Copper
Cu
Essential trace mineral for iron metabolism, nerves, and connective tissue.
Strong evidence
🧂Mineral
Evidence tier
Strong
Research weight
Citations
8 verified / 8
Classification
Mineral
❝
What the evidence says. Multiple high-quality RCTs / meta-analyses with consistent effects.
What is Copper?
Copper (Cu) is a mineral used for corrects copper deficiency anemia and neutropenia (often from zinc excess or bariatric surgery) — restores blood counts when repleted. NutriDex grades the human evidence as Strong. Copper is an essential trace mineral and cofactor for enzymes governing iron metabolism (ceruloplasmin), energy production (cytochrome c oxidase), connective-tissue cross-linking (lysyl oxidase), antioxidant defense (Cu/Zn superoxide dismutase), and neurotransmitter synthesis. Frank deficiency, most often from excess zinc, bariatric surgery, or malabsorption, causes anemia, neutropenia, and a reversible myeloneuropathy; the genetic disorder Menkes disease is fatal without copper injections. Outright dietary deficiency is rare because requirements are low and copper is widespread in food, and there is no good evidence that supplementing copper benefits well-nourished people. On the contrary, observational data link higher dietary and serum copper to increased cardiovascular events and mortality, so routine supplementation is not advised outside documented deficiency.
Purported Benefits
✓Corrects copper deficiency anemia and neutropenia (often from zinc excess or bariatric surgery) — restores blood counts when repleted
✓Reverses acquired copper-deficiency myeloneuropathy, an under-recognized treatable cause of gait/sensory deficits
✓Required for iron mobilization via ceruloplasmin; deficiency causes a microcytic/normocytic anemia unresponsive to iron alone
✓Cofactor for connective-tissue cross-linking (lysyl oxidase) and antioxidant SOD — deficiency impairs bone/vascular integrity
✓Component of AREDS2 eye formula (2 mg cupric oxide) added to offset zinc-induced copper depletion, not for independent benefit
✓No proven benefit (and possible cardiovascular harm) from supplementing copper-replete adults
Evidence by outcome
The same supplement can be well-proven for one use and unproven for another — here is the human evidence graded outcome by outcome.
| Outcome | Evidence | Effect | Studies |
|---|---|---|---|
| Corrects copper-deficiency anemia and neutropeniaRepletion reliably restores blood counts in deficiency (zinc excess, bariatric surgery); not for replete people. | Strong | ↑ benefit · large | 2 |
| Reverses acquired copper-deficiency myeloneuropathyRepletion treats this under-recognized gait/sensory disorder; based on case series, an established but treatable deficiency. | Moderate | ↑ benefit · large | 1 |
| Cardiovascular benefit from supplementing replete adultsRCT of up to ~7 mg/day raised some enzyme activities but gave no meaningful cardiovascular improvement. | Moderate | — no effect · negligible | 1 |
| Cardiovascular events/mortality with higher copper statusMeta-analysis and large cohort link highest serum/dietary copper to higher stroke, MI and mortality; observational. | Moderate | ⚠ risk · moderate | 2 |
| Bone mineral density / fracture benefit2025 systematic review found heterogeneous, inconsistent results with no clear bone benefit from higher copper. | Preliminary | — no effect | 1 |
Dosing & Compounds
Typical Dose
Adult RDA 900 mcg/day (0.9 mg); pregnancy 1,000 mcg, lactation 1,300 mcg. Typical supplement/multivitamin dose 0.5–2 mg/day. Tolerable Upper Intake Level (UL): 10,000 mcg/day (10 mg) for adults per US IOM, set on liver protection; EFSA's 2023 re-evaluation concluded no copper retention occurs up to ~5 mg/day.
Active Compounds
Safety & Cautions
UL is 10 mg/day (US IOM); acute overdose causes nausea, vomiting, abdominal pain, and can progress to liver and kidney damage. Wilson disease (ATP7B mutation) causes pathologic copper accumulation with liver and neurologic injury — these patients must restrict copper and use chelators/zinc. Key interactions: high-dose zinc (>40 mg/day, including denture creams and cold lozenges) induces copper deficiency via metallothionein; conversely copper supplements offset zinc's copper-lowering effect (basis for the 2 mg copper in AREDS2). Excess vitamin C and bariatric surgery impair copper status. Observational studies link higher serum/dietary copper to greater cardiovascular and all-cause mortality, so do not supplement without documented deficiency. Educational only — always check with your doctor or pharmacist before combining Copper with any medicine.
Key Studies
Meta-analysis
Munoz-Bravo 2023 (meta-analysis, Front Cardiovasc Med)
✓ Full text
Meta-analysis of 16 studies (41,322 participants) found highest vs lowest serum copper associated with higher stroke (pOR 1.49, 95% CI 1.22-1.82), myocardial infarction (pOR 1.31, 95% CI 1.17-1.46), and cardiovascular mortality (pOR 1.60, 95% CI 1.39-1.86).
Systematic review
Chen 2025 (bone health meta-analysis, Calcif Tissue Int)
✓ Source
Systematic review/meta-analysis of observational studies of dietary copper intake and bone mineral density/fracture found heterogeneous, inconsistent results, with no clear evidence that higher copper intake improves bone outcomes.
RCT
DiSilvestro 2012 (RCT, Eur J Clin Nutr)
✓ PubMed
Randomized trial of copper supplementation (up to ~7 mg/day) in adults found increases in some copper enzyme activities but no meaningful improvement in cardiovascular-related parameters, providing no support for routine copper supplementation.
Authoritative review
Linus Pauling Institute (copper micronutrient review)
✓ Source
Authoritative review confirms copper is essential for ceruloplasmin/iron metabolism, lysyl oxidase, cytochrome c oxidase and SOD, that acquired deficiency (e.g., from excess zinc) causes anemia, neutropenia and myeloneuropathy, and that supplementation is unwarranted in replete adults.
Prospective cohort
Li 2023 (PURE-China cohort, BMC Public Health)
✓ Full text
In 45,101 Chinese adults over a median 11.9 years, the highest vs lowest quartile of dietary copper intake was associated with higher all-cause mortality (HR 1.22, 95% CI 1.08-1.39) and CVD incidence (HR 1.25, 95% CI 1.06-1.47).
Authoritative body
EFSA 2023 re-evaluation
✓ Source
EFSA's re-evaluation of copper guidance values concluded no copper retention (accumulation) is expected at intakes up to ~5 mg/day and lowered the acceptable daily intake to 0.07 mg/kg bw.
Authoritative body
NIH ODS Copper Fact Sheet 2022
✓ Source
Adult RDA is 900 mcg/day and the Tolerable Upper Intake Level is 10,000 mcg/day, based on protection from liver damage; deficiency is rare in healthy people but causes anemia, neutropenia, and neurologic problems.
Authoritative body
IOM Dietary Reference Intakes (copper)
✓ Full text
The Institute of Medicine set the adult copper UL at 10 mg/day with hepatic effects as the critical endpoint, and notes copper deficiency from diet alone is uncommon in the general population.