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8 Health Benefits of Copper & 7 Ways Excess Copper is Bad

Written by Maja Stanojevic, MD | Reviewed by Nattha Wannissorn, PhD (Molecular Genetics) | Last updated:
Medically reviewed by
Jonathan Ritter, PharmD, PhD (Pharmacology) | Written by Maja Stanojevic, MD | Reviewed by Nattha Wannissorn, PhD (Molecular Genetics) | Last updated:

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Copper is an important trace mineral. We need it for normal growth, bone strength, immune function, and cardiovascular health. However, too much of it can be toxic. Read this post to learn more about the health benefits of copper, harmful effects of copper overload, and ways to change your copper absorption.

How is Copper Used in the Body?

Copper is an essential trace mineral in the human body. It is required for growth, bone strength, immune function, as well as heart function, and brain development [1, 2].

Copper is an integral part (cofactor) of a group of enzymes called cuproenzymes, which are important for [3]:

Due to its potent antimicrobial properties, copper is also used as a biocide in agriculture, wood preservation, paints, and in hospitals [8, 9, 10, 11].

Health Benefits

1) Proper Immune Function

Copper plays an important role in white blood cell growth and function.

One month of copper supplementation in infants with deficiency significantly increased the ability of white blood cells to engulf pathogens.

Adequate copper supplementation rapidly restores the number and function of T lymphocytes in copper-deficient rats [12].

Also, copper supplementation increased secretion of cytokine IL-2 but decreased secretion of the inflammation-causing cytokine TNF-alpha [13].

In the 19th century, workers exposed to copper salts did not develop cholera during the cholera epidemics [14].

2) Bone Health

Copper plays an important role in bone formation [15].

Copper is a cofactor for enzyme lysyl oxidase required for the formation of strong bones [16, 17].

A study in perimenopausal women showed that 3 mg/day of copper supplementation for two years slowed down the loss of bone mineral density that typically accompanies menopause [18].

Additionally, a study in postmenopausal women found that taking a combination of supplemental calcium and trace minerals, including copper, might slow down bone loss [19].

Copper supplementation reversed bone abnormalities in copper-deficient infants [20].

In copper-deficient elderly patients, copper supplementation improved overall copper status and markers of bone resorption and formation [21].

3) Heart and Blood Vessels Health

Copper is essential for the strength and integrity of the heart and blood vessels. Copper supplementation improves altered heart function and promotes the regression of heart enlargement caused by copper deficiency [22, 23, 24, 25, 26, 27].

Copper supplementation and dietary copper may decrease the chances of atherosclerosis, heart attack, and stroke [28].

A study in healthy young women found that supplementation with 6mg of copper for 4 weeks led to a 30% reduction in plasminogen activator inhibitor-1 (PAI-1), thus decreasing the risk for atherosclerosis [29, 30].

In rats, copper supplementation decreased blood levels of total cholesterol, triglycerides, and “bad” LDL–cholesterol while slightly increasing “good” HDL-cholesterol. This was because copper increased the body’s own antioxidant defenses, by increasing total antioxidant levels and glutathione peroxidase enzyme activity [31].

A clinical study confirmed this finding [32], which suggests that copper supplementation can be used in the treatment of patients with high triglycerides and cholesterol.

4) May Prevent Neurodegenerative Diseases

Copper is important for the activity of enzymes that are crucial for brain development and function [33].

Studies showed potential beneficial roles of copper in treating rather than causing Alzheimer’s disease [34].

Copper prevents the formation of plaques in the brains of Alzheimer’s disease patients [35, 36].

Long-term copper treatment decreases cerebral spinal fluid levels of Aβ42, a diagnostic marker for Alzheimer’s disease [37].

Copper sulfate prevents motor deficits in a Parkinson’s disease model in mice [38].

5) May Protect Against Cancer

Copper increases the production of the tumor-suppressor protein p53, which inhibits the growth of tumors in the body [39, 40].

Treatment with copper decreased tumor growth and increased survival rate in mice with cancer [41].

Copper supplementation significantly increased the sensitivity of oral cancer cells to curcumin [42].

6) Improves the Well-Being of the Skin

Copper increases the production of collagen (which provides strength and structure) and elastin (which provides skin elasticity and resilience) [43, 44].

Copper oxide, due to its antimicrobial and antifungal properties, can be used for treating athlete’s foot infections when used as copper-impregnated socks [45].

Copper-impregnated socks may also be used to prevent skin infection, cuts, and wounds that often lead to hard to treat ulcers in diabetic patients [46].

Sleeping on copper oxide-containing pillowcases can reduce fine wrinkles and overall improvement of skin appearance [47, 48].

