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Other common name(s): none

Scientific/medical name(s): Cu, cupric oxide, copper sulfate, copper gluconate, copper picolinate, cupric acetate, alkaline copper carbonate


Copper is a required nutrient. It is found naturally in foods such as shellfish, beef liver, whole grains, beans, peas, nuts, potatoes, green vegetables, and chocolate. Copper helps regulate blood pressure and heart rate and is needed to absorb iron from the gut. It is used to make many important compounds in the body.


Some laboratory and animal studies have found that copper has antioxidant properties and may have some anti-cancer effects. Other studies have found that high copper levels in the blood were linked with cancer and other diseases. Newer studies are looking at whether depriving the body of copper can help stop cancer growth. More extensive human studies are needed to learn what role copper may play in preventing or treating cancer.

How is it promoted for use?

Scientists know, based on many studies, that copper is a trace element needed to support nerve function and help the body use iron. It is important to a number of enzyme systems, and helps produce energy and skin color (melanin).

There are also claims that copper helps healing, helps to expel toxins from the body, prevents thyroid problems, promotes healthy skin and hair, and helps prevent heart problems. A few maintain that it can cure slipped discs, aneurysms, and even hemorrhoids.

On the other hand, some claim that copper promotes cancer growth. Proponents of this theory recommend a diet low in copper and the use of chelating agents that bind to copper and help remove it from the body (see our document, Chelation Therapy).

What does it involve?

Copper supplements are available in pill or capsule form. Copper is often added to vitamin and mineral supplements. But most people are able to get enough copper in their bodies by eating balanced meals. Fruits and vegetables can provide up to 30% of a person's total copper intake. Copper is often present in drinking water, mainly from copper pipes that leach it into the water as it flows through.

The minimum recommended dietary allowance (RDA) for copper is 0.9 milligrams per day for most adults, 1 milligram for pregnant women, and 1.3 milligrams for women who are breast-feeding. The RDA is enough to meet the needs of most people in these groups.

Some people may not get enough copper from foods, especially if they take zinc supplements, which can partly block copper absorption. Large doses of vitamin C supplements can also block copper uptake. People who take zinc supplements or large doses of vitamin C may need to take extra copper to absorb enough. Those with malabsorption diseases or malnutrition may also need extra copper.

What is the history behind it?

While research into the antioxidant properties of copper is quite recent, healing properties have long been attributed to copper in folk medicine. Some people wear copper bracelets, for example, because they believe it helps with arthritis. Today, many multivitamins and other herbal and mineral supplements include copper.

What is the evidence?

Copper is a trace mineral that is needed for many important body processes. Animal studies have shown that copper is useful in maintaining antioxidant defenses. Antioxidants block the actions of free radicals, which are activated oxygen molecules that can damage cells. While the role of copper in the cancer process is still unclear, copper complexes have been shown to have anti-cancer properties in laboratory studies.

Other laboratory and animal studies suggest that high copper levels may be linked to liver cancer and brain tumors. More recently, many studies have shown that patients' blood copper levels are higher in several types of cancer and other diseases. To add to the confusion, blood tests can show high copper levels even when there is little copper in the tissues. These high copper levels may be due to injury, disease, or inflammation. Because copper levels in the blood do not always reflect nutritional status, it's hard to design or find good studies of copper.

Copper is needed to form new blood vessels, and because cancer needs new blood vessels in order to grow, some researchers are lowering copper levels to see if it will help slow tumor growth. In effect the researchers are trying to use low copper levels to starve the tumor of nutrients by keeping it from building new blood vessels (anti-angiogenesis). One group of researchers looked at whether a copper-lowering drug, tetrathiomolybdate (or TM), could help patients with advanced kidney cancer. Some patients' cancer stopped growing during the 6-month treatment period. A few people had low white blood counts during treatment, requiring that treatment be stopped until they recovered. This was a small study, and further research is needed to find out whether copper can help more people with advanced cancer.

More study of TM and a related drug (ATN-224) is taking place to find out if lower copper levels can help other anti-cancer treatments work better. Though most of the studies so far have been in the lab, early clinical trials in people with solid tumor cancers look promising. People taking copper-lowering drugs with cancer treatment have had problems with anemia, tiredness, and low white blood cell counts.

Another study noted high copper levels in the blood of people who died from heart disease. It is not known whether the laboratory tests accurately reflected copper levels in the body tissue or exactly what caused the high levels. In contrast, a recent study gave copper supplements to healthy women with no signs of copper deficiency. Their cholesterol and triglyceride levels improved, as did some other markers of heart disease risk. This small study did not look at actual heart disease, however. Further research is required to determine whether copper can affect heart disease risk.

