Safety

Is copper bisglycinate safe?

Q: Is copper bisglycinate safe?

Yes, for most adults at recommended doses. The tolerable upper intake level is 10 mg per day, well above the 1-2 mg in typical supplements. People with Wilson disease should not take copper supplements, and very high doses over long periods can cause adverse effects.

Last reviewed: May 2026

The short answer

Yes — for most adults at recommended doses. The Institute of Medicine has set the tolerable upper intake level for copper at 10 mg per day, well above the 1–2 mg supplied by typical copper bisglycinate supplements. The compound is consistently better tolerated than inorganic copper forms. Two important exceptions: people with Wilson disease should not take copper supplements, and very high doses (approaching or exceeding 10 mg/day) over long periods can produce adverse effects.

What the upper limit actually means

The 10 mg tolerable upper intake level was set by the Institute of Medicine based on protection against liver injury — the critical adverse effect at chronically excessive copper intake. The upper limit is not a cliff; it is the level at which adverse effects begin to become a meaningful concern for some adults over time. A 2 mg/day copper bisglycinate dose sits at 20% of the upper limit.

Reported side effects at typical doses

At 1–2 mg/day, side effects are uncommon. Some people report a mild metallic taste, particularly with sublingual or liquid copper formulations. GI symptoms — nausea, mild stomach upset — are far less common with copper bisglycinate than with copper sulfate. If you experience GI symptoms on copper bisglycinate, take it with a meal.

Reported side effects at high doses

At doses well above the upper limit (acute single doses in the tens of milligrams or chronic intake above 10 mg/day), copper can cause:

Nausea, vomiting, abdominal pain, diarrhea
Headache
Coppery aftertaste
Over chronic excessive intake: liver injury, the basis for the upper limit

Who should not take copper bisglycinate

People with Wilson disease, an inherited disorder of copper transport caused by ATP7B mutations. Copper accumulates pathologically in the liver and brain. Supplementation is contraindicated.
People with Menkes disease, a separate inherited disorder of copper transport, though this condition typically presents in infancy.
People taking certain chelating medications used for Wilson disease (e.g., penicillamine, trientine).
Anyone whose physician has specifically advised against copper supplementation.

Pregnancy and lactation

Copper requirements increase modestly during pregnancy (RDA 1,000 mcg/day) and lactation (RDA 1,300 mcg/day). Most prenatal multivitamins contain copper. Whether to add a separate copper bisglycinate supplement during pregnancy should be discussed with an obstetric provider.

Drug interactions to be aware of

Tetracycline and fluoroquinolone antibiotics — copper can chelate these drugs and reduce their absorption. Separate doses.
Penicillamine — used in Wilson disease and rheumatoid arthritis, this drug binds copper. Copper supplementation can interfere.
Proton pump inhibitors (omeprazole, esomeprazole) — long-term high-dose use reduces gastric acidity, which may affect mineral absorption broadly.

Sources

Institute of Medicine — Dietary Reference Intakes (Copper chapter) — ncbi.nlm.nih.gov
NIH Office of Dietary Supplements — Copper Fact Sheet for Health Professionals — ods.od.nih.gov