Vitamins & Supplements · Mineral
Copper
Cu (cuprum) · also called Cu, cobre
Copper is an essential trace mineral that works with iron to make red blood cells and helps nerves, blood vessels, the immune system and bones. Most people get enough from nuts, seeds, shellfish, organ meats and whole grains. The best evidence is for correcting a true deficiency; there is no good evidence that extra copper helps people who are not low. The main cautions are too much zinc, which causes copper deficiency, Wilson disease, and long-term high doses, which can harm the liver and kidneys.
General information, not medical advice. Last substantive update · Not medically reviewed. A named clinician has not signed off on this page. How this page is made
About Copper
Copper is an essential trace mineral that the body cannot make. It helps form red blood cells and keeps nerves, blood vessels, the immune system and bones working. It is a nutrient, not a proven remedy: the benefit is in fixing a true shortfall, and too much is harmful.
What it is
Copper is an essential trace element found in all body tissues. MedlinePlus says the body cannot make its own copper, so it has to come from food. It works with iron to form red blood cells and haemoglobin, helps release iron, and helps keep blood vessels, nerves, the immune system and bones healthy.
At the cell level, copper is taken up by gut cells through a transporter called Ctr1 and sent into the blood by a pump called ATP7A. Copper-dependent enzymes include superoxide dismutase 1 and ceruloplasmin, the main copper-carrying protein in blood.
Food sources
MedlinePlus names oysters and other shellfish, whole grains, beans, nuts, potatoes and organ meats such as kidneys and liver. Dark leafy greens, dried fruit such as prunes, cocoa, black pepper and yeast also contribute. The NHS lists nuts, shellfish and offal.
USDA values per 100 g: sesame seeds 4.082 mg, unsweetened cocoa powder 3.788 mg, raw cashews 2.195 mg, dried sunflower seed kernels 1.8 mg, English walnuts 1.586 mg, dried pumpkin seed kernels 1.343 mg, boiled chickpeas 0.352 mg and boiled lentils 0.251 mg. Typical portions: 1 oz of cashews has about 0.62 mg, 1 tablespoon of sesame seeds about 0.37 mg, 1 oz of pumpkin seeds about 0.38 mg, 1 oz of walnuts about 0.45 mg, 1 tablespoon of cocoa powder about 0.20 mg, a cup of boiled lentils about 0.50 mg and a cup of boiled chickpeas about 0.58 mg (calculated from the USDA per-100 g values and portion weights). Shellfish and organ meat amounts were not read.
Too little copper
MedlinePlus says people normally get enough copper from food, and that a lack may lead to anemia and osteoporosis. Deficiency is more often acquired than inherited. Causes named in reviews include gastric bypass surgery, which reduces absorption, prolonged continuous kidney replacement therapy in hospital, and too much zinc.
Deficiency mainly affects the blood (anemia, low white cells) and the nerves (myeloneuropathy). It is diagnosed with serum copper, ceruloplasmin and 24-hour urine copper. A 2018 review says blood effects are fully reversible over 4 to 12 weeks of copper replacement, but nerve effects only partly. This is clinician-led care, not something to self-treat.
Menkes disease is a very rare inherited disorder of copper handling in male infants, present before birth. It is not caused by diet.
What the research shows
In people who are not deficient, copper supplements have not shown clear benefit. A 2021 meta-analysis of 5 trials (176 people) found no significant change in total, LDL or HDL cholesterol. In a 2012 trial, copper raised copper enzyme activity over 8 weeks but did not consistently improve heart-health blood markers.
Blood copper is a different matter: in 17 cohort studies (47,813 people), higher blood copper went with more stroke, coronary death, cardiovascular death and death from any cause. Illness raises blood copper, so this may be a marker, not a cause.
A 2025 meta-analysis found higher dietary copper went with slightly higher lumbar spine bone density, an observational result. A 2023 cohort found faster thinking decline in older adults who ate the least copper, and a 2021 meta-analysis found higher blood copper in people with Alzheimer's. No trial of copper for bone, thinking or Alzheimer's was found.
Food versus supplements
The food facts here are USDA nutrient amounts and food-record studies. The supplement results come from one randomised trial (copper glycinate) and a pooled analysis of 5 trials. Copper replacement for deficiency uses copper gluconate, sulfate or chloride, by mouth or by vein, under clinician direction. No source read compared absorption from foods and supplement forms, so the forms are not ranked here. The NIH Office of Dietary Supplements fact sheet was blocked and was not read.
At a glance
Traditional uses history, not proof
- Needed in small amounts in every diet as an essential nutrient
- Long use as a nutrient is not proof that extra copper treats any condition
Studied for research
- Food sources, high certainty for the nutrient content
- Copper deficiency anemia, moderate certainty (reviews, no randomised trial)
- Nerve damage from deficiency, low certainty (partly reversible)
- Deficiency after gastric bypass and after too much zinc, low certainty (reviews and case reports)
- Cholesterol and heart-health markers, low certainty of no clear effect
- Heart disease and death, moderate certainty that high blood copper is a warning sign (observational)
- Bone density, low certainty (observational)
- Thinking and Alzheimer's disease, very low certainty
Main compounds
- Copper gluconate
- Copper sulfate and chloride
- Copper glycinate
- Copper-histidine (a prescription injection)
Common forms
- Copper from food (nuts, seeds, shellfish, organ meats, whole grains, cocoa)
- Copper supplements and multivitamins with copper, in several forms
- Copper replacement given by vein for deficiency
- Copper-histidine injection for Menkes disease
Research links: 2018 review: copper deficiency anemia · 2026 review: zinc-induced blood toxicity and low copper (37 cases) · 2021 meta-analysis: copper supplements and blood lipids (5 trials) · 2024 meta-analysis: blood copper and cardiovascular risk · Research Library · Genes & Biomarkers Library
What it is and its history
- Accepted scientific name
- Copper
- Naming authority
- Not a plant or animal: a chemical element and essential trace mineral (symbol Cu)
- Common names
- Copper (English); Cu (symbol); Cuprum (Latin); Cobre (Spanish)
- Family or group
- Essential trace mineral. MedlinePlus: 'an essential trace element present in all body tissues' that the body cannot make.
- Classification
- Trace mineral (essential)
- Look-alikes and adulterants
- Name: Zinc; Note: A neighbouring trace mineral that competes with copper for absorption.; Name: Iron; Note: Works with copper to make haemoglobin.; Name: Manganese; Note: Another trace mineral that is often listed with copper.
What is inside, and how it may work
What it contains and how those compounds act in cells and animals. Laboratory and animal mechanisms are not proven effects in people.
Main compounds
| Compound | Family | Where it is concentrated | Activity studied | Level of evidence |
|---|---|---|---|---|
| Copper gluconate | supplement form (salt) | Not stated in the sources read | Named in the 2018 review as a form used to replace copper in deficiency anemia, orally or by vein. 8 | Human data |
| Copper sulfate and copper chloride | supplement form (salt) | Not stated in the sources read | Also named in the 2018 review for replacement in deficiency anemia. 8 | Human data |
| Copper glycinate | supplement form (amino acid chelate) | Not stated in the sources read | The form used in the 2012 randomised trial; it raised copper enzyme activity but did not consistently change heart markers. 2 | Human data |
| Copper-histidine | prescription injection | Not applicable | Injected treatment for Menkes disease when started in the newborn period. 10 | Human data |
| Cupric oxide and other forms in multivitamins | supplement form | Not stated | Listed in the existing nutrient summary only. No source read compared forms for absorption or effect. 14 | Summary only |
Mechanisms, receptors and pathways
| Target or pathway | Gene or receptor | What was found | Level |
|---|---|---|---|
| Copper uptake and export in the gut | Ctr1 (uptake); ATP7A (export into blood) | The 2018 review says dietary copper enters intestinal cells through the Ctr1 transporter and leaves them via the Cu-ATPase ATP7A. Zinc absorption is slightly different but may use Ctr1. 8 | Human data |
| Iron use and red blood cell formation | Not specified in the sources read | Copper works with iron to form red blood cells and helps release iron to form haemoglobin (MedlinePlus, NHS). 14 16 8 | Human data |
| Copper-dependent enzymes | Superoxide dismutase 1 (SOD1), ceruloplasmin | In a randomised trial, copper raised red-cell SOD1 and plasma ceruloplasmin activity. The 2018 review lists roles in iron oxidation, cellular respiration, antioxidant defence, peptide amidation, neurotransmission and connective tissue. 2 8 | Human data |
| Copper removal by the liver | ATP7B | Wilson disease is a disorder of copper metabolism; the Alzheimer's meta-analysis also examined ATP7B gene variants in a replication study (an association, not a mechanism). 15 4 9 | Human data |
Absorption, metabolism and elimination
- Absorption
- Dietary copper enters gut cells through the Ctr1 transporter (2018 review). High zinc reduces copper absorption (NHS). Absorption falls after gastric bypass surgery (2019 review).
- Distribution
- Most blood copper is carried by ceruloplasmin (the abstracts name it as a diagnostic marker).
- Metabolism
- Not found.
- Elimination
- In healthy people the liver releases extra copper into bile (MedlinePlus, Wilson disease). Wilson disease prevents this.
- Bioavailability
- Not established in the sources read; absorption of copper from different foods and supplement forms was not compared.
