoms of copper insufficiency. As zinc supplementaion is becoming more popular, the effect of reduced copper absorption seen with increased zinc consumption will probably make deficiencies of copper become more common.

The reduced red blood cell function and shortened red cell life span found with copper deficiency can influence energy levels and cause weakness and labored respiration from decreased oxygen delivery. Low copper levels may also affect collagen formation and thus tissue health and healing. Reduced thyroid function, cardiovascular disease, increased cholesterol, skeletal defects related to bone demineralization and poor nerve conductivity - including irregular heart rhythms - might all result from copper depletion.

Copper deficiency results in several abnormalities of the immune system, such as a reduced cellular immune response, reduced activity of white blood cells and, possibly, reduced thymus hormone production, all of which may contribute to an increased infection rate. Infants fed an all-dairy (cow's milk) diet without copper supplements may develop copper deficiency.