Copper
A mineral that enzymes for energy production, iron metabolism, connective tissue and brain chemicals depend on. Shellfish, organ meats, nuts, seeds and chocolate are rich sources.
How much you need
The official Recommended Dietary Allowance for adults, per day:
| Age | Men | Women | Pregnancy | Breastfeeding |
|---|---|---|---|---|
| 19–50 years | 900 mcg | 900 mcg | 1,000 mcg | 1,300 mcg |
| 51–70 years | 900 mcg | 900 mcg | — | — |
| Over 70 | 900 mcg | 900 mcg | — | — |
People aged 18 fall in the official 14–18 group — 890 mcg a day, 1,000 mcg in pregnancy and 1,300 mcg when breastfeeding. Its upper limit is 8,000 mcg. Pregnancy and breastfeeding change what you need — confirm yours with your midwife, obstetrician or doctor.
Upper limit
| Age | Men | Women | Pregnancy | Breastfeeding |
|---|---|---|---|---|
| 19–50 years | 10,000 mcg | 10,000 mcg | 10,000 mcg | 10,000 mcg |
| 51–70 years | 10,000 mcg | 10,000 mcg | — | — |
| Over 70 | 10,000 mcg | 10,000 mcg | — | — |
The upper limit covers copper from food and supplements combined. It is the most that is unlikely to cause harm, not a target, and was set from the amounts linked to liver damage. It does not apply to people taking copper under medical supervision. One 3-ounce serving of pan-fried beef liver, the first food listed below, provides 12,400 mcg — more than the limit.
What it does
Copper is a cofactor for several enzymes involved in energy production, iron metabolism, activating neuropeptides, making connective tissue and making neurotransmitters [1]. It is also involved in forming blood vessels, brain development, pigmentation and immune function, and the body's defence against oxidative damage depends mainly on copper-containing enzymes [1]. The body holds only 50 to 120 mg, almost two-thirds of it in the skeleton and muscle [1].
Forms
Supplements contain cupric oxide, cupric sulfate, copper amino acid chelates, copper gluconate and other forms, in amounts from a few micrograms to 15 mg; no studies have compared how well the forms are absorbed [1].
Where it comes from
- Beef liver, pan fried3 ounces12,400 mcg
- Oysters, eastern, wild, cooked3 ounces4,850 mcg
- Baking chocolate, unsweetened1 ounce938 mcg
- Potatoes, cooked, flesh and skin1 medium potato675 mcg
- Mushrooms, shiitake, cooked½ cup650 mcg
How these five were chosen: The five foods with the most copper per serving in the NIH fact sheet's food table. Fortified foods are marked.
| Item | Percent of the adult daily amount (900 mcg) |
|---|---|
| Beef liver | 1378% |
| Oysters | 539% |
| Baking chocolate | 104% |
| Potato | 75% |
| Shiitake mushrooms | 72% |
Getting the most from it
How much copper the body absorbs depends strongly on how much is in the diet: about 75% when a diet provides only 400 mcg a day, and 12% at 7.5 mg a day [1]. Tap water and other drinks can also provide copper, in amounts that vary by source [1]. High intakes of zinc interfere with copper absorption [1].
In the United States
Typical U.S. diets meet or exceed the recommended amount: adults aged 20 and older average 1,400 mcg a day from food for men and 1,100 mcg for women [1]. In 2009–2012 data, 6% to 15% of adults who did not take a supplement containing copper had intakes below the average requirement, against 2.2% to 7.2% of those who did [1].
Who is most likely to run low
- People with celiac disease — in one study, 15% of 200 people with it were copper deficient [1]
- People with Menkes disease, a rare inherited disorder that sharply reduces copper absorption [1]
- People taking high doses of zinc supplements or overusing zinc-containing denture creams — zinc blocks copper absorption, even at about 60 mg a day for up to 10 weeks [1]
What deficiency looks like
Copper deficiency is uncommon [1]. From studies in animals and people, its effects include anemia, loss of pigmentation, high cholesterol, connective tissue disorders, osteoporosis and other bone defects, abnormal fat metabolism, loss of coordination and a higher risk of infection [1]. No biomarker reliably measures copper status, and it is not routinely assessed [1].
What the evidence supports, and what it doesn't
Established. Copper is essential for enzymes involved in energy production, iron metabolism and connective tissue, and deficiency causes anemia, bone defects and other problems [1]. In Menkes disease, copper injections started in the first weeks after birth can reduce the risk of death and improve development [1].
Not supported by trials. Alzheimer's disease: in a trial in 68 people aged 50 to 80 with mild Alzheimer's disease, 8 mg of copper a day for 12 months did not change cognition [1]. Heart disease: a few small studies in healthy adults found little evidence that copper supplements affect cardiovascular risk factors, and no trials have been done in people at higher risk [1].
Mixed. Observational studies of copper and heart disease disagree: in an Italian study, people eating the most copper had lower blood pressure and cholesterol, but in U.S. and German studies, those with the highest blood copper had higher rates of death from heart disease [1]. Studies of Alzheimer's disease conflict too — low copper has been found in the brains of people with the disease, but meta-analyses find higher blood copper [1].
Too much
Chronic exposure to high levels of copper can damage the liver and cause abdominal pain, cramps, nausea, diarrhea and vomiting [1]. Copper toxicity is rare in healthy people, but it has occurred from drinking water that stood in copper pipes and fixtures; the Environmental Protection Agency's recommended limit for public water is 1.3 mg per litre [1]. People with Wilson's disease, a rare inherited disorder that stops the body clearing copper, are at high risk of toxicity and can develop liver and nerve damage [1].
Medicines that interact
Copper is not known to have any clinically relevant interactions with medicines [1]. High-dose zinc supplements, though, can reduce copper absorption [1]. If you take medicines or zinc regularly, your doctor or pharmacist can tell you whether a supplement suits you.
References
- NIH Office of Dietary Supplements. Copper — Fact Sheet for Health Professionals. Updated 18 October 2022. ods.od.nih.gov
How we reviewed this page
Every value on this page comes from the NIH Office of Dietary Supplements — Copper, Health Professional Fact Sheet, which presents the official U.S. intake recommendations set by the National Academies. The source was last updated on October 18, 2022, and this page was checked against it on October 18, 2026. Numbered markers link to the source for each claim, so you can check the original rather than take our word for it.
Drafted with AI assistance, then edited and fact-checked by a human. No value is published on the strength of a model's recall.
Spotted an error? Tell us — corrections are logged publicly.
General information only. This is not medical advice.