Minerals · 3 min read ·

Copper: an inconspicuous mineral that zinc can push out

Enzymes need copper to produce energy, and so do nerves and connective tissue. A deficiency is rare — most often it is caused by high doses of zinc over a long time.

63.546 Cu 29 Zn 30

In a nutshell

1What it does and how much you need

Copper is part of many enzymes that move electrons when producing energy, make nerve messengers and strengthen collagen and elastin. A deficiency causes anaemia that iron does not fix, nerve damage and slack skin.1

EFSA recommendation 1.6 / 1.3 mg EFSA set the adequate intake of copper at 1.6 mg a day for men and 1.3 mg for women; 0.2 mg more in pregnancy and breastfeeding.1
Upper level 5 mg The upper level for adults is 5 mg of copper a day.2 In 2023 EFSA confirmed that copper does not build up in the body at an intake of 5 mg a day and set an acceptable daily intake of 0.07 mg per kilogram of body weight.3

2Where to find it

Data 9.8 mg A hundred grams of beef liver contain 9.8 mg of copper — twice the upper level. Sesame (4.1 mg), unsweetened cocoa (3.8 mg), cashews (2.2 mg) and dark chocolate (1.8 mg) also have a lot. People in Europe get most of their copper from cereals and cereal products.1,4

3Forms and absorption

EFSA recommendation 50% About 50% of copper from food is absorbed. When the body is low on copper, absorption increases; the liver excretes any excess into the bile.1

In the EU, supplements may contain copper as carbonate, citrate, gluconate, sulphate, L-aspartate or bisglycinate, as a lysine complex or as copper oxide.5

Weak evidence — a review oxide A review of the research advises against using copper oxide as a source of copper — for animals as well as for people.6

4Zinc takes its place

Weak evidence — case reports 37 cases A review of 37 reported cases: high zinc intakes (about 50 to over 1,500 mg a day) over a long time from supplements, denture creams or swallowed coins caused copper deficiency. Almost all had anaemia and often low white blood cells. After stopping zinc and adding copper, the blood usually recovered within weeks to months; nerves more slowly and sometimes not fully.7
Weak evidence — case reports 4 people Four people with copper deficiency and nerve problems had used large amounts of denture creams for a long time; the creams contained 17,000–34,000 µg of zinc per gram.8

What to take from this

Sources

Written on , based on studies available at that date. Newer research may change the conclusions.

  1. EFSA NDA Panel (2015). Scientific Opinion on Dietary Reference Values for copper. EFSA Journal 13:4253. doi.org/10.2903/j.efsa.2015.4253
  2. EFSA (2025). Overview on Tolerable Upper Intake Levels as derived by the Scientific Committee on Food (SCF) and the EFSA Panel on Nutrition (version 11). efsa.europa.eu
  3. EFSA Scientific Committee (2023). Re-evaluation of the existing health-based guidance values for copper and exposure assessment from all sources. EFSA Journal 21:e07728. doi.org/10.2903/j.efsa.2023.7728
  4. USDA ARS (2018). FoodData Central — SR Legacy, copper per 100 g: beef liver, raw 9.8 mg (FDC 169451), sesame seeds 4.1 mg (FDC 170150), cocoa powder, unsweetened 3.8 mg (FDC 169593), cashews 2.2 mg (FDC 170162), dark chocolate 70–85% 1.8 mg (FDC 170273). fdc.nal.usda.gov
  5. Directive 2002/46/EC on food supplements, Annex II — forms of vitamins and minerals permitted in supplements (consolidated version 26 Nov 2025). eur-lex.europa.eu
  6. Baker D. H. (1999). Cupric oxide should not be used as a copper supplement for either animals or humans. J Nutr 129:2278–2279. doi.org/10.1093/jn/129.12.2278
  7. Dutta A. et al. (2026). Zinc-induced hematologic toxicities: a systematic review of descriptive studies. Biol Trace Elem Res 204:6628–6642. doi.org/10.1007/s12011-026-05136-z
  8. Nations S. P. et al. (2008). Denture cream: an unusual source of excess zinc, leading to hypocupremia and neurologic disease. Neurology 71:639–643. doi.org/10.1212/01.wnl.0000312375.79881.94

This is general information and does not replace a doctor. Food supplements are not medicines; buy them from trusted sellers and talk to a doctor if you are ill or take medicines.