Copper
Summary
Copper is an essential trace mineral found in liver, shellfish, nuts and chocolate. Adults need 900 mcg a day and the upper limit is 10 mg. Deficiency is uncommon; ODS lists celiac disease, Menkes disease and high-dose zinc as the main risks. A year of 8 mg/day did not change cognition in mild Alzheimer’s disease. ODS lists no known medicine interactions.
Key facts
- 900 mcg/day for adults; 1,000 mcg in pregnancy and 1,300 mcg during lactation[1]
- 10,000 mcg (10 mg) per day for adults[1]
- High zinc intakes block copper absorption; about 60 mg/day of zinc for up to 10 weeks lowered a copper-status marker, and overused zinc denture creams have caused copper deficiency[1]
- ODS lists three groups most likely to have inadequate copper status: people with celiac disease, people with Menkes disease (a rare inherited disorder that blocks copper absorption), and people taking high doses of zinc[1]
- Beef liver (12,400 mcg per 3 oz), oysters (4,850 mcg), unsweetened baking chocolate (938 mcg per oz) and cashews (629 mcg per oz)[1]
- 1 graded human outcome on this page
- October 11, 2026
How it works
EstablishedCopper is a cofactor for cuproenzymes involved in energy production, iron metabolism, neuropeptide activation, connective tissue synthesis and neurotransmitter synthesis.[1]
What the human research says
Human trials only, one row per outcome. The form column shows what each trial actually tested. Grades follow our evidence-grading policy.
| Outcome | Effect | Grade | Best evidence | PMID |
|---|---|---|---|---|
| Cognition in mild Alzheimer’s disease | No effect | No effect | Pilot RCT · n = 68 · 2008 Adults with mild Alzheimer’s disease Form: Copper(II) orotate dihydrate · Dose: 8 mg copper/day · Duration: 12 months No difference from placebo on ADAS-Cog or MMSE; copper was well tolerated and neither worsened nor slowed decline. | 18587525 (opens PubMed)Source [2] |
Forms
| Form | Elemental % | Absorption (human data) | GI tolerance | Studied for |
|---|---|---|---|---|
| Copper gluconate or bisglycinate | Varies | No head-to-head human absorption data in the sources cited here. | High intakes cause gastrointestinal symptoms; chronic excess can damage the liver.[1] | General supplements and multivitamins |
| Copper orotate | Varies | No head-to-head human absorption data in the sources cited here. | Well tolerated at 8 mg/day for 12 months in one trial.[2] | Alzheimer’s pilot trial |
Studied doses
Doses studied in human trials ranged from 2 mg of copper per day for 8 weeks and 3–6 mg per day in small trials in healthy adults to 8 mg per day for 12 months in mild Alzheimer’s disease, just under the 10 mg/day adult UL.[1][2]
Intake reference: Adult RDA: 900 mcg/day (19+), 1,000 mcg in pregnancy, 1,300 mcg in lactation. Tolerable Upper Intake Level: 10,000 mcg (10 mg)/day for adults.[1] ULs for children are lower (1,000 mcg at 1–3 years up to 8,000 mcg at 14–18 years); infants should get copper only from breast milk, formula and food. NIH ODS fact sheet (updated October 18, 2022).
Interactions
Published interactions only: each row cites a source. No row means none was found in our sources, not that a combination is safe.
Other supplements
- ZincNIH fact sheetHigh zinc intakes interfere with copper absorption and can cause copper deficiency.[1]
Who should be careful
- Wilson’s disease
- People with this inherited disorder accumulate copper and are at high risk of toxicity.[1]
- Intakes above the UL
- Chronic high copper can cause liver damage and stomach symptoms such as cramps, nausea and diarrhea.[1]
- People taking high-dose zinc
- Long-term high zinc can cause copper deficiency; a copper blood test shows status.[1]
Talk to your pharmacist or clinician before starting a supplement, especially if you take prescription medicines.
Food sources
| Food | Serving | Amount |
|---|---|---|
| Beef liver, pan fried | 3 ounces | 12.4 mg[1] |
| Oysters, cooked | 3 ounces | 4.85 mg[1] |
| Baking chocolate, unsweetened | 1 ounce | 0.938 mg[1] |
| Potato, with skin | 1 medium | 0.675 mg[1] |
| Cashews, dry roasted | 1 ounce | 0.629 mg[1] |
- Beef liver, pan fried12.4 mg
- Oysters, cooked4.9 mg
- Baking chocolate, unsweetened0.9 mg
- Potato, with skin0.7 mg
- Cashews, dry roasted0.6 mg
Frequently asked questions
How much copper do adults need?
900 mcg a day; more in pregnancy (1,000 mcg) and breastfeeding (1,300 mcg).[1]
Can zinc supplements cause copper deficiency?
Yes. High zinc intakes block copper absorption, and zinc overuse, including denture creams, has caused deficiency.[1]
How much copper is too much?
The adult upper limit is 10 mg a day; chronic excess can harm the liver.[1]
Does copper help memory?
A year of 8 mg/day did not change cognition in people with mild Alzheimer’s disease.[2]
Does copper interact with medicines?
ODS lists no known clinically relevant interactions with medications.[1]
Sources
- [1]Copper: Fact Sheet for Health Professionals. NIH Office of Dietary Supplements, 2022. fact-sheet
- [2]Intake of copper has no effect on cognition in patients with mild Alzheimer's disease: a pilot phase 2 clinical trial. J Neural Transm (Vienna), 2008. pilot-RCT
What changed
- New monograph. Every PMID checked against NCBI E-utilities (title, journal and year from the PubMed record); each evidence row written from its abstract; intake and safety facts from the cited fact sheets.
- Review: groups-at-risk line now matches the ODS fact sheet (celiac disease, Menkes disease, high-dose zinc); unsourced bariatric-surgery claim removed; dose range taken from the trials ODS describes.