Evidence Level
Moderate
2 Clinical Trials
5 Documented Benefits
3/5 Evidence Score

Copper gluconate is a water-soluble copper salt of gluconic acid supplying roughly 14% elemental copper. It is the most common copper form in multivitamins and is a GRAS food fortificant, widely regarded as a reliable, well-absorbed oral reference form. Copper is an essential trace mineral and cofactor for enzymes in iron metabolism, antioxidant defense, connective-tissue cross-linking, and energy production. Copper gluconate is especially important to balance against high-dose zinc, which competes for absorption and can induce copper deficiency over time.

Studied Dose RDA 0.9 mg/day elemental copper; UL 10 mg/day. Supplements typically supply 1–2 mg; use about 1 mg copper per 15 mg supplemental zinc.
Active Compound Copper(II) gluconate, Cu(C6H11O7)2 — water-soluble organic salt and GRAS fortificant providing approximately 14% elemental copper by weight

Benefits

Supports healthy red blood cells

Copper-dependent ceruloplasmin helps load iron onto transferrin for transport to the bone marrow. Adequate copper status supports normal red blood cell formation, which is why balancing copper is important when iron metabolism is a concern.

Supports antioxidant defense

Copper is essential for copper-zinc superoxide dismutase, a key antioxidant enzyme in the cytoplasm that neutralizes superoxide radicals. Maintaining adequate copper status supports this part of the body's defense against oxidative stress.

Supports connective tissue and blood vessels

Copper activates lysyl oxidase, the enzyme that cross-links collagen and elastin in skin, bone, cartilage, and arterial walls. Adequate copper helps maintain the strength and elasticity of connective tissue and the cardiovascular structural matrix.

Balances high-dose zinc supplementation

Because zinc competes with copper for absorption, people taking higher-dose zinc benefit from added copper to prevent depletion. Copper gluconate is a well-absorbed, widely available form for maintaining proper zinc-to-copper balance.

Supports energy production

Copper is a core component of cytochrome c oxidase in the mitochondrial electron transport chain. Adequate copper status supports normal cellular respiration and ATP generation that power everyday energy needs.

Mechanism of action

1

Ceruloplasmin ferroxidase activity

Ceruloplasmin, a copper-containing protein, oxidizes ferrous iron to the ferric form that binds transferrin. This step is rate-limiting for iron export from stores, which is why copper deficiency can cause a functional iron-deficiency anemia despite normal iron.

2

Cu/Zn-SOD antioxidant catalysis

Copper in the active site of copper-zinc superoxide dismutase enables the conversion of superoxide radicals to hydrogen peroxide, a foundational antioxidant reaction in the cytoplasm that protects proteins, lipids, and DNA.

3

Cytochrome c oxidase electron transfer

Copper centers in cytochrome c oxidase (Complex IV) accept electrons and transfer them to molecular oxygen, completing the electron transport chain. Adequate copper is required for efficient mitochondrial ATP production.

4

Soluble salt absorption

Copper gluconate dissolves in the gut to release Cu2+, which is absorbed via copper transporter CTR1 in the small intestine. Fractional copper absorption is high at low intakes and decreases as intake rises, reflecting tight homeostatic control.

Clinical trials

1
Copper absorption regulated by dietary intake — stable isotope
PubMed

Controlled metabolic study using the stable isotope 65Cu to measure copper absorption and retention in young men at low, adequate, and high copper intakes.

11 young men (metabolic unit).

Copper absorption rose to about 56% on a low-copper diet and fell to roughly 12% on a high-copper diet, with adequate intake near 36%. This demonstrates strong homeostatic regulation of copper absorption and supports about 0.8 mg/day as adequate for young men.

2
Copper absorption at low dietary copper — stable isotope
PubMed

Stable-isotope (65Cu) metabolic study quantifying copper absorption, excretion, and retention in young men consuming a low-copper diet.

Young men consuming low dietary copper.

On low copper intake, fractional absorption increased and the body adjusted excretion to defend copper balance, confirming efficient adaptive uptake of dietary copper. These data underpin treating well-absorbed soluble salts like gluconate as reliable oral copper sources.

Side effects and drug interactions

Common Potential side effects

Generally well tolerated at supplemental doses within the 10 mg/day upper limit.
Nausea, vomiting, or abdominal pain can occur at high doses, especially on an empty stomach.
Chronic intake above the upper limit can stress the liver over time.
People with Wilson's disease must avoid supplemental copper due to dangerous copper accumulation.
Excessive copper without adequate zinc can disturb the copper-to-zinc balance.

