What are the signs of copper deficiency?
Copper deficiency causes anaemia, loss of skin pigment, bone defects, unsteady movement and more infections.
Who is most likely to run low
Regular high doses of zinc from supplements, or excessive use of zinc-containing denture creams, can cause copper deficiency because zinc inhibits copper absorption.
What this means for you
Copper deficiency is rare from diet and not rare at all from supplements, which is an unusual shape for a nutrient problem.
It shows up as anaemia that iron does not fix, loss of skin pigment, bone thinning, unsteady movement and infections that keep coming back. The anaemia is what usually brings people in, and copper is rarely the first thing anyone tests.
Not for everyone. The most common cause in practice is high-dose zinc taken for months, or heavy use of zinc-containing denture cream. Zinc blocks copper absorption, and neither of those gets mentioned when someone lists their medicines, because neither feels like one.
Food covers copper without effort: shellfish, organ meat, nuts, seeds, whole grains and dark chocolate all carry it, and the requirement is 900 micrograms a day.
The other situations worth knowing are surgical. People who have had gastric bypass, and anyone with a condition that blocks absorption in the upper gut, can run low regardless of what they eat.
The honest version of this page is about how much of it reverses. In a review of 198 published cases of spinal cord damage from copper deficiency, stomach surgery and excess zinc were the two commonest causes, and after copper was replaced only a quarter of those people improved at all. One in twenty got back to where they started. That is the argument for finding it early rather than waiting to see whether the numbness settles.
What the case reports show
Established. Copper deficiency can damage the spinal cord, and the pooled case reports are sobering. Across 198 published cases, average age 53.6 and 64 per cent women, the two commonest causes were previous stomach surgery at 55 cases and too much zinc from denture cream at 39. Mean serum copper was 15.67 micrograms per decilitre against a normal range of 80 to 155. Even after copper was replaced, only 47 of those people reported any neurological improvement at all, about a quarter, and 10 returned to where they had started.
That last number is why this page exists. Most nutrient deficiencies forgive a late diagnosis. This one often does not. If you have had stomach surgery, or you use a zinc-containing denture cream every day, then numbness, unsteadiness or weakness in the legs is worth raising early rather than watching for a few months.
A copper result that means something else
Unsettled. A high copper reading is easy to over-read. Across 18 pregnancy cohorts, higher maternal blood copper went with preterm birth at an odds ratio of 1.30 and with pregnancies about a day and a half shorter. In one of those cohorts copper also tracked with the standard markers of inflammation and with malaria and HIV infection. Blood copper rises when the body is inflamed, so the likeliest reading is that it was marking illness rather than making it. One copper number out of context tells you less than it appears to.
If a deficiency has been confirmed and somebody is putting copper back, two figures frame the dose. Europe treats around 5 mg a day as the point where copper begins to accumulate and sets its safe level near 4.9 mg for a 70 kilogram adult, half the American ceiling of 10 mg. Choosing between them is the job of whoever is treating you.
Written from the evidence cards and the data on this page, then checked back against the sources. Bioma Learn has no human medical reviewer at this time and we say so rather than invent one. Information, not medical advice. How we verify.
Where to get it from food
- Sesame seeds, whole, dried — 5.88 mg per 1 cup (653% DV)
- Cashew nuts, dry roasted — 3.04 mg per 1 cup, halves and whole (338% DV)
- Cashew nuts, oil roasted — 2.64 mg per 1 cup, whole (293% DV)
- Mixed nuts, oil roasted, without peanuts — 2.58 mg per 1 cup (287% DV)
- Sunflower seed kernels, oil roasted — 2.44 mg per 1 cup (271% DV)
A symptom list is not a diagnosis. Every sign on this page has other causes that are more common than a nutrient deficiency, and the way to know is a blood test rather than a checklist.
Full guide: Copper: the mineral most people only hear about when zinc goes wrong
Source. effects of copper deficiency include anemia, hypopigmentation, hypercholesterolemia, connective tissue disorders, osteoporosis and other bone defects, abnormal lipid metabolism, ataxia, and increased risk of infection
— NIH Office of Dietary Supplements, Copper - Health Professional Fact Sheet, checked 2026-09-16. Evidence level E.
Source. People who regularly consume high doses of zinc from supplements or use excessive amounts of zinc-containing denture creams can develop copper deficiency because zinc can inhibit copper absorption.
— NIH Office of Dietary Supplements, Copper - Health Professional Fact Sheet, checked 2026-09-16. Evidence level E.