Cooper used in wound dressings can help enhance wound healing by increasing skin regeneration and the formation of new blood vessels [49]. In addition, the copper in wound dressings also has potent antimicrobial properties, which can reduce the risk of wound contamination [8].

These copper oxide products are non-irritating and safe to use both on intact and damaged skin [50].

7) May Heal Stomach Ulcers

Studies show that copper complexes (copper aspirinate, copper tryptophanate) prevent or even heal stomach ulcers associated with aspirin therapy [51].

These copper complexes promote normal wound healing while at the same time enhance the anti-inflammatory effects of nonsteroidal anti-inflammatory drugs such as aspirin and ibuprofen [52, 53].

8) May Reduce Anxiety and Depression During Pregnancy

Copper supplementation during pregnancy decreases risks of depression and anxiety [54].

The Bad: Copper Overload

Causes of Copper Excess

  • Inflammation [55]
  • Infection (tuberculosis, leprosy, viral hepatitis, pneumonia, and chickenpox) [56, 57]
  • Hematologic diseases (iron deficiency anemia, aplastic and pernicious anemia, sickle cell anemia, and beta-thalassemia) [58, 59]
  • Diabetes [60]
  • Heart and blood vessel disease [61, 62]
  • Malignant diseases (acute and chronic leukemia, Hodgkin’s disease, multiple myeloma, breast and lung cancer) [63, 64, 65, 66]
  • Liver disease (cirrhosis, hepatitis, obstruction to bile flow) [67, 68]
  • Contraception (oral contraceptive use, copper intrauterine device) [69, 70]
  • Pregnancy [71]
  • Drugs (water pills) [72]

Signs of Copper Overload

Acute Toxicity

Copper toxicity occurs with the ingestion of copper compounds usually with suicidal intent, or with accidental consumption of copper-contaminated foods, or water.

Ingestion of more than 1 g of copper can cause copper toxicity. However, this is only a rough threshold for toxicity and depends on individual factors [73].

Symptoms include stomach ache, nausea, vomiting, diarrhea, dizziness, and muscle pain. More serious signs of copper toxicity include severe liver and kidney damage, hemolytic anemia, massive gut bleeding, and even death [74, 75, 73].

Chronic Toxicity

The long-term copper toxicity is not frequent in individuals who do not have inherited disorders of copper metabolism.

Chronic ingestion of copper supplements taken in a dose of 30 – 60 mg/day during 3 years caused severe liver disease [76].

Negative Health Effects of Copper Excess

1) Causes Oxidative Damage

Excess free copper is toxic [77].

Increased copper levels may increase the production of free radicals which results in cell and tissue damage [78, 79].

2) Associated with Alzheimer’s Disease

There has been an ongoing debate about whether copper is a causative or a preventive agent of Alzheimer‘s disease (AD) [80].

Copper is thought to contribute to AD since alterations in copper levels tend to precede symptoms of AD in some, but not all patients [81].

Generally, subjects with AD have higher free blood and/or brain copper concentrations [82, 83, 84, 85].

Copper seems to be associated with worsening of symptoms and may have a causative role, suggesting that the elderly may benefit from reducing copper intake from food and supplements [86, 87, 88].

A study has shown that copper is a component of the amyloid-beta plaques which are found in the brains of people with AD [77].

On the other hand, studies also demonstrate potential beneficial roles of copper in treating rather than causing AD [35, 34, 36, 37].

3) May Increase Risk of Parkinson’s Disease

Occupational studies showed that long-term exposure to copper and manganese increases the risk of Parkinson’s disease [89].

Free copper has the ability to produce free radicals, and increase Lewy body formation, the hallmark of Parkinson’s disease [90].

4) Alters Immune System Function

High intakes of copper significantly reduced the number of neutrophils, levels of IL-2, and levels of antibody level against the Beijing strain of influenza.

Excess blood copper and ceruloplasmin may suppress immune function, especially in older organisms.

5) Increases Risk of Heart and Blood Vessel Disease

A study found that increased copper and ceruloplasmin levels are associated with an increased risk of heart attack and cardiovascular disease [61, 62].

Copper levels in the blood and in the blood vessel wall are elevated in individuals with atherosclerosis.

In addition, copper levels increase with the severity of atherosclerosis [91, 92].

6) May Be Associated with Diabetes

Blood copper levels are significantly increased in type 1 and 2 diabetics [93].

Copper is involved in the production of free radicals that play an important role in the development of diabetic complications [94, 95].

7) May Be Associated with Depression

Patients with depression have higher levels of blood copper, even after effective antidepressant treatment. This suggests that blood copper levels may be a “trait marker” for depression [96, 97].

Elevated copper levels are also associated with depression in shift nurses and post-partum depression [98, 99].


