Copper

Supplementation is only appropriate for documented deficiency. Most adults get adequate copper from food. Excess copper is neurotoxic.

A rough internal score reflecting quantity, quality, and consistency of human evidence. Not a clinical recommendation.

Essential for ceruloplasmin, cytochrome c oxidase, and superoxide dismutase. Deficiency causes anemia and neutropenia. Excess is linked to liver damage and possibly Alzheimer's progression. Zinc supplementation without copper can cause copper deficiency.

• Essential for iron metabolism and red blood cell formation
• Required for connective tissue cross-linking
• Necessary to balance zinc supplementation

RDA: 900 mcg/day. 1–2 mg/day when supplementing to offset zinc-induced depletion. UL: 10 mg/day.

• Nausea at high doses
• Liver toxicity with chronic excess
• Metallic taste

Copper excess is toxic (Wilson's disease is the extreme). People supplementing zinc (>25 mg/day) may need copper to prevent deficiency.

A narrow therapeutic window—both deficiency and excess are harmful. Routine supplementation without monitoring is not recommended.

• Immunity30