Isolated compounds versus whole extracts
The food results here are nutrient content from USDA tables, and the dietary-intake studies (bone, thinking) use food records. The supplement results are the 2012 randomised trial and the 2021 lipid meta-analysis. Blood copper studies measure blood, not intake. Food copper comes with other nutrients and may be absorbed differently from pills, but this was not compared in the sources read.
Nutritional composition
Copper content per 100 g from USDA FoodData Central (SR Legacy, April 2018 release), read from the project's saved copy on 2026-10-26: sesame seeds 4.082 mg, unsweetened cocoa powder 3.788 mg, raw cashews 2.195 mg, dried sunflower seed kernels 1.8 mg, English walnuts 1.586 mg, dried pumpkin seed kernels 1.343 mg, boiled chickpeas 0.352 mg, boiled lentils 0.251 mg. Shellfish and organ meats are named as sources by MedlinePlus and the NHS, but their USDA values were not read.
1 high certainty3 moderate certainty5 low certainty1 very low certainty
What was looked at
The 10 benefits and uses checked for Copper, each with how strong the evidence is. Tap one to open it.
- Food sources of copper (nutrient content)High certainty
- Correcting copper deficiency: anemia and low blood cellsModerate certainty
- Nerve and spinal cord problems from deficiencyLow certainty
- Copper deficiency after gastric bypass surgeryLow certainty
- Copper deficiency caused by too much zincLow certainty
- Cholesterol and heart-health blood markers (in people not shown to be deficient)Low certainty
- Heart disease and death: high blood copper (a warning sign, not a benefit)Moderate certainty
- Bone densityLow certainty
- Thinking, memory and Alzheimer's diseaseVery low certainty
- Menkes disease (a rare inherited copper disorder)Moderate certainty
Lab markers tracked in the studies
Serum copperCeruloplasminBlood counts (anemia, white cells)Total, LDL and HDL cholesterolOxidized LDLC-reactive protein and homocysteineCopper enzyme activity (superoxide dismutase 1, ceruloplasmin)Bone mineral density (spine and hip)
What is Copper good for?
The main studied uses and how strong the human evidence is for each. Most of the real benefit is in correcting a true deficiency. In people with normal copper, trials found no clear benefit.
Benefits, one by one
Each card is a research question, not a promise. Tap a goal to filter. Open a card to see the studies, doses and limits.
Food sources of copper (nutrient content)
High certaintyCopper is found in shellfish, organ meats, nuts, seeds, whole grains, beans, potatoes and cocoa. USDA tables give the amounts for common foods.
10 studiesFood. Amounts vary with variety, soil and how food is processed or co…
Studies, doses and limits
What the trials found
No trial was read testing whether eating these foods changes copper status. This is a nutrient-content fact, not a trial result.
Results
Per USDA, 1 oz (28.35 g) of raw cashews has about 0.62 mg of copper, 1 tablespoon of whole sesame seeds about 0.37 mg, 1 oz of dried pumpkin seed kernels about 0.38 mg, 1 oz of English walnuts about 0.45 mg, 1 tablespoon of unsweetened cocoa powder about 0.20 mg, a cup of boiled lentils about 0.50 mg and a cup of boiled chickpeas about 0.58 mg (portion amounts calculated from USDA per-100 g values). MedlinePlus and the NHS also name shellfish and organ meats such as liver; amounts for those were not read.
Effect sizes as reported
USDA copper per 100 g: sesame seeds 4.082 mg, unsweetened cocoa powder 3.788 mg, raw cashews 2.195 mg, dried sunflower kernels 1.8 mg, English walnuts 1.586 mg, dried pumpkin seed kernels 1.343 mg, boiled chickpeas 0.352 mg, boiled lentils 0.251 mg.
Why this rating
High that the foods contain these amounts (USDA data). Not a test of health effects.
Form and dose studied
Food. Amounts vary with variety, soil and how food is processed or cooked.
Who was studied
General diet.
Limits
Food composition, not trials. Shellfish, organ meats, potatoes and prunes were named by MedlinePlus but their USDA values were not read. Absorption from food was not covered by the sources read.
Why researchers looked
People look to food first for minerals. Knowing which foods hold copper helps explain why deficiency from diet alone is uncommon.
Traditional use
Copper is an essential mineral. Its roles are established nutrition science, not traditional use.
Proposed mechanism Nutrient database
These are nutrient amounts in foods, taken from USDA tables.
A proposed mechanism does not show that the effect happens in people.
Wilson disease: MedlinePlus says people with it should avoid shellfish and liver; see Safety.
Correcting copper deficiency: anemia and low blood cells
Moderate certaintyWhen someone is truly low in copper, giving copper brings the blood counts back. The blood effects were fully reversible over about 4 to 12 weeks in a review.
4 studiesCopper gluconate, copper sulfate or copper chloride, oral or intraven…
Studies, doses and limits
What the trials found
Two reviews describe copper replacement (oral or intravenous copper gluconate, sulfate or chloride) correcting the blood problems of deficiency. No randomised trial was read; the evidence is case series and clinical reviews.
Results
In a 2018 review, the blood effects of deficiency were fully reversible with copper over 4 to 12 weeks. A 2019 review says some severe cases need intravenous repletion. This applies to people who are deficient, not to people with normal copper.
Effect sizes as reported
Blood effects 'fully reversible' over 4 to 12 weeks (2018 review). No effect sizes in the abstracts.
Why this rating
Moderate: the reviews agree and the finding is long-established clinical practice, but it rests on cases and narrative reviews, not randomised trials.
Form and dose studied
Copper gluconate, copper sulfate or copper chloride, oral or intravenous, as named in the 2018 review. Doses are not stated here.
Who was studied
Adults and others with confirmed copper deficiency.
Limits
Narrative reviews, no pooled data. It tells us nothing about people whose copper is already normal. Diagnosis and treatment need a clinician.
Why researchers looked
Copper helps the body use iron and make haemoglobin and white blood cells, so low copper can look like iron-resistant anemia or low white cells.
Traditional use
Copper is an essential mineral. Its roles are established nutrition science, not traditional use.
Proposed mechanism Review of lab and human evidence
Copper works with iron: it helps release iron so it can be used to make haemoglobin. Copper is taken up by cells through the Ctr1 transporter and moved out by the ATP7A pump.
A proposed mechanism does not show that the effect happens in people.
Too much copper is harmful; see Safety. Do not self-treat suspected anemia.
Nerve and spinal cord problems from deficiency
Low certaintyLow copper can damage nerves and the spinal cord (called myeloneuropathy). Copper replacement helps only partly: nerve damage was only partially reversible.
3 studiesCopper replacement as described in the reviews; amounts not stated he…
Studies, doses and limits
What the trials found
Reviews say deficiency affects the nervous system and that nerve effects improve only partly with copper, unlike the blood effects.
Results
The 2018 review: neurological manifestations are only partially reversible with copper. The 2019 review: hematologic and neurologic complications can go untreated because copper deficiency was not considered. Zinc-related cases: nerve problems improved more slowly and were sometimes incomplete.
Effect sizes as reported
No numbers in the abstracts.
Why this rating
Low: consistent descriptions, but from narrative reviews and case reports; no trial or recovery rates were read.
Form and dose studied
Copper replacement as described in the reviews; amounts not stated here.
Who was studied
People with confirmed copper deficiency.
Limits
Case-based evidence. Early diagnosis is stressed, but no study of how early treatment changes outcomes was read.
Why researchers looked
Copper-deficient patients can present with trouble walking, numbness and similar nerve problems that are easy to mistake for other conditions.
Traditional use
Copper is an essential mineral. Its roles are established nutrition science, not traditional use.
Proposed mechanism Review of lab and human evidence
Not established in the sources read. The 2018 review lists neurotransmitter and antioxidant defence roles for copper.
A proposed mechanism does not show that the effect happens in people.
Urgent signs are listed on the Safety tab.
Copper deficiency after gastric bypass surgery
Low certaintyGastric bypass can leave people low in copper. A review found that adequately supplemented patients rarely become deficient, and deficiency can be treated when found.
2 studiesCopper supplements after surgery are described by the review; amounts…
Studies, doses and limits
What the trials found
A 2016 systematic review concluded that copper deficiency in adequately supplemented patients is rare and can be treated if a blood or nerve disorder is diagnosed. It argued routine testing may not be justified for adequately supplemented people without symptoms, with testing for high-risk groups.
Results
The 2016 review notes that a large number of people having bariatric surgery are already deficient in copper, and that British guidance recommends annual copper testing after gastric bypass.
Effect sizes as reported
No counts in the abstract.
Why this rating
Low: a systematic review, but the abstract gives no numbers and the underlying studies are observational.
Form and dose studied
Copper supplements after surgery are described by the review; amounts not stated here.
Who was studied
People after Roux-en-Y gastric bypass.
Limits
Review conclusions differ on routine testing. Follow the bariatric team's advice.
Why researchers looked
Absorption of minerals falls after bypass surgery, and severe copper deficiency after bypass has become frequent.
Traditional use
Copper is an essential mineral. Its roles are established nutrition science, not traditional use.
Proposed mechanism Review of lab and human evidence
Reduced absorption after the surgery (as described by the 2019 review).
A proposed mechanism does not show that the effect happens in people.
Not an advice to start copper; your surgical team decides.
Copper deficiency caused by too much zinc
Low certaintyTaking high amounts of zinc blocks copper absorption. A review of 37 case reports found low copper in every patient and recovery of blood counts in most once zinc was stopped and copper given.
3 studiesZinc exposure in the cases ranged from about 50 mg to over 1500 mg of…
Studies, doses and limits
What the trials found
A 2026 systematic review of 34 publications (37 cases, 1972 to 2025) found anemia in nearly all, low serum copper in all, and recovery in most after zinc exposure stopped and copper was given. Nerve problems improved more slowly.
Results
The NHS says high zinc doses reduce the copper the body can absorb, which can lead to anaemia and weakening of the bones.
Effect sizes as reported
Serum copper reduced in all 37 patients; blood recovery in the majority.
Why this rating
Low: consistent, but only case reports. The authors call it uncommon but under-recognised.
Form and dose studied
Zinc exposure in the cases ranged from about 50 mg to over 1500 mg of elemental zinc a day; this is the cause, not a recommended amount.
Who was studied
Case reports of people with excess zinc exposure.
Limits
Case reports only. They cannot say how common this is.
Why researchers looked
Zinc and copper share part of their absorption route, so a lot of zinc from supplements, denture creams or swallowed coins can cause deficiency.
Traditional use
Copper is an essential mineral. Its roles are established nutrition science, not traditional use.
Proposed mechanism Review of lab and human evidence
Zinc competes with copper for absorption (NHS; 2018 review).
A proposed mechanism does not show that the effect happens in people.
Treatment needs a clinician; do not add copper on your own to balance zinc.
Cholesterol and heart-health blood markers (in people not shown to be deficient)
Low certaintyCopper supplements did not change cholesterol in a pooled analysis of 5 trials, and an 8-week trial found no consistent change in heart-health markers.
2 studiesCopper glycinate supplement in the 2012 trial; other trials' forms no…
Studies, doses and limits
What the trials found
A 2012 randomised trial in healthy middle-aged adults with moderately high cholesterol gave copper glycinate or placebo for 8 weeks. Copper raised two copper-enzyme activities but did not significantly change CRP, homocysteine, or total, LDL or HDL cholesterol. Oxidized LDL fell, but the authors called the result inconsistent. A 2021 meta-analysis of 5 trials (176 people) found no significant change in total, LDL or HDL cholesterol.
Results
Copper supplements did not clearly improve cholesterol or the other heart markers measured. It did what copper is expected to do on copper enzymes.
Effect sizes as reported
Meta-analysis, standardised mean differences: total cholesterol -0.05 (-0.52 to 0.43); LDL 0.22 (-0.46 to 0.89); HDL 0.18 (-0.14 to 0.49).
Why this rating
Low that copper changes these markers: the trials found no clear effect, but the 5 trials were small, so a real effect might be missed.
Form and dose studied
Copper glycinate supplement in the 2012 trial; other trials' forms not given in the abstract.
Who was studied
Adults, not shown to be deficient.
Limits
Few, small, short trials. No trial measured heart attacks or strokes.
Why researchers looked
Some researchers have suggested mild copper shortfalls could affect heart risk, so trials tested supplements on cholesterol and related markers.
Traditional use
Copper is an essential mineral. Its roles are established nutrition science, not traditional use.
Proposed mechanism Human trial
Copper raised the activity of two copper enzymes in the trial (superoxide dismutase 1 and ceruloplasmin), but this did not translate to better heart markers.
A proposed mechanism does not show that the effect happens in people.
Do not use copper supplements for heart health; see Safety for the blood-copper link to heart disease.
Heart disease and death: high blood copper (a warning sign, not a benefit)
Moderate certaintyIn large cohorts, people with higher copper in the blood had more strokes and more deaths from heart disease and from any cause.
1 studiesNot applicable: a blood measurement, not a product.
Studies, doses and limits
What the trials found
A 2024 meta-analysis of 17 cohorts (47,813 people) found higher circulating copper linked to more stroke, coronary artery disease death, cardiovascular death and death from any cause, with moderate certainty by GRADE. It did not clearly link to heart attack (low certainty). This is blood copper, not copper eaten or taken.
Results
Stroke OR 1.52 (1.30 to 1.78); coronary artery disease mortality RR 2.77 (1.82 to 4.19); cardiovascular mortality RR 1.79 (1.52 to 2.11); all-cause mortality RR 1.56 (1.35 to 1.79); heart attack RR 2.01 (0.63 to 6.47, not significant).
Effect sizes as reported
Effect sizes as above; per 20 micrograms per decilitre increase, stroke OR 1.23, cardiovascular mortality HR 1.28, all-cause mortality HR 1.22.
Why this rating
Moderate for the link (GRADE as rated by the reviewers) but it is an association; it does not show copper causes the harm.
Who was studied
Adults in 17 cohort studies.
Limits
Observational. Illness and inflammation raise blood copper, so reverse causation is likely. It does not tell anyone to avoid copper in food.
Why researchers looked
Researchers asked whether copper levels in the blood predict heart disease.
Traditional use
Copper is an essential mineral. Its roles are established nutrition science, not traditional use.
Proposed mechanism Observational human
Not established. Blood copper rises with inflammation and illness, so it may be a marker rather than a cause.
A proposed mechanism does not show that the effect happens in people.
No study read says copper supplements raise heart risk.
Bone density
Low certaintyPeople who ate more copper had slightly denser bones in the spine, but the hip result was not clear. This was observational.
2 studiesDietary intake from food in the studies.
Studies, doses and limits
What the trials found
A 2025 meta-analysis of observational studies found higher dietary copper intake went with a modest increase in lumbar spine bone density (3 studies, 9,059 people). The hip difference was similar in size but not statistically significant (4 studies, 14,345 people).
Results
Differences were tiny and no trial of copper supplements on bone was read.
Effect sizes as reported
Lumbar spine MD 0.02 g/cm2 (0.00 to 0.04, p = 0.04); hip MD 0.02 g/cm2 (-0.00 to 0.04, p = 0.07).
Why this rating
Low: observational, few studies, and large differences between studies for the hip (I2 74%).
Form and dose studied
Dietary intake from food in the studies.
Who was studied
Adults in observational studies.
Limits
Does not show that copper causes stronger bones. A small difference of 0.02 g/cm2.
Why researchers looked
Copper helps form the cross-links in collagen that give bone its strength, and deficiency may lead to osteoporosis (MedlinePlus).
Traditional use
Copper is an essential mineral. Its roles are established nutrition science, not traditional use.
Proposed mechanism Observational human
Copper's role in collagen cross-linking and bone formation (as stated in the 2025 review).
A proposed mechanism does not show that the effect happens in people.
Low copper may lead to osteoporosis (MedlinePlus); this is a deficiency link, not a reason to supplement.
Thinking, memory and Alzheimer's disease
Very low certaintyEating very little copper went with faster thinking decline in older Chinese adults, but extra copper above about 1.3 mg a day added nothing. Blood copper is higher in people with Alzheimer's, and no trial tested copper for it.
2 studiesDietary copper (cohort); blood copper measurements (meta-analysis).
Studies, doses and limits
What the trials found
A 2023 cohort of 3,106 Chinese adults aged 55 and older found a non-linear link: those under about 1.28 mg of dietary copper a day declined faster than those above it, with no further benefit above about 1.3 mg. A 2021 meta-analysis of 56 studies found lower copper in Alzheimer's brain samples, higher copper and non-ceruloplasmin copper in blood, and blood copper excess went with three to fourfold higher odds of having Alzheimer's.
Results
No trial of copper supplements for thinking or Alzheimer's was found. The two results point in different directions (a low intake linked to faster decline; excess blood copper linked to Alzheimer's) and neither shows cause.
Effect sizes as reported
Cohort: B 0.30 (0.13 to 0.47) slower decline in higher-intake groups. Meta-analysis: three to fourfold higher odds with serum or plasma copper excess (no CI in abstract).
Why this rating
Very low: observational only, one country for the cohort, and the blood-copper study measures people who already have the disease. Industry link flagged below.
Form and dose studied
Dietary copper (cohort); blood copper measurements (meta-analysis).
Who was studied
Older adults in China; people with Alzheimer's disease and controls.
Limits
Associations only. The first author of the Alzheimer's meta-analysis is Chief Scientific Officer and a shareholder of IGEA Pharma N.V. (a company), which is a possible conflict.
Why researchers looked
Copper is needed by the nervous system, and researchers noticed copper imbalance in Alzheimer's disease.
Traditional use
Copper is an essential mineral. Its roles are established nutrition science, not traditional use.
Proposed mechanism Observational human
Not established. The Alzheimer's meta-analysis found lower brain copper but higher blood copper.
A proposed mechanism does not show that the effect happens in people.
Do not take copper for memory. Excess copper is harmful; see Safety.
Menkes disease (a rare inherited copper disorder)
Moderate certaintyIn Menkes disease, babies cannot move copper around the body. Injected copper-histidine, started within days of birth, improved survival and nerve outcomes in the evidence reviewed.
2 studiesInjected copper-histidine under specialist care; not for ordinary use.
Studies, doses and limits
What the trials found
A 2019 systematic review and guideline (13 articles, GRADE) said copper-histidine is effective for survival and to reduce the nerve burden if started in the newborn period, and that the treatment works only when started within days after birth.
Results
A specialist treatment given by injection, not a food or supplement. It is mentioned here only because Menkes disease is the classic copper disorder.
Effect sizes as reported
No numbers in the abstract.
Why this rating
Moderate: a graded guideline built on a very small evidence base (13 articles) in a very rare disease.
Form and dose studied
Injected copper-histidine under specialist care; not for ordinary use.
Who was studied
Newborns with Menkes disease.
Limits
Rare disease, small evidence base. Not relevant to people eating a normal diet.
Why researchers looked
Menkes disease is a rare X-linked condition of copper metabolism, present before birth in male infants (MedlinePlus). It is not caused by diet.
Traditional use
Copper is an essential mineral. Its roles are established nutrition science, not traditional use.
Proposed mechanism Review of lab and human evidence
A defect in copper handling (the ATP7A pump is named in the 2018 review for gut copper release).
A proposed mechanism does not show that the effect happens in people.
Specialist care only.
Connections to the rest of health
How Copper connects to the rest of our health knowledge graph. Every link says what kind of connection it is. A safety link (for example to the liver) is a warning, not a benefit. A study that merely mentions a topic never creates a benefit link.
Explore every connection: goals, body systems, organs, symptoms, genes
A. Wellness goals
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Preventive Wellness | High certainty | Food sources of copper (nutrient content): Copper is found in shellfish, organ meats, nuts, seeds, whole grains, beans, potatoes and cocoa. USDA tables give the amounts for common foods. | 14 16 20 19 23 18 22 21 24 25 | |
| Energy Boost | Moderate certainty | Correcting copper deficiency: anemia and low blood cells: When someone is truly low in copper, giving copper brings the blood counts back. The blood effects were fully reversible over about 4 to 12 weeks in a review. | 8 1 14 16 | |
| Brain Health | Low certainty | Nerve and spinal cord problems from deficiency: Low copper can damage nerves and the spinal cord (called myeloneuropathy). Copper replacement helps only partly: nerve damage was only partially reversible. | 8 1 3 | |
| Preventive Wellness | Low certainty | Copper deficiency after gastric bypass surgery: Gastric bypass can leave people low in copper. A review found that adequately supplemented patients rarely become deficient, and deficiency can be treated when found. | 6 1 | |
| Preventive Wellness | Low certainty | Copper deficiency caused by too much zinc: Taking high amounts of zinc blocks copper absorption. A review of 37 case reports found low copper in every patient and recovery of blood counts in most once zinc was stopped and copper given. | 3 16 8 | |
| Heart Health | Low certainty | Cholesterol and heart-health blood markers (in people not shown to be deficient): Copper supplements did not change cholesterol in a pooled analysis of 5 trials, and an 8-week trial found no consistent change in heart-health markers. | 2 11 | |
| Cholesterol Balance | Low certainty | Cholesterol and heart-health blood markers (in people not shown to be deficient): Copper supplements did not change cholesterol in a pooled analysis of 5 trials, and an 8-week trial found no consistent change in heart-health markers. | 2 11 | |
| Heart Health | Moderate certainty | Heart disease and death: high blood copper (a warning sign, not a benefit): In large cohorts, people with higher copper in the blood had more strokes and more deaths from heart disease and from any cause. | 12 | |
| Bone Health | Low certainty | Bone density: People who ate more copper had slightly denser bones in the spine, but the hip result was not clear. This was observational. | 5 14 | |
| Brain Health | Very low certainty | Thinking, memory and Alzheimer's disease: Eating very little copper went with faster thinking decline in older Chinese adults, but extra copper above about 1.3 mg a day added nothing. Blood copper is higher in people with Alzheimer's, and no trial tested copper for it. | 7 9 | |
| Memory Support | Very low certainty | Thinking, memory and Alzheimer's disease: Eating very little copper went with faster thinking decline in older Chinese adults, but extra copper above about 1.3 mg a day added nothing. Blood copper is higher in people with Alzheimer's, and no trial tested copper for it. | 7 9 | |
| Preventive Wellness | Moderate certainty | Menkes disease (a rare inherited copper disorder): In Menkes disease, babies cannot move copper around the body. Injected copper-histidine, started within days of birth, improved survival and nerve outcomes in the evidence reviewed. | 10 14 |
B. Body systems
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Musculoskeletal System | Biological association | High certainty | Studied for: Food sources of copper (nutrient content) Studied for: Bone density | 14 16 20 19 23 18 22 21 24 25 5 |
| Nervous System | Biological association | High certainty | Studied for: Food sources of copper (nutrient content) Studied for: Nerve and spinal cord problems from deficiency | 14 16 20 19 23 18 22 21 24 25 8 1 3 6 7 9 10 |
| Heart Circulation | Biological association | Moderate certainty | Studied for: Correcting copper deficiency: anemia and low blood cells Studied for: Copper deficiency after gastric bypass surgery | 8 1 14 16 6 3 |
| Cardiovascular System | Biological association | Low certainty | Studied for: Cholesterol and heart-health blood markers (in people not shown to be deficient) Studied for: Heart disease and death: high blood copper (a warning sign, not a benefit) | 2 11 12 |
E. Health conditions
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Anemia (copper-deficiency anemia) | Established clinical | Too little copper can cause anemia, which reverses with copper replacement over 4 to 12 weeks. Preparation or compound: Copper |
8 14 | |
| Wilson disease | Documented risk | People with Wilson disease cannot remove extra copper and should not take copper-containing multivitamins. Preparation or compound: Copper |
15 4 | |
| Menkes disease | Documented | A very rare inherited disorder of copper handling in male infants. Preparation or compound: Copper |
14 10 |
I. Biomarkers
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Serum copper | Biological association | Low certainty | Measured in trials: low in deficiency; raised back by replacement. A lab change is not the same as a health benefit. | 8 3 |
| Ceruloplasmin | Biological association | Low certainty | Measured in trials: low in deficiency. A lab change is not the same as a health benefit. | 8 4 |
| Blood counts (anemia, white cells) | Biological association | Moderate certainty | Measured in trials: recovered with copper in deficiency. A lab change is not the same as a health benefit. | 8 3 |
| Total, LDL and HDL cholesterol | Biological association | Low certainty | Measured in trials: no significant change. A lab change is not the same as a health benefit. | 11 2 |
| Oxidized LDL | Biological association | Very low certainty | Measured in trials: lowered (inconsistent). A lab change is not the same as a health benefit. | 2 |
| C-reactive protein and homocysteine | Biological association | Low certainty | Measured in trials: no significant change. A lab change is not the same as a health benefit. | 2 |
| Copper enzyme activity (superoxide dismutase 1, ceruloplasmin) | Biological association | Low certainty | Measured in trials: raised. A lab change is not the same as a health benefit. | 2 |
| Bone mineral density (spine and hip) | Biological association | Low certainty | Measured in trials: slightly higher in the spine with higher intake (observational). A lab change is not the same as a health benefit. | 5 |
J. Genes, receptors and enzymes
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| ATP7A | Preliminary mechanism | Human | Copper export pump in gut cells, named in the 2018 review. Menkes disease is a disorder of copper handling; the abstracts read do not name its gene. | 8 |
| ATP7B | Preliminary mechanism | Human | Copper transporter studied in Alzheimer's disease in the 2021 replication study; Wilson disease is the disorder of copper handling. | 9 4 |
K. Biological pathways
L. Active compounds
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Copper gluconate | Biological association | Human | Named in the 2018 review as a form used to replace copper in deficiency anemia, orally or by vein. | 8 |
| Copper sulfate and copper chloride | Biological association | Human | Also named in the 2018 review for replacement in deficiency anemia. | 8 |
| Copper glycinate | Biological association | Human | The form used in the 2012 randomised trial; it raised copper enzyme activity but did not consistently change heart markers. | 2 |
| Copper-histidine | Biological association | Human | Injected treatment for Menkes disease when started in the newborn period. | 10 |
| Cupric oxide and other forms in multivitamins | Biological association | Summary only | Listed in the existing nutrient summary only. No source read compared forms for absorption or effect. | 14 |
Each connection is stored with the ingredient, the connected record, the kind of connection, the evidence status, the supporting studies, the preparation or compound involved, and a review date (last reviewed October 26, 2026).
Evidence at a glance: what changed in 1 lab markers
Tap a number to show only those markers. Counts are markers, not people.
The evidence
The research centre for Copper. Every record here was checked against PubMed or the publisher's page; we never list a study we have not verified.
Evidence by outcome
Bars show how many studies we found for each outcome, not how well it works. People are added up across trials only (reviews are not added, to avoid double counting).
How we rate evidence
High certainty
Several well-run trials or reviews agree; further research is unlikely to change the picture much.
Moderate certainty
Good trials point the same way, but some doubt remains.
Low certainty
Small, short or inconsistent trials. The finding could change with better research.
Very low certainty
Very little or very weak human data. Treat as a possibility only.
Mixed findings
Trials or reviews disagree with each other.
Not enough evidence
Not enough human research to say either way.
Evidence against
Good research found no benefit, or found harm.
We take the reviewers' own risk-of-bias and GRADE statements where they exist, and otherwise judge from study size, design, consistency, directness and whether a product matches what is sold. Many publications do not make evidence high. Method note: We started from our existing copper summary, read the MedlinePlus, NHS and EFSA pages, re-checked food values against saved USDA FoodData Central data, and read PubMed abstracts for the reviews, trials and cohorts cited. Only abstracts were read for studies. Items we could not verify are flagged in the research gaps.
