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Epigallocatechin Gallate (EGCG) Side Effects & Safety

This content is for informational purposes only and does not constitute medical advice. Consult your healthcare provider before starting any supplement. Full disclaimer

Safety Profile

Overall safety rating: Safe with Caution

Potential Side Effects

  • Hepatotoxicity — the most serious concern; high-dose EGCG (especially fasted) has caused liver injury in multiple case reports and the USP has flagged this risk
  • GI symptoms (nausea, stomach upset, constipation)
  • Insomnia and anxiety if product contains caffeine
  • Iron absorption reduction — EGCG chelates non-heme iron; separate from iron-rich meals or iron supplements by 2+ hours
  • Headache at high doses

Drug & Supplement Interactions

  • Iron supplements and iron-rich foods — EGCG significantly reduces non-heme iron absorption; separate by 2+ hours
  • Warfarin — green tea contains vitamin K and may reduce warfarin efficacy
  • Nadolol and other beta-blockers — EGCG may reduce nadolol absorption and efficacy
  • Bortezomib (cancer drug) — EGCG directly inactivates this proteasome inhibitor; contraindicated
  • Hepatotoxic medications — avoid combining high-dose EGCG with other liver-stressing drugs

Maximum Dose

Do not exceed: 800mg EGCG/day (liver toxicity risk increases significantly above this level on an empty stomach)

Full Epigallocatechin Gallate (EGCG) Guide

References

  1. (). The anti-obesity effects of green tea in human intervention and basic molecular studies. European Journal of Clinical Nutrition. DOI
  2. (). Green tea consumption and mortality due to cardiovascular disease, cancer, and all causes in Japan. JAMA. DOI
  3. (). Hepatotoxicity of green tