When should copper supplements be taken?

When to Take Copper Supplements

Copper supplementation should be initiated when plasma copper levels fall below 8 μmol/L (with or without elevated CRP), or when levels are between 8-12 μmol/L with CRP >20 mg/L, using therapeutic doses of 4-8 mg daily for deficiency treatment—substantially higher than the 1-3 mg daily used for routine supplementation. 1, 2

Clinical Situations Requiring Copper Measurement and Potential Supplementation

Copper levels should be measured in specific high-risk populations before considering supplementation 1:

• Post-bariatric surgery patients (especially gastric bypass or procedures excluding the duodenum) 1, 2
• Patients with unexplained neuropathy of unclear etiology 1
• Major burn patients (whether or not receiving copper supplements) 1
• Continuous renal replacement therapy for more than 2 weeks 1
• Home enteral nutrition via jejunostomy tubes 1
• Long-term parenteral nutrition (monitor every 6-12 months) 1

Diagnostic Thresholds for Copper Supplementation

Always measure plasma copper simultaneously with CRP to distinguish true deficiency from inflammatory changes, as ceruloplasmin (the major copper transport protein) is an acute phase reactant that falsely elevates copper during inflammation 1, 2:

• Plasma copper <8 μmol/L: Severe deficiency requiring immediate repletion measures regardless of CRP 1, 2
• Plasma copper <12 μmol/L with CRP >20 mg/L: Likely deficiency where copper administration should be considered 1

Therapeutic Dosing for Copper Deficiency

For established copper deficiency (especially with myelopathy): Use 4-8 mg copper daily, which is substantially higher than prophylactic doses 2. This therapeutic dose is necessary for treating deficiency and should not be confused with routine supplementation doses of 1-3 mg daily used for prevention 1, 2.

Route of administration should be determined by severity 2:

• Oral copper is preferred for chronic conditions and less severe deficiency 1
• Intravenous copper should be considered for rapid correction in severe myelopathy with neurological symptoms or when oral therapy fails 2

Routine Supplementation in Enteral and Parenteral Nutrition

Enteral nutrition should provide 1-3 mg copper per day with 1500 kcal for routine supplementation 1

Parenteral nutrition dosing 1:

• Preterm infants: 40 μg/kg/day
• Term infants and children: 20 μg/kg/day (maximum 0.5 mg/day for routine supplementation)
• Patients with high gastrointestinal fluid losses: Increase by 10-15 μg/kg 1

Critical Zinc-Copper Interaction

Always check both zinc and copper levels simultaneously before initiating copper supplementation, as excessive zinc is a common cause of copper deficiency 3, 2. The interaction is bidirectional:

• High zinc blocks copper absorption by inducing metallothionein in enterocytes, which preferentially binds copper 3
• When supplementing both minerals therapeutically, maintain a zinc-to-copper ratio of 8:1 to 15:1 3, 2
• If treating hypercupremia with zinc, monitor copper levels every 3 months, as excessive zinc can cause severe copper deficiency requiring IV copper administration 3

Common Pitfalls to Avoid

• Do not use standard supplementation doses (1-3 mg daily) to treat established deficiency—these are prophylactic doses only and insufficient for treatment 1, 2
• Do not supplement copper without checking zinc levels first, as high zinc is a frequent cause of copper deficiency 3, 2
• Do not assume normal copper levels if CRP is elevated, as inflammation falsely raises copper concentrations 1, 2
• Do not delay treatment in severe cases waiting for specialist referral—initiate copper replacement immediately while arranging follow-up 2
• Do not ignore neurological symptoms, as copper deficiency myelopathy may be irreversible if treatment is delayed 2

Special Considerations in Cholestasis

While copper is primarily excreted through bile, recent data suggests that removing copper from parenteral nutrition in cholestatic patients may cause deficiency 1. Nevertheless, copper status should be monitored closely in patients with cholestasis, and plasma copper and ceruloplasmin levels should be checked regularly 1.