Answers › How much zinc is too much? The Australian upper limit
How much zinc is too much? The Australian upper limit
This page hasn't been reviewed by a pharmacist yet. It's general information, not medical advice.
Short answer
The Australian/NZ adult upper level of intake for zinc is 40 mg a day, counting food, water and supplements together. Long-term high zinc intake can cause copper deficiency, which is why many zinc products also contain copper. Add up zinc across every product (multis, immune blends, ZMA, lozenges) before adding more.
The number
The NHMRC Nutrient Reference Values set the adult upper level for zinc at 40 mg/day. [1]
Zinc and copper
NIH ODS notes chronic excessive zinc intake can cause zinc toxicity, including copper deficiency and neurological problems. [3] The Australian/NZ adult upper level for copper is 10 mg/day. [2]
Zinc and magnesium
Very high zinc doses (142 mg/day in one study) may interfere with magnesium absorption. [3]
Where totals creep up
Immune formulas, cold-and-flu lozenges, multivitamins and sleep or recovery blends often all contain zinc.
FAQ
Is 50 mg of zinc a day too much?
50 mg/day is above the 40 mg/day Australian/NZ adult upper level. Some people take more for short periods under medical advice; check with your GP or pharmacist.
Why do zinc supplements contain copper?
Because long-term high zinc intake can reduce copper absorption and cause copper deficiency.
Related
- Is it safe to take magnesium and zinc together?
- Can you take iron and calcium together?
- Every source the Checker uses
Sources
- NHMRC Nutrient Reference Values: Zinc
- NHMRC Nutrient Reference Values: Copper
- NIH ODS: Zinc fact sheet for health professionals
Sources checked 2026-10-18. Last updated 2026-10-18.