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Supplement

Copper

Mineral · Copper, Cuprum

Copper is a trace element without which energy production, iron metabolism, connective tissue and nerves do not function. The body contains only 50 to 120 mg of it and regulates absorption very precisely. In the biohacking scene, copper appears mainly as a partner of zinc, and that is exactly where its most important practical role lies.

In short

Copper is essential and its functions are fully understood. A deficiency is rare but can be severe, with anemia and nerve damage up to the inability to walk, usually triggered by bowel diseases, stomach surgery or too much zinc. Anyone who eats normally in Germany takes in a median of 1.2 to 1.8 mg a day and is thus within the recommended range. For people without a deficiency, a benefit of copper supplements has not been shown; too much copper, on the other hand, accumulates. The EU upper limit is 5 mg a day; the BfR proposes at most 1 mg for food supplements.

What it is

Copper is a metal and an essential trace element for humans. An adult’s body contains a total of 50 to 120 mg, almost two thirds of it in bones and muscles. In the blood, copper is transported almost entirely bound to the protein ceruloplasmin, which carries over 95 percent of plasma copper.

The richest sources are liver and oysters, followed by shellfish, nuts, seeds, whole grains and cocoa. For adults, the nutrition societies of Germany, Austria and Switzerland give an estimated value of 1 to 1.5 mg a day, EFSA 1.6 mg for men and 1.3 mg for women. According to the German National Nutrition Survey, women in Germany take in a median of 1.2 to 1.5 mg and men 1.5 to 1.8 mg. EFSA notes that there is no indication of widespread copper deficiency in Europe.

How it works

Copper is a cofactor of a number of enzymes, the cuproenzymes. They work in energy production, in iron metabolism, in building connective tissue, in forming messengers in the nervous system and in protecting against oxidative damage. The best-known example of the last point is superoxide dismutase. Ceruloplasmin, in turn, plays a role in iron metabolism, and a copper deficiency can lead to anemia.

The EU has authorized all these functions as health claims. Accordingly, copper contributes to the maintenance of normal connective tissue, to normal energy metabolism, to the normal function of the nervous and immune systems, to normal pigmentation of skin and hair, to normal iron transport and to the protection of cells from oxidative stress. These statements describe what copper does in the body, not that additional copper achieves more of it when supply is good.

The zinc problem

The most important practical question is the interplay with zinc. In the gut, zinc stimulates the formation of metallothionein, a protein that binds copper and blocks its absorption. Even about 60 mg of zinc a day over up to 10 weeks lowered the copper-dependent superoxide dismutase in red blood cells in studies. Over months and years, this can turn into a severe deficiency. Cases of copper deficiency myelopathy, damage to the spinal cord with numbness and unsteady gait, have been described, for example in a 70-year-old woman after long-term use of a zinc-containing eye supplement and in a man who used zinc-containing adhesive cream for his dentures several times a day for 25 years. In both cases, the symptoms improved after stopping the zinc and giving copper.

What is well supported

It is well supported that copper is essential for life and what role it plays. It is equally clear who is at risk of deficiency: people with celiac disease or other absorption disorders, those who have had gastrointestinal surgery and anyone who takes in a lot of zinc over a longer period. In one study, 15 percent of 200 people with celiac disease on a gluten-free diet had a copper deficiency. A deficiency shows itself, among other things, through anemia, loss of pigment, bone loss and nerve damage, and if recognized in time it is often reversible.

It is also well supported that the body regulates absorption. In a metabolic study with 9 men, the proportion absorbed from the gut fell at high intake, and more copper was excreted again. This regulation has its limits, however, as the same study shows.

What the studies show

Copper in mild Alzheimer’s dementia 2008

In a double-blind study, 68 patients with mild Alzheimer’s dementia received 8 mg of copper as orotate or placebo daily for 12 months. Memory and thinking tests (ADAS-cog, MMSE) did not differ. In the cerebrospinal fluid, the Alzheimer’s marker Aβ42 fell by 10 percent under copper and by 30 percent under placebo; tau values remained the same. The authors see neither a harmful nor a beneficial effect on the course of the disease.

High copper intake over months 2004

9 young men first ate a controlled diet with 1.6 mg of copper a day for 18 days, then took an additional 7 mg for 129 days and finally received 7.8 mg for 18 days. Copper-dependent enzymes, copper in urine and hair and a marker of oxidative stress rose. Several immune values changed, and the antibody response after a flu vaccination was lower. The body retained more than 0.6 mg a day. What this means in the long term is unknown, according to the authors.

EFSA re-evaluation 2023

EFSA brought together the various limit values for copper, choosing storage in the liver as an early warning sign, because experience with Wilson’s disease shows that poisoning can set in suddenly after long accumulation. At 5 mg a day, no accumulation is to be expected. The tolerable intake is 0.07 mg per kilogram of body weight, and usual total intake does not exceed it in adolescents and adults.