Study library: every study we checked 25
| Study | Design | People | Product, dose, length | Result |
|---|---|---|---|---|
| Altarelli 2019 Copper Deficiency: Causes, Manifestations, and Treatment. Nutr Clin Pract · PMID 31209935 · DOI |
Narrative review |
Literature review (PubMed and Cochrane) of copper deficiency | Copper (oral or intravenous repletion described) |
Deficiency can be inherited or acquired, and acquired is the most common. Signs are non-specific but mainly affect the blood (anemia) and the nerves (myeloneuropathy), and also the cardiovascular, skin and immune systems. Severe deficiency after gastric bypass surgery has become frequent. Reduced absorption after bypass surgery and prolonged continuous kidney replacement therapy in hospital are named as causes. No numbers in the abstract (Not applicable) Methods, limits and fundingOutcomes: Causes, manifestations and treatment of copper deficiency Limitations: A narrative review, so it does not pool data or grade the evidence. The abstract gives healthy adult needs as 0.9 mg a day. Funding and conflicts: Funding is not stated in the abstract. Read: abstract |
| DiSilvestro 2012 A randomized trial of copper supplementation effects on blood copper enzyme activities and parameters related to cardiovascular health. Metabolism · PMID 22444781 · DOI |
Randomised controlled trial |
Healthy middle-aged US adults with moderately high cholesterol | Copper glycinate supplement 2 mg of copper a day (as studied in the trial) 8 weeks · vs Placebo |
Copper raised the activity of two copper enzymes. Five heart-related blood measures (CRP, homocysteine, total, LDL and HDL cholesterol) did not change significantly. Oxidized LDL was lower, a statistically significant but inconsistent result. The authors concluded copper did not consistently improve the heart-health measures studied. No numbers in the abstract (Not applicable) Methods, limits and fundingOutcomes: Copper enzyme activity (erythrocyte superoxide dismutase 1, plasma ceruloplasmin); C-reactive protein, homocysteine, total, LDL and HDL cholesterol; oxidized LDL Limitations: Short (8 weeks), adults who were not shown to be copper-deficient. Sample size is not given in the abstract. Oxidized LDL result was described as inconsistent. Funding and conflicts: PubMed lists US government (non-PHS) research support; no company is named in the abstract. Read: abstract |
| Dutta 2026 Zinc-Induced Hematologic Toxicities: A Systematic Review of Descriptive Studies. Biol Trace Elem Res · PMID 42087025 · DOI |
Systematic review case reports |
37 34 publications describing 37 individual cases (1972 to 2025) of anemia or other blood-cell problems attributed to zinc |
Zinc exposure (oral supplements, denture adhesive creams, coin ingestion); copper replacement was the treatment Zinc exposure ranged from about 50 mg to over 1500 mg of elemental zinc a day (this is the cause, not a recommended amount) Weeks to years of zinc exposure |
Anemia was present in nearly all cases, often with low neutrophils and white cells, and pancytopenia in severe or prolonged exposure. Serum copper was low in all patients. Bone marrow often looked like myelodysplastic syndrome at first. Stopping zinc and giving copper led to blood recovery in most cases within weeks to months; nerve problems improved more slowly and were sometimes incomplete. Serum copper reduced in all patients; blood recovery in the majority (Not applicable) Methods, limits and fundingOutcomes: Blood-cell problems, serum copper, recovery Limitations: Case reports and case series only, so no rates and no proof of how common this is. The authors call it uncommon. Funding and conflicts: Funding is not stated in the abstract. Read: abstract |
| European Association for the Study of the Liver 2025 EASL-ERN Clinical Practice Guidelines on Wilson's disease. J Hepatol · PMID 40089450 · DOI |
Clinical practice guideline |
People with Wilson's disease, an inherited disorder of copper handling | Copper-lowering treatment: chelating agents (penicillamine, trientine) and zinc salts Lifelong monitoring is described |
Wilson's disease is an inherited disorder of copper metabolism that affects the liver, brain and other organs. Diagnosis uses ceruloplasmin, 24-hour urinary copper, liver copper and genetic tests. Treatment uses chelators and zinc salts, and only chelators are recommended for significant liver disease. Acute liver failure can need a liver transplant. No numbers in the abstract (Not applicable) Methods, limits and fundingOutcomes: Diagnosis and treatment of Wilson's disease Limitations: A guideline for specialists. The abstract says nothing about copper supplements; that point comes from MedlinePlus. Funding and conflicts: Funding is not stated in the abstract. Read: abstract |
| Gutiérrez-Guerra 2025 Dietary Copper Intake and Bone Health: A Systematic Review and Meta-Analysis of Observational Studies. Calcif Tissue Int · PMID 41361655 · DOI |
Systematic review meta analysis |
14345 Observational studies of dietary copper intake and DXA-measured bone density (3 studies, n = 9059 for lumbar spine; 4 studies, n = 14,345 for hip) |
Dietary copper intake (from food), not a supplement · vs Lower dietary copper intake |
Higher dietary copper intake went with a slightly higher lumbar spine bone density. The hip result was similar in size but not statistically significant. Lumbar spine MD 0.02 g/cm2 (p = 0.04, I2 36%); hip MD 0.02 g/cm2 (p = 0.07, I2 74%) (Lumbar 0.00 to 0.04; hip -0.00 to 0.04) Methods, limits and fundingOutcomes: Lumbar spine and hip bone mineral density Limitations: Very few studies, observational, and the hip result varied a lot between studies. Registered in PROSPERO (CRD42024617075). Food diaries are imprecise. Cannot show that copper itself caused the difference. Funding and conflicts: The authors declare no conflicts of interest. Registration: PROSPERO CRD42024617075 Read: abstract |
| Kumar 2016 Copper Deficiency after Gastric Bypass for Morbid Obesity: a Systematic Review. Obes Surg · PMID 27034062 · DOI |
Systematic review |
People who had gastric bypass or other weight-loss surgery | Copper supplementation after surgery (as described by the review) |
Many people having weight-loss surgery are already low in copper and bypass can make it worse. The review concluded copper deficiency in adequately supplemented patients is rare and can be treated if a related blood or nerve disorder is found. Routine testing may not be justified for adequately supplemented people without symptoms, but may be needed for high-risk groups. No numbers in the abstract (Not applicable) Methods, limits and fundingOutcomes: Copper deficiency after Roux-en-Y gastric bypass; value of routine monitoring Limitations: The abstract gives no counts. The review calls for annual testing in some UK guidance but argues against routine testing in everyone. Funding and conflicts: Funding is not stated in the abstract. Read: abstract |
| Meng 2023 Association Between Dietary Copper Intake and Cognitive Decline: A Perspective Cohort Study in Chinese Elderly. Am J Geriatr Psychiatry · PMID 37263860 · DOI |
Prospective cohort |
3106 3,106 Chinese adults aged 55 or older in the China Health and Nutrition Survey, median follow-up 5.9 years |
Dietary copper intake (from food), measured by 24-hour dietary recalls Median 5.9 years · vs People in the lowest intake group (under 1.28 mg a day) |
The link was not a straight line. People in the lowest intake group (under 1.28 mg a day) had faster decline in thinking scores than those above it. Above about 1.3 mg a day the benefit did not keep growing. Slower decline in composite cognitive score for the higher groups: B 0.30 (0.13 to 0.47) Methods, limits and fundingOutcomes: 5-year change in cognitive scores (TICS-m) Limitations: Observational, one country, memory-based food records. Other diet and lifestyle differences may explain part of the link. Cannot show that eating more copper protects thinking. Funding and conflicts: PubMed lists NIH extramural and non-US government research support; no company is named in the abstract. Read: abstract |
| Myint 2018 Copper deficiency anemia: review article. Ann Hematol · PMID 29959467 · DOI |
Narrative review |
Review of copper deficiency and its blood and nerve effects | Copper replacement (oral or intravenous copper gluconate, copper sulfate or copper chloride) Blood effects reversed over 4 to 12 weeks, as stated in the abstract |
Deficiency affects bone marrow blood-cell production, optic nerve function and the nervous system. Diagnosis uses serum copper, serum ceruloplasmin and 24-hour urine copper. Treatment is oral or intravenous copper replacement. Blood problems are fully reversible over 4 to 12 weeks; nerve problems are only partly reversible. No numbers in the abstract (Not applicable) Methods, limits and fundingOutcomes: Causes, diagnosis and treatment of copper deficiency anemia; effects on bone marrow, optic nerve and nervous system Limitations: A narrative review, not a trial. It does not pool data. It says deficiency has been seen more often in recent decades. Funding and conflicts: Funding is not stated in the abstract. Read: abstract |
| Squitti 2021 Copper Imbalance in Alzheimer's Disease: Meta-Analysis of Serum, Plasma, and Brain Specimens, and Replication Study Evaluating ATP7B Gene Variants. Biomolecules · PMID 34209820 · DOI |
Systematic review meta analysis |
56 studies: brain samples (182 people with Alzheimer's and 166 healthy controls) and serum or plasma (2,929 with Alzheimer's and 3,547 controls); plus a replication study of 97 patients and 70 controls | Copper measured in blood and brain, not given as treatment · vs Healthy controls |