Important Drug interactions

High-dose zinc (over about 40 mg/day) blocks copper absorption and can cause deficiency.
Copper chelators penicillamine and trientine for Wilson's disease are opposed by supplemental copper.
Antacids and proton pump inhibitors may reduce copper absorption; separate dosing.
High-dose vitamin C can modestly lower copper absorption when taken together.

Frequently asked questions about Copper Gluconate

What is copper gluconate?

Copper gluconate is copper bound to gluconic acid, a well-absorbed and gentle form commonly used in supplements and to balance zinc. It is one of the standard ways to supply small amounts of copper.

Why take copper gluconate?

Copper is often supplemented to prevent the copper deficiency that high-dose zinc can cause, and to support iron metabolism, connective tissue, and antioxidant enzymes. Copper gluconate is a common, well-tolerated form for this.

How much copper gluconate should I take?

Copper needs are small: the RDA is about 900 mcg per day. Supplements typically provide 1 to 2 mg of elemental copper, often paired with zinc. Avoid exceeding 10 mg per day from all sources.

Is copper gluconate safe?

At small supplemental amounts it is generally well tolerated. Because excess copper can cause nausea and, over time, liver stress, only supplement copper when needed (such as to balance zinc) and stay within recommended limits.

What is Copper Gluconate used for?

Copper Gluconate is researched primarily for Immune Support, Cardiovascular, and Antioxidant. Copper-dependent ceruloplasmin helps load iron onto transferrin for transport to the bone marrow. Adequate copper status supports normal red blood cell formation, which is why balancing copper is important when iron metabolism is a concern.

What is the recommended dosage of Copper Gluconate?

The clinically studied dose is RDA 0.9 mg/day elemental copper; UL 10 mg/day. Supplements typically supply 1–2 mg; use about 1 mg copper per 15 mg supplemental zinc. Always follow the product label and check with a healthcare provider for personal advice.

Is Copper Gluconate safe, and does it have side effects?

For most healthy adults, Copper Gluconate is well tolerated at studied doses. Reported effects can include: Generally well tolerated at supplemental doses within the 10 mg/day upper limit. Nausea, vomiting, or abdominal pain can occur at high doses, especially on an empty stomach. It may also interact with some medications. Copper Gluconate is not right for everyone, so check with a healthcare provider first if you are pregnant or breastfeeding, have a medical condition, or take prescription medication.

Does Copper Gluconate interact with any medications?

Possible interactions include: High-dose zinc (over about 40 mg/day) blocks copper absorption and can cause deficiency. Copper chelators penicillamine and trientine for Wilson's disease are opposed by supplemental copper. If you take prescription medication, check with a pharmacist or doctor before using it.

How strong is the scientific evidence for Copper Gluconate?

NutraSmarts rates the evidence for Copper Gluconate as Moderate (3 out of 5). It is backed by 2 clinical trials and 3 cited references summarized on this page. A higher rating reflects more, larger, and better-designed human studies.

References(3 citations)

Evidence ratings on NutraSmarts are based on the totality of human clinical research, with emphasis on randomized controlled trials, meta-analyses, and systematic reviews. The references below directly support claims made throughout this page.

  1. Turnlund JR, Keyes WR, Anderson HL, Acord LL. Copper absorption and retention in young men at three levels of dietary copper by use of the stable isotope 65Cu. Am J Clin Nutr. 1989;49(5):870-8. doi: 10.1093/ajcn/49.5.870.PubMedUsed to support: Demonstrates that copper absorption is high at low intakes and falls at high intakes, establishing efficient, regulated absorption of dietary copper relevant to soluble forms like gluconate.
  2. Turnlund JR, Keyes WR, Peiffer GL, Scott KC. Copper absorption, excretion, and retention by young men consuming low dietary copper determined by using the stable isotope 65Cu. Am J Clin Nutr. 1998;67(6):1219-25. doi: 10.1093/ajcn/67.6.1219.PubMedUsed to support: Shows adaptive increase in fractional copper absorption and adjusted excretion on low copper intake, supporting the reliability of well-absorbed oral copper.
  3. Baker DH. Cupric oxide should not be used as a copper supplement for either animals or humans. J Nutr. 1999;129(12):2278-9. doi: 10.1093/jn/129.12.2278.PubMedUsed to support: Contrasts well-absorbed soluble copper with poorly absorbed cupric oxide, supporting the use of soluble salts such as copper gluconate as effective oral copper sources.