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Zinc Side Effects & Safety

Evidence:Strong
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This content is for informational purposes only and does not constitute medical advice. Statements about dietary supplements have not been evaluated by the FDA and are not intended to diagnose, treat, cure, or prevent any disease. Individual results may vary — consult your healthcare provider before starting any supplement. Full disclaimer

Safety Profile

Overall safety rating: Generally Safe

Potential Side Effects

  • Nausea and stomach upset (most common, especially on empty stomach)
  • Metallic taste
  • Copper depletion with long-term use above 40 mg/day — supplement with 1-2 mg copper
  • Headache and dizziness at high doses
  • Diarrhea

Drug & Supplement Interactions

  • Competes with copper absorption — long-term zinc >40 mg/day requires copper co-supplementation
  • Reduces absorption of tetracycline and fluoroquinolone antibiotics — separate by 2 hours
  • Phytates in grains and legumes reduce zinc absorption
  • High-dose iron supplements may reduce zinc absorption
  • Thiazide diuretics increase urinary zinc excretion

Maximum Dose

Do not exceed: 40 mg/day (NIH Upper Tolerable Intake Level for adults); higher doses used short-term under medical supervision

Full Zinc Guide

References

  1. ReviewGupta M, Mahajan VK, Mehta KS, Chauhan PS. (2014). Zinc therapy in dermatology: a review. Dermatology Research and Practice. DOI PubMed
  2. Zhou H, Zhang Y, Tian T, Wang B, et al. (2025). Meta-analysis of the Relationship Between Zinc and Copper in Patients with Osteoarthritis.. Biological trace element research. DOI PubMed
  3. Meta-analysisHsu TJ, Hsieh RH, Huang CH, Chen CS, et al. (2024). Efficacy of Zinc Supplementation in the Management of Primary Dysmenorrhea: A Systematic Review and Meta-Analysis.. Nutrients. DOI PubMed
  4. Meta-analysisAli AA, Naqvi SK, Hasnain Z, Zubairi MBA, et al. (2024). Zinc supplementation for acute and persistent watery diarrhoea in children: A systematic review and meta-analysis.. Journal of global health. DOI PubMed
  5. Tabatabaeizadeh SA (2022). Zinc supplementation and COVID-19 mortality: a meta-analysis.. European journal of medical research. DOI PubMed
  6. Meta-analysisZupo R, Sila A, Castellana F, Bringiotti R, et al. (2022). Prevalence of Zinc Deficiency in Inflammatory Bowel Disease: A Systematic Review and Meta-Analysis.. Nutrients. DOI PubMed
  7. Banik S, Ghosh A (2022). Zinc status and coronary artery disease: A systematic review and meta-analysis.. Journal of trace elements in medicine and biology : organ of the Society for Minerals and Trace Elements (GMS). DOI PubMed
Show 1 more reference
  1. ReviewLansdown ABG, Mirastschijski U, Stubbs N, et al. (2007). Zinc in wound healing: theoretical, experimental, and clinical aspects. Wound Repair and Regeneration. DOI PubMed