Copper

Connective tissueEnergyIron metabolism

Essential trace mineral that's easy to overlook — until you've taken high-dose zinc for a few months and depleted it. Required for iron metabolism, collagen cross-linking, and energy production.

EvidenceModerate (general) / Strong (deficiency reversal)

Strong for reversing deficiency-related anemia, neutropenia, and neuropathy. Strong for preventing the zinc-induced copper deficiency that catches long-term high-dose zinc users. Less evidence for benefit in already-replete people. Effects: 4–8 weeks.

Copper is a cofactor for ~12 essential enzymes including cytochrome c oxidase (the final step of mitochondrial energy production), superoxide dismutase (antioxidant), lysyl oxidase (collagen and elastin cross-linking — what makes connective tissue strong), and ceruloplasmin (which loads iron onto transferrin). Most people get enough from food, but zinc supplementation — particularly at high doses for more than a few weeks — competitively depletes copper. Copper deficiency presents as anemia, low neutrophil count, easy bruising, and neurological symptoms. Just as importantly: too much copper is also a problem (Wilson disease, copper IUDs in some women), so the goal is balance, not maximisation.

Form
Copper bisglycinate — best-absorbed, gentlest. Copper sulfate — cheap, common, fine. Often included in multivitamins at 1–2 mg.
Dose
1–2 mg/day. Only supplement if running high-dose zinc, eating very plant-heavy / phytate-rich diets, or with documented deficiency. Total intake ceiling: 10 mg/day from all sources.
Timing
Anytime, with food. Separate from zinc by at least 2 hours (they compete for absorption).
Schedule
Daily, paired with zinc supplementation.
Side effects
Nausea, GI upset, metallic taste at high doses. Excess copper deposits in liver and brain over time (Wilson disease territory).
Interactions
Zinc (competitive absorption — most important interaction). Iron (high copper can elevate iron). Penicillamine, trientine (copper chelators — opposite direction).
Contraindications
Wilson disease (genetic copper accumulation — copper supplementation contraindicated). Hemochromatosis (copper increases iron levels). Cholestatic liver disease (copper accumulates).
Lab markers
Serum copper. Ceruloplasmin (the carrier protein — better functional marker). Copper-to-zinc ratio in serum is the most clinically useful — should be roughly 1:1, with high zinc:copper ratio (>1.5) suggesting copper deficiency.
Food sources
Beef liver (by far the richest source), oysters, dark chocolate, cashews, sesame seeds, sunflower seeds, lentils, mushrooms, shiitake mushrooms, spirulina. A single 3 oz serving of beef liver delivers roughly 14 mg copper.

Pairs with

Zinc — these two should always be balanced (10–15:1 zinc:copper ratio). Iron (copper is required to mobilise iron). Vitamin C can reduce copper absorption at high doses — separate timing.