Many people wear copper bracelets for their arthritis, and some people report improvements in their arthritis symptoms. However, available scientific evidence does not support claims that the bracelets are effective. A gel form of copper salicylate (an aspirin-copper compound) was no better for pain relief than sham gel, although the copper gel produced more rashes.

One lab study showed that the white blood cells of men who had been on a low-copper diet were less effective attacking germs than they were when the same men were getting enough copper. An older study in a group of children recovering from malnutrition showed that those who got copper supplements had fewer lung infections than those who got sham supplements. While these studies suggest that severe copper deficiency results in poorer immune function, further studies are needed to find out what effect, if any, milder deficiency might have.

There is some evidence that trace metals, including copper, iron and zinc, may have a role in forming the brain plaques associated with Alzheimer's disease. There is not enough evidence to define the role of copper in this process.

At this time, it is hard to say how each nutrient or nutrient combination affects a person's risk of cancer. On the other hand, studies looking at large groups of people have shown that those whose diets are high in vegetables and low in animal fat, meat, and/or calories have lower risks for some of the most common types of cancer.

Until more is known about this, the American Cancer Society recommends eating a variety of healthful foods -- with most of them coming from plant sources -- rather than relying on supplements. In certain situations, supplements may help some people, such as pregnant women, women of childbearing age, and people with restricted food intakes. If a supplement is taken, the best choice for most people is a balanced multivitamin/mineral supplement that contains no more than 100% of the "Daily Value" of most nutrients.

Are there any possible problems or complications?

This product is sold as a dietary supplement in the United States. Unlike companies that produce drugs (which must be tested before being sold), the companies that make supplements are not required to prove to the Food and Drug Administration that their supplements are safe or effective, as long as they don't claim the supplements can prevent, treat, or cure any specific disease.
Some such products may not contain the amount of the herb or substance that is on the label, and some may include other substances (contaminants). Actual amounts per dose may vary between brands or even between different batches of the same brand. In 2007, the FDA wrote new rules to improve the quality of manufacturing for dietary supplements and the proper listing of supplement ingredients. But these rules do not address the safety of the ingredients or their effects on health.
Most such supplements have not been tested to find out if they interact with medicines, foods, or other herbs and supplements. Even though some reports of interactions and harmful effects may be published, full studies of interactions and effects are not often available. Because of these limitations, any information on ill effects and interactions below should be considered incomplete.

Adults are advised not to take more than 10 milligrams of copper per day due to the risk of liver damage. The recommended maximum dosage is lower for children, depending on age.

Copper toxicity is rare, and copper supplements are considered safe when taken in recommended amounts. Copper overdoses can cause serious problems such as liver damage, kidney failure, coma, and death. Early symptoms of overdose may include nausea, vomiting, diarrhea, abdominal pain, problems with coordination or movement, and sleepiness. There may also be behavioral problems, such as trouble concentrating or emotional disturbances.

People with Wilson's disease (a genetic disorder that allows copper to build up in the body) should not take copper supplements or multivitamins that contain copper. Diabetics should also avoid these supplements because copper can affect blood sugar levels.

Problems may also happen when a person has too little copper. Copper is required for iron to be absorbed into the body and is necessary for babies to develop normally. Osteoporosis (thinning bones) can develop in infants and adults with too little copper. In adults, low copper levels can result in anemia and low white blood cell counts. Low copper levels in adults have been reported to cause muscle spasms in the legs and trouble walking.

Copper supplements can interfere with some medicines. Talk with your doctor or pharmacist about all medicines, herbs, and supplements that you are taking.

Relying on this type of treatment alone and avoiding or delaying conventional medical care for cancer may have serious health consequences.

Additional resources

More information from your American Cancer Society

The following information on complementary and alternative therapies may also be helpful to you. These materials may be found on our Web site (www.cancer.org) or ordered from our toll-free number (1-800-227-2345).

Dietary Supplements: What Is Safe?

The ACS Operational Statement on Complementary and Alternative Methods of Cancer Management

Complementary and Alternative Methods and Cancer

Placebo Effect

Learning About New Ways to Treat Cancer

Learning About New Ways to Prevent Cancer


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Note: This information may not cover all possible claims, uses, actions, precautions, side effects or interactions. It is not intended as medical advice, and should not be relied upon as a substitute for consultation with your doctor, who is familiar with your medical situation.

Last Medical Review: 03/07/2011
Last Revised: 03/07/2011