Where the data stop

For people without a deficiency, it has not been shown that additional copper improves energy, the immune system, skin or blood vessels. For cardiovascular risk factors there is little evidence of an effect according to the US Office of Dietary Supplements; in Alzheimer’s, cognition remained unchanged at 8 mg a day. The antioxidant role is an enzyme function that is already covered with normal supply. A supplement provides no additional protection there, at least none has been demonstrated.

An ideal ratio of zinc to copper, as is often cited, could not be supported by any study either. All that is certain is that high amounts of zinc lower copper status. Finally, what the changes at high copper intake mean remains open: they were measured in only 9 men.

Status, approval and legal

Copper is an authorized mineral for food supplements and fortified foods. Binding EU maximum levels in food supplements do not yet exist. The BfR proposes at most 1 mg per daily dose, combined with the note that the product is not suitable for children and adolescents, and advises against fortifying other foods. The EU upper limit for total intake is 5 mg a day for adults and 4 mg for adolescents aged 15 and over, in the US 10 mg. Several health claims are authorized, for example on connective tissue, iron transport and the immune system. Copper is not relevant to doping.

Safety

Copper has a narrow range between requirement and excess. A normal diet already covers the requirement; any supplement comes on top. EFSA expects no accumulation at 5 mg a day; above that, copper can collect in the liver. Acutely, a lot of copper causes abdominal pain, cramps, nausea, vomiting and diarrhea. People with Wilson’s disease, a hereditary copper storage disease with liver and nerve damage, must not take copper supplements. Conversely, anyone who takes high-dose zinc over weeks and months or uses a lot of zinc-containing denture adhesive cream should think of their copper status and, in case of numbness, unsteady gait or anemia, have copper and ceruloplasmin measured by a physician. According to the BfR’s assessment, children and adolescents should not be given copper supplements.

BK-Score Thin human evidence

Human evidence5
Mechanism9
Safety data8
Hype gap3
Track record of use8

As an enzyme cofactor for superoxide dismutase, ceruloplasmin and other cuproenzymes, copper is fully understood, and deficiency with anemia and nerve damage is clearly described – but this deficiency is rare in healthy people without malabsorption, gastrointestinal surgery or zinc excess; median intake in Germany is 1.2 to 1.8 mg a day. For supplementation of people without a deficiency, the benefit has not been shown; an Alzheimer’s study with 68 patients and 8 mg daily over 12 months changed only an amyloid biomarker in the cerebrospinal fluid without a cognitive effect (Kessler 2008). The EU upper limit is 5 mg per day (SCF 2003; EFSA 2023: no retention at 5 mg), the US value 10 mg. In 9 men who took 7 mg in addition to their diet for 129 days and then 7.8 mg for 18 days, more than 0.6 mg per day was retained, copper status markers rose and immune values changed; the significance is unknown according to the authors (Turnlund 2004, 2005).

The score rates the state of knowledge, not the substance. “Safety data 9” means well studied – not harmless.
Subjective assessment by Biohacking Kompakt based on published scoring rules – not a scientific rating and not a medical recommendation. Rules and all ratings (German)

Frequently asked questions about copper

Do I need extra copper?

Usually not. In Germany, median intake from food is 1.2 to 1.8 mg a day and thus within the recommended range. Copper can make sense in absorption disorders, after gastrointestinal surgery or with persistently high zinc intake, ideally after a blood test.

Why does zinc lower copper levels?

In the gut, zinc stimulates a protein called metallothionein, which binds copper and prevents its absorption. Even about 60 mg of zinc a day over a few weeks lowered a copper-dependent enzyme. With high zinc intake over years, severe nerve damage due to copper deficiency has been described.

How much copper is too much?

The EU upper limit for adults is 5 mg a day from all sources, in the US 10 mg. For food supplements, the BfR proposes at most 1 mg per daily dose. In one study, copper already accumulated in the body at 7 mg in addition to food.

What are the symptoms of copper deficiency?

Typical are anemia and nerve damage with numbness, tingling and unsteady gait. Loss of pigment, bone loss and more frequent infections also occur. If recognized in time, the symptoms often regress.

Does copper help against Alzheimer’s?

In a placebo-controlled study with 68 patients, 8 mg of copper daily over 12 months did not change memory performance. An Alzheimer’s marker in the cerebrospinal fluid fell somewhat less. This does not show a clinical benefit.

Who must not take copper?

People with Wilson’s disease, a hereditary copper storage disease, must not take copper supplements. According to the BfR’s assessment, children and adolescents should not be given any either. In liver diseases, intake belongs in the hands of a physician.

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Information only, not medical advice and not a usage or dosage recommendation. Prescription-only and unapproved substances belong in the hands of a physician. Last updated: 2026-09-30.