Food Sources

Copper-rich food include [100, 101, 102]:

  • Liver (especially calf, lamb, beef)
  • Seafood (oysters, squid, lobster, crab)
  • Fruit and vegetables (dark leafy vegetables, potatoes, mushrooms, avocados, dried fruit)
  • Seeds (sesame, sunflower, pumpkin)
  • Nuts (cashew, hazelnuts, Brazil nuts, walnuts),
  • Beans (chickpeas, soybeans, adzuki),
  • Goat cheese
  • Soy products (tofu, tempeh, soy milk, soy powder)
  • Chocolate, cocoa
  • Wheat bran cereals and whole-grain products

Copper may also be obtained from drinking water from copper pipes. The U.S. Environmental Protection Agency allows up to 1.3 mg/L of copper in human drinking water [103, 104].


A number of copper supplements are available in the form of copper oxide, copper chloride, copper gluconate, copper sulfate, and copper amino acid chelates [105].

Although copper is essential to health, supplementation is unnecessary for most healthy individuals [106].

Copper supplements are indicated for the prevention and treatment of copper deficiency and copper deficiency anemia [107].

Copper supplementation should not be used in individuals with genetic disorders affecting copper metabolism:

  • Wilson’s disease [108]
  • Idiopathic copper toxicosis [109]
  • Childhood cirrhosis syndromes (Indian childhood cirrhosis, idiopathic copper toxicosis) [110, 109]


The Recommended Dietary Allowance (RDA) for copper [111]:

  • Children 0.3 – 0.9 mg/day (depending on age)
  • Adults 0.9 mg/day
  • Pregnancy and lactation 1 – 1.3 mg/day

The average intake of copper from food in the United States is approximately 1.0 to 1.6 mg/day for adult men and women.

The Tolerable Upper Intake Level, the highest level of daily nutrient intake that is likely to pose no risk of adverse health effects for almost all individuals, for adults is 10 mg/day [111].


Copper is an essential but also potentially toxic element [79, 112].

The human body is somewhat protected from copper deficiency and toxicity because the body can balance copper absorption with physiological needs and elimination.

Copper absorption becomes more efficient with reduced dietary copper intake, and vice versa [113]. When measured in humans, copper absorption was only 12% when the intake was 7.5 mg/d, but it increased to 36% when the intake was 1.7 mg/d [114].

The balance of copper in the body is also maintained by excretion. The excretion is low when dietary copper is low, whereas excretion increases as dietary copper increases [115].


Absorbed copper binds to protein albumin and amino acids (histidine), and it is transported via the portal vein to the liver [116].

In the liver, it is either incorporated into the proteins and enzymes or secreted into the bile [117].

Most of it (70 – 95%) is bound to ceruloplasmin, the main carrier in the blood, while the remaining 10% is bound to albumin or carried as amino acid-bound copper, and transported into various tissues [79, 118].

Organs with high content include liver, brain, kidneys, and heart [119].


Approximately 80 – 90% of dietary copper is excreted in the feces. The amount excreted in urine, hair, and sweat is negligible [120].


Dietary copper is partially absorbed in the stomach. However, the largest portion is absorbed in the beginning region of the small intestine [121].

Absorption of copper ranges from 15 – 97%, depending on several factors including age and sex of the individual, levels of dietary copper, its forms, and composition of the diet.

Copper salts, including copper gluconate, copper acetate, or copper sulfate, are more easily absorbed than copper oxides [122, 123].

Ways to Increase Absorption


High dietary protein intake has been shown to increase absorption, although individual amino acids can either increase or decrease absorption [124].

L-histidine and L-cysteine can reduce copper absorption while glycine, L-tryptophan, and L-methionine increase it [125, 126].

Phytic Acid

Phytic acid, found in nuts, seeds, and beans, enhances copper absorption by its ability to bind other dietary components that decrease absorption in the gut [123].

Ways to Decrease Absorption

Zinc supplementation increases metallothioneins, proteins which bind copper and prevent its absorption.

Copper deficiency has been reported in humans using up to 600 mg elemental zinc daily or excessive usage of zinc-based dental adhesives [127, 128, 129].


Copper increases gut absorption and utilization of iron, while iron may inhibit copper absorption [130, 131].

Adequate copper blood levels are necessary for normal iron metabolism and red blood cell formation [132].


Copper absorption may be influenced by the type of carbohydrate consumed.

Rats fed a diet containing fructose developed more severe signs of copper deficiency than did rats fed a diet containing either glucose or starch [133].

Dietary Fibers

Dietary fiber may decrease copper absorption [134].

Vitamin C

Vitamin C decreases the absorption of copper in the gut but increases uptake in the cells [135].

High Molybdenum

Excessive dietary intake of molybdenum may form complexes with copper and can induce deficiency [136].


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Part 2: Negative Effects of Copper Deficiency and Blood Tests for Copper Levels

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