Brain copper was lower in Alzheimer's disease, while blood copper and non-ceruloplasmin copper were higher and ceruloplasmin was unchanged. Blood copper excess went with a three to fourfold higher risk of having Alzheimer's. The authors suggest copper balance is disturbed in a subset of patients. Serum or plasma copper excess associated with a three to fourfold higher risk of having Alzheimer's (Not given in the abstract) Methods, limits and fundingOutcomes: Copper in brain and blood in Alzheimer's disease Limitations: Measures copper in people who already have the disease, so it cannot show whether copper imbalance causes it. It says nothing about taking copper. Not a trial. Funding and conflicts: The first author is Chief Scientific Officer and shareholder of IGEA Pharma N.V., a company; the other authors declare no conflicts. Read: abstract |
| Vairo 2019 A systematic review and evidence-based guideline for diagnosis and treatment of Menkes disease. Mol Genet Metab · PMID 30594472 · DOI |
Systematic review guideline |
Babies and children with Menkes disease, a rare inherited copper-handling disorder (13 articles used) | Injected copper-histidine (a prescription treatment, not a supplement) Started in the newborn period |
Treatment with copper-histidine was judged effective to increase survival and reduce the nerve burden if started in the newborn period. Evidence suggests it works only when started within days after birth. Treatment should not be guided by the child's genotype. No numbers in the abstract (Not applicable) Methods, limits and fundingOutcomes: Survival and nerve outcomes in Menkes disease Limitations: Very rare disease, so the evidence base is small (13 articles). This is a prescribed injection under specialist care, not a food or pill. Funding and conflicts: Funding is not stated in the abstract. Read: abstract |
| Wang 2021 Effects of Copper Supplementation on Blood Lipid Level: a Systematic Review and a Meta-Analysis on Randomized Clinical Trials. Biol Trace Elem Res · PMID 33030656 · DOI |
Systematic review meta analysis |
176 5 randomised trials, 176 participants (searched to January 2020) |
Copper supplements Trial amounts not given in the abstract Not given in the abstract · vs Control (no copper) |
Copper supplements made no significant difference to total, LDL or HDL cholesterol compared with control. Total cholesterol SMD -0.05; LDL SMD 0.22; HDL SMD 0.18 (Total -0.52 to 0.43; LDL -0.46 to 0.89; HDL -0.14 to 0.49) Methods, limits and fundingOutcomes: Total cholesterol, LDL cholesterol, HDL cholesterol Limitations: Only 5 small trials, so a real effect could be missed. The authors say more research is needed. Funding and conflicts: Funding is not stated in the abstract. Read: abstract |
| Zhao 2024 Circulating copper levels and the risk of cardio-cerebrovascular diseases and cardiovascular and all-cause mortality: A systematic review and meta-analysis of longitudinal studies. Environ Pollut · PMID 37852312 · DOI |
Systematic review meta analysis |
47813 47,813 people in 17 cohort studies (searched to 23 August 2023) |
Blood (circulating) copper level, measured, not taken as a supplement Cohort follow-up · vs Lower circulating copper |
Higher blood copper went with more stroke, more coronary artery disease death, more cardiovascular death and more death from any cause, with moderate certainty by GRADE. It did not clearly link to heart attack (low certainty). Stroke OR 1.52; coronary artery disease mortality RR 2.77; cardiovascular mortality RR 1.79; all-cause mortality RR 1.56; heart attack RR 2.01 (not significant) (Stroke 1.30 to 1.78; CAD mortality 1.82 to 4.19; CV mortality 1.52 to 2.11; all-cause 1.35 to 1.79; heart attack 0.63 to 6.47) Methods, limits and fundingOutcomes: Stroke, coronary artery disease mortality, cardiovascular mortality, all-cause mortality, heart attack Limitations: Blood copper rises with inflammation and illness, so it may be a marker rather than a cause. It measures copper in the blood, not how much copper someone ate or took. Observational, cannot show cause. Funding and conflicts: The authors declare writing assistance (non-financial support) for one author; no industry funding is stated in the abstract. Read: abstract |
| s-efsa-ul EFSA: Overview on Tolerable Upper Intake Levels as derived by the SCF and the EFSA NDA Panel, version 11 (August 2025) · Source |
Authoritative guidance n/a |
Methods, limits and fundingRead: full-text | ||
| s-medlineplus-copper MedlinePlus: Copper in diet (review date 1/21/2025) · Source |
Authoritative guidance n/a |
Methods, limits and fundingRead: full-text | ||
| s-medlineplus-wilson MedlinePlus: Wilson Disease (health topic) · Source |
Authoritative guidance n/a |
Methods, limits and fundingRead: full-text | ||
| s-nhs-others NHS: Vitamins and minerals - Others (copper section; page last reviewed 3 August 2020) · Source |
Authoritative guidance n/a |
Methods, limits and fundingRead: full-text | ||
| s-ods-copper NIH Office of Dietary Supplements: Copper fact sheet for health professionals · Source |
Authoritative guidance n/a |
Methods, limits and fundingRead: not-read | ||
| s-usda-fdc-169593 USDA FoodData Central: Cocoa, dry powder, unsweetened (FDC 169593, SR Legacy, April 2018) · Source |
Reference database n/a |
Methods, limits and fundingRead: full-text | ||
| s-usda-fdc-170150 USDA FoodData Central: Seeds, sesame seeds, whole, dried (FDC 170150, SR Legacy, April 2018) · Source |
Reference database n/a |
Methods, limits and fundingRead: full-text | ||
| s-usda-fdc-170162 USDA FoodData Central: Nuts, cashew nuts, raw (FDC 170162, SR Legacy, April 2018) · Source |
Reference database n/a |
Methods, limits and fundingRead: full-text | ||
| s-usda-fdc-170187 USDA FoodData Central: Nuts, walnuts, english (FDC 170187, SR Legacy, April 2018) · Source |
Reference database n/a |
Methods, limits and fundingRead: full-text | ||
| s-usda-fdc-170556 USDA FoodData Central: Seeds, pumpkin and squash seed kernels, dried (FDC 170556, SR Legacy, April 2018) · Source |
Reference database n/a |
Methods, limits and fundingRead: full-text | ||
| s-usda-fdc-170562 USDA FoodData Central: Seeds, sunflower seed kernels, dried (FDC 170562, SR Legacy, April 2018) · Source |
Reference database n/a |
Methods, limits and fundingRead: full-text | ||
| s-usda-fdc-172421 USDA FoodData Central: Lentils, mature seeds, cooked, boiled, without salt (FDC 172421, SR Legacy, April 2018) · Source |
Reference database n/a |
Methods, limits and fundingRead: full-text | ||
| s-usda-fdc-173757 USDA FoodData Central: Chickpeas (garbanzo beans, bengal gram), mature seeds, cooked, boiled, without salt (FDC 173757, SR Legacy, April 2018) · Source |
Reference database n/a |
Methods, limits and fundingRead: full-text |
What we do not know yet
- No randomised trial of copper replacement for deficiency anemia or nerve damage was read, and no trial of copper supplements for bone, thinking, immunity or heart events was found.
- The blood-copper and heart results are observational and cannot show cause.
- The NIH Office of Dietary Supplements fact sheet was blocked, so the US upper limit and its interaction list are not given.
- Copper in shellfish and organ meats, absorption from foods versus supplements, supplement contamination, and safety in pregnancy, breastfeeding and children were not covered by the sources read.
How new research is added
New studies are found by a saved PubMed search and placed in a review queue before the page changes.
Lab markers
What changed in blood or saliva tests during trials. A changed number is not the same as feeling or being healthier, and we give no "normal ranges".
Other 8
Serum copper
Low in deficiency; raised back by replacement in trials
The amount of copper in the blood liquid.
Low certaintyResults and what it means
Why it was measured
It is one of the tests used to diagnose copper deficiency.
Statistical vs. clinical meaning
A low reading plus a matching blood or nerve picture points to deficiency. Interpretation needs a clinician; high readings are discussed on the Health Benefits tab.
Safety implication
High blood copper is linked to heart disease and death in observational studies; see Health Benefits.
| Study | Result | People | Product |
|---|---|---|---|
| 8 | Diagnosis of copper deficiency is made by measuring serum copper, serum ceruloplasmin and 24-hour urine copper; blood effects reverse over 4 to 12 weeks of replacement | People with copper deficiency (review) | Oral or intravenous copper replacement |
| 3 | Serum copper was reduced in all 37 patients with zinc-related blood problems | 37 case reports | Excess zinc exposure |
Ceruloplasmin
Low in deficiency in trials
A blood protein that carries most of the copper in blood.
Low certaintyResults and what it means
Why it was measured
It is tested with serum copper to diagnose deficiency, and in Wilson's disease.
Statistical vs. clinical meaning
Used by clinicians as part of diagnosis; the abstracts give no cut-off values.
Safety implication
None specific.
Blood counts (anemia, white cells)
Recovered with copper in deficiency in trials
Hemoglobin and blood-cell counts that show anemia or low white cells.
Moderate certaintyResults and what it means
Why it was measured
Anemia and low white cells are the blood signs of copper deficiency.
Statistical vs. clinical meaning
The most reliable benefit of copper replacement, and only in deficient people.
Safety implication
Anemia has many causes; do not self-treat.
| Study | Result | People | Product |
|---|---|---|---|
| 8 | Hematological manifestations fully reversible over 4 to 12 weeks of copper replacement | People with copper deficiency anemia (review) | Oral or intravenous copper |
| 3 | Blood recovery in the majority once zinc was stopped and copper given, typically within weeks to months | 37 cases of zinc-related blood toxicity | Stop zinc, give copper |
Total, LDL and HDL cholesterol
No significant change in trials
Fats in the blood used to estimate heart risk.
Low certaintyResults and what it means
Why it was measured
Trials tested whether copper supplements change cholesterol.
Statistical vs. clinical meaning
No clear effect, but few small trials.
Safety implication
None specific.
| Study | Result | People | Product |
|---|---|---|---|
| 11 | Total cholesterol SMD -0.05 (-0.52 to 0.43); LDL 0.22 (-0.46 to 0.89); HDL 0.18 (-0.14 to 0.49) | 5 randomised trials, 176 people | Copper supplements versus control |
| 2 | Total, LDL and HDL cholesterol did not change significantly | Healthy middle-aged adults with moderately high cholesterol | 2 mg of copper a day (as copper glycinate) for 8 weeks versus placebo |
Oxidized LDL
Lowered (inconsistent) in trials
LDL cholesterol that has been chemically damaged, thought to be more harmful.
Very low certaintyResults and what it means
Why it was measured
Copper enzymes protect against oxidative damage, so researchers looked at it.
Statistical vs. clinical meaning
A single small trial with an inconsistent result; not a proven benefit.
Safety implication
None specific.
| Study | Result | People | Product |
|---|---|---|---|
| 2 | Mean oxidized LDL was lower with copper, statistically significant but described as inconsistent | Healthy middle-aged adults with moderately high cholesterol | 2 mg of copper a day (as copper glycinate) for 8 weeks versus placebo |
C-reactive protein and homocysteine
No significant change in trials
CRP is a blood marker of inflammation; homocysteine is an amino acid linked to heart risk.
Low certaintyResults and what it means
Why it was measured
Used as heart-risk markers in the copper trial.
Statistical vs. clinical meaning
No effect seen in one 8-week trial.
Safety implication
None specific.
| Study | Result | People | Product |
|---|---|---|---|
| 2 | CRP and homocysteine were not changed significantly by copper | Healthy middle-aged adults with moderately high cholesterol | 2 mg of copper a day (as copper glycinate) for 8 weeks versus placebo |
Copper enzyme activity (superoxide dismutase 1, ceruloplasmin)
Raised in trials
Activity of two enzymes that need copper to work.
Low certaintyResults and what it means
Why it was measured
To show whether extra copper changed how well copper enzymes work.
Statistical vs. clinical meaning
Shows the supplement was absorbed and active, not that health improved.
Safety implication
None specific.
| Study | Result | People | Product |
|---|---|---|---|
| 2 | Copper raised erythrocyte superoxide dismutase 1 and plasma ceruloplasmin activity; placebo did not | Healthy middle-aged adults with moderately high cholesterol | 2 mg of copper a day (as copper glycinate) for 8 weeks versus placebo |
Bone mineral density (spine and hip)
Slightly higher in the spine with higher intake (observational) in trials
How dense the bones are, measured by a DXA scan.
Low certaintyResults and what it means
Why it was measured
Used to test whether copper intake relates to bone strength.
Statistical vs. clinical meaning
A very small difference in an observational comparison.
Safety implication
None specific.
| Study | Result | People | Product |
|---|---|---|---|
| 5 | Lumbar spine MD 0.02 g/cm2 (0.00 to 0.04); hip 0.02 g/cm2 (-0.00 to 0.04, not significant) | 3 studies (n = 9,059) for lumbar spine; 4 studies (n = 14,345) for hip | Higher versus lower dietary copper intake |
Safety
What studies and official sources say about side effects, medicines and who should check first. Each point shows what kind of evidence it comes from.
Main points to know 4
- Too much copper is poisonous; deficiency is also harmful. MedlinePlus says people normally get enough copper from food, a lack may lead to anemia and osteoporosis, and in large amounts copper is poisonous. The NHS says high doses could cause stomach pain, sickness and diarrhoea and, if taken for a long time, damage to the liver and kidneys. Authoritative guidance 14 16
- Wilson disease: people with it should not take copper-containing multivitamins. Wilson disease is a rare inherited disorder that stops the body getting rid of extra copper. Copper builds up in the liver, brain, kidneys and eyes. MedlinePlus tells people with it not to take multivitamins that contain copper, and to avoid shellfish and liver. Authoritative guidance 15 4
- High zinc blocks copper and can cause anemia. The NHS says high zinc doses reduce how much copper the body can absorb, which can lead to anaemia and weakening of the bones. A 2026 review of 37 case reports found low copper in every patient and recovery in most once zinc was stopped and copper given. Authoritative guidance and case reports 16 3
- Do not use copper to treat anemia or nerve symptoms yourself. Anemia and nerve symptoms have many causes. Copper deficiency is diagnosed by blood and urine tests, and treatment is directed by a clinician. Review 8 1
Side effects 4
| Effect | How often | Severity and recovery | Evidence |
|---|---|---|---|
| Stomach pain, sickness (nausea) and diarrhoea from high doses The NHS lists these effects for high doses of copper; amounts that cause them are not stated here. | No frequency found | mild to moderate Not described in the sources read. | Authoritative guidance 16 |
| Liver and kidney damage with long-term high doses MedlinePlus says copper is poisonous in large amounts. | No frequency found | can be serious Not described in the sources read. | Authoritative guidance 16 14 |
| Anemia, low white blood cells and nerve damage when copper is too low This is a deficiency effect, not an effect of taking copper. | No frequency found | can be severe Blood effects fully reversible over 4 to 12 weeks with replacement; nerve effects only partly reversible (2018 review). | Review 8 1 |
| Copper build-up in the liver, brain, kidneys and eyes in Wilson disease An inherited condition, not caused by ordinary diet. | Rare inherited disorder; no rate was read. | can be severe Treatment is lifelong and specialist-led. | Authoritative guidance 15 4 |
Liver
The NHS says long-term high copper doses could damage the liver and kidneys. Wilson disease causes copper build-up in the liver and can lead to hepatitis and liver failure; EASL-ERN guidelines describe liver transplant for acute failure. No LiverTox entry for copper was read, so no case-report frequency is stated. 16 15 4
How often. No frequency found.
Monitoring. For Wilson disease, the EASL-ERN guideline describes monitoring by symptoms, liver tests and copper measures. For ordinary supplement users, no agency monitoring advice was read.
This is a safety connection. It is not evidence that Copper supports liver health.
Medicines and supplements 4
| With | Why it matters | Importance | Evidence | What to do |
|---|---|---|---|---|
| Zinc supplements (and zinc products such as denture creams) supplement | Zinc reduces how much copper the body absorbs; the 2018 review notes the two minerals share part of their absorption route. | High zinc can cause copper deficiency with anemia and nerve problems. In 37 case reports serum copper was low in every patient. | Authoritative guidance and case reports Low certainty 16 3 8 | Tell your doctor or pharmacist what zinc you take, including products you do not swallow. Do not add copper on your own to balance zinc. |
| Wilson disease medicines (penicillamine, trientine) and zinc salts used as treatment prescription | These medicines lower the body's copper; they are the treatment for copper overload. | The EASL guideline describes them as the treatment. MedlinePlus tells people with Wilson disease not to take copper-containing multivitamins. | Authoritative guidance Moderate certainty 4 15 | If you are treated for Wilson disease, ask your specialist before any copper or multi-mineral product. |
| Iron supplement | Copper helps release iron so the body can make haemoglobin (NHS, MedlinePlus). | This is a working partnership, not a warning. In copper deficiency, anemia may not respond to iron alone. No harmful interaction was read. | Authoritative guidance Low certainty 16 14 8 | Ask a clinician if anemia does not improve. |
| Other drugs and supplements (for example vitamin C, molybdenum, antacids, some medicines) other | Not read. | The NIH Office of Dietary Supplements interaction list was blocked and not read, so no other interaction is stated here. | Not assessed Not enough evidence 17 | Ask a pharmacist before combining copper with other supplements or medicines. |
Who should check first 2
| Situation | Advice | Evidence |
|---|---|---|
| Wilson disease | Do not take multivitamins that contain copper; specialist advice is needed (MedlinePlus). | Authoritative guidance 15 4 |
| Liver or kidney disease | The NHS says long-term high copper doses can damage the liver and kidneys; ask your doctor before any copper product. | Authoritative guidance 16 |
Overdose, product quality and regulators
Summary. Copper is essential but poisonous in large amounts (MedlinePlus). Stomach upset is the early effect of high doses; long-term high intake can harm the liver and kidneys (NHS).
Animal. Not reviewed.
High dose or long term signals. The NHS names stomach pain, sickness, diarrhoea and, with long-term use, liver and kidney damage.
Overdose response. For a suspected overdose or poisoning, contact a poison centre or emergency services (in the US, Poison Help 1-800-222-1222).
Genotoxicity. Not researched.
Copper in drinking water can add to intake: MedlinePlus advises people with Wilson disease to have their drinking water checked for copper. The NHS 10 mg figure includes copper from food, water and supplements. Label accuracy and contaminants of copper supplements were not found in the sources read.
Drinking water. MedlinePlus advises people with Wilson disease to have drinking water checked for copper content. 15
Total intake. The NHS counts copper from food, water and supplements together when giving its 10 mg figure. 16
| Body | Action | Date |
|---|---|---|
| NHS (UK Department of Health and Social Care advice) (United Kingdom) | Says adults aged 19 to 64 need 1.2 mg of copper a day, that you should be able to get all you need from a varied diet, and that 10 mg or less a day from food, water and supplements is unlikely to cause harm. source | 2020-08-03 |
| EFSA (EU) (European Union) | Overview of tolerable upper intake levels, version 11: the SCF 2003 copper upper level for adults is read as 5 mg a day (total chronic intake from all sources). In 2023 the EFSA Scientific Committee set an acceptable daily intake of 0.07 mg per kg of body weight, a different kind of guidance. source | 2025-08 |
| US National Academies via MedlinePlus (United States) | Reference intakes: RDA 900 micrograms a day for ages 19 and over; 1,000 for pregnancy and 1,300 for breastfeeding; children 340 (1 to 3 years), 440 (4 to 8) and 700 (9 to 13); adequate intake 200 (0 to 6 months) and 220 (7 to 12 months). These are planning figures for healthy people, not advice. source | 2025-01-21 |
| EASL-ERN (Europe) | Clinical practice guideline on Wilson's disease: treatment with chelating agents (penicillamine, trientine) and zinc salts, and monitoring of copper metabolism. source | 2025-02-22 |
When to get medical help
- Severe or lasting stomach pain, vomiting or diarrhoea after swallowing a lot of copper, or after drinking water or food stored in a way that may have added copper: get medical help or call a poison centre (US: 1-800-222-1222).
- New numbness, tingling, weakness or trouble walking, especially with anemia, after weight-loss surgery or long-term high zinc use: see a doctor soon, because nerve damage from copper deficiency is only partly reversible.
- A rusty-brown ring around the cornea of the eye with liver or nervous-system problems (Wilson disease symptoms usually start between ages 5 and 35, per MedlinePlus): see a doctor.
Stop using the product and contact a clinician or emergency service. In the US, Poison Control is 1-800-222-1222.
General information only, not medical advice. Ask a clinician or pharmacist before use, especially with medicines, in pregnancy or with a health condition. See the Natural Remedy Safety guide.
Frequently asked questions
What is copper?
What foods contain copper?
What happens if you do not get enough copper?
Can too much zinc cause copper deficiency?
Does copper help the heart or lower cholesterol?
Is high blood copper a problem?
In 17 cohorts, higher blood copper went with more stroke and cardiovascular death. This is an association; illness raises blood copper, and it does not show that copper in food or supplements causes harm.
Is copper good for bones or memory?
Is there an official upper limit for copper?
Who should avoid copper supplements?
What is Wilson disease?
Can I get copper deficiency after weight-loss surgery?
Are there product or brand recommendations?
No. This page names no products and carries no affiliate links. Ask a doctor or pharmacist about supplements.
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Editorial transparency
- Written by
- AlternativeMed editorial team. Research compiled with AI assistance, then checked against the sources listed.
- Medical review
- None. This page has not been reviewed by a physician or pharmacist.
- First published
- 2026-10-26
- Last substantive update
- 2026-10-26
- How we research
- We started from our existing copper summary, read the MedlinePlus, NHS and EFSA pages, re-checked food values against saved USDA FoodData Central data, and read PubMed abstracts for the reviews, trials and cohorts cited. Only abstracts were read for studies. Items we could not verify are flagged in the research gaps.
- How we rate evidence
- See "How we rate evidence" in the Evidence tab.
- Independence
- No product is promoted on this page. No affiliate links are shown. One Alzheimer's analysis cited has a first author who is an officer of a company (IGEA Pharma N.V.); this is stated where it is used.
Sources 25
Each source was opened and checked. Where we read only the abstract, it says so. The small numbers in the text point here.
- Altarelli M, Ben-Hamouda N, Schneider A, Berger MM. Copper Deficiency: Causes, Manifestations, and Treatment.. Nutr Clin Pract. 2019. PMID 31209935. DOI 10.1002/ncp.10328. (abstract)
- DiSilvestro RA, Joseph EL, Zhang W, Raimo AE, Kim YM. A randomized trial of copper supplementation effects on blood copper enzyme activities and parameters related to cardiovascular health.. Metabolism. 2012. PMID 22444781. DOI 10.1016/j.metabol.2012.02.002. (abstract)
- Dutta A, Chaudhary V, Kumari S, Rohita, Sharma KK, Pal B. Zinc-Induced Hematologic Toxicities: A Systematic Review of Descriptive Studies.. Biol Trace Elem Res. 2026. PMID 42087025. DOI 10.1007/s12011-026-05136-z. (abstract)
- European Association for the Study of the Liver. EASL-ERN Clinical Practice Guidelines on Wilson's disease.. J Hepatol. 2025. PMID 40089450. DOI 10.1016/j.jhep.2024.11.007. (abstract)
- Gutiérrez-Guerra MA, Puerto-Parejo LM, Pastor-Ramón E, Pedrera-Canal M, Vera V, Pedrera-Zamorano JD, Lavado-García JM, López-Espuela F, Roncero-Martín R, Fabregat-Fernández J, Morán JM. Dietary Copper Intake and Bone Health: A Systematic Review and Meta-Analysis of Observational Studies.. Calcif Tissue Int. 2025. PMID 41361655. DOI 10.1007/s00223-025-01463-w. (abstract)
- Kumar P, Hamza N, Madhok B, De Alwis N, Sharma M, Miras AD, Mahawar KK. Copper Deficiency after Gastric Bypass for Morbid Obesity: a Systematic Review.. Obes Surg. 2016. PMID 27034062. DOI 10.1007/s11695-016-2162-8. (abstract)
- Meng Q, Liu C, Zu C, Wei Y, Su X, Gan X, Zhang Y, He P, Zhou C, Liu M, Ye Z, Qin X. Association Between Dietary Copper Intake and Cognitive Decline: A Perspective Cohort Study in Chinese Elderly.. Am J Geriatr Psychiatry. 2023. PMID 37263860. DOI 10.1016/j.jagp.2023.05.001. (abstract)
- Myint ZW, Oo TH, Thein KZ, Tun AM, Saeed H. Copper deficiency anemia: review article.. Ann Hematol. 2018. PMID 29959467. DOI 10.1007/s00277-018-3407-5. (abstract)
- Squitti R, Ventriglia M, Simonelli I, Bonvicini C, Costa A, Perini G, Binetti G, Benussi L, Ghidoni R, Koch G, Borroni B, Albanese A, Sensi SL, Rongioletti M. Copper Imbalance in Alzheimer's Disease: Meta-Analysis of Serum, Plasma, and Brain Specimens, and Replication Study Evaluating ATP7B Gene Variants.. Biomolecules. 2021. PMID 34209820. DOI 10.3390/biom11070960. (abstract)
- Vairo FPE, Chwal BC, Perini S, Ferreira MAP, de Freitas Lopes AC, Saute JAM. A systematic review and evidence-based guideline for diagnosis and treatment of Menkes disease.. Mol Genet Metab. 2019. PMID 30594472. DOI 10.1016/j.ymgme.2018.12.005. (abstract)
- Wang S, Wang N, Pan D, Zhang H, Sun G. Effects of Copper Supplementation on Blood Lipid Level: a Systematic Review and a Meta-Analysis on Randomized Clinical Trials.. Biol Trace Elem Res. 2021. PMID 33030656. DOI 10.1007/s12011-020-02423-1. (abstract)
- Zhao H, Mei K, Hu Q, Wu Y, Xu Y, Qinling, Yu P, Deng Y, Zhu W, Yan Z, Liu X. Circulating copper levels and the risk of cardio-cerebrovascular diseases and cardiovascular and all-cause mortality: A systematic review and meta-analysis of longitudinal studies.. Environ Pollut. 2024. PMID 37852312. DOI 10.1016/j.envpol.2023.122711. (abstract)
- . EFSA: Overview on Tolerable Upper Intake Levels as derived by the SCF and the EFSA NDA Panel, version 11 (August 2025). . . (full-text)
- . MedlinePlus: Copper in diet (review date 1/21/2025). . . (full-text)
- . MedlinePlus: Wilson Disease (health topic). . . (full-text)
- . NHS: Vitamins and minerals - Others (copper section; page last reviewed 3 August 2020). . . (full-text)
- . NIH Office of Dietary Supplements: Copper fact sheet for health professionals. . . (not-read)
- . USDA FoodData Central: Cocoa, dry powder, unsweetened (FDC 169593, SR Legacy, April 2018). . . (full-text)
- . USDA FoodData Central: Seeds, sesame seeds, whole, dried (FDC 170150, SR Legacy, April 2018). . . (full-text)
- . USDA FoodData Central: Nuts, cashew nuts, raw (FDC 170162, SR Legacy, April 2018). . . (full-text)
- . USDA FoodData Central: Nuts, walnuts, english (FDC 170187, SR Legacy, April 2018). . . (full-text)
- . USDA FoodData Central: Seeds, pumpkin and squash seed kernels, dried (FDC 170556, SR Legacy, April 2018). . . (full-text)
- . USDA FoodData Central: Seeds, sunflower seed kernels, dried (FDC 170562, SR Legacy, April 2018). . . (full-text)
- . USDA FoodData Central: Lentils, mature seeds, cooked, boiled, without salt (FDC 172421, SR Legacy, April 2018). . . (full-text)
- . USDA FoodData Central: Chickpeas (garbanzo beans, bengal gram), mature seeds, cooked, boiled, without salt (FDC 173757, SR Legacy, April 2018). . . (full-text)
Where to buy
Check the label first. Whatever you buy, look for these:
- The amount of the active ingredient per serving, not just the front-label claim
- A third-party testing mark (USP, NSF or ConsumerLab)
- Other ingredients and allergens
- Ask a pharmacist about interactions with your medicines
Talk to a pharmacist or doctor before you start any supplement, especially if you take medicines. See the Safety tab for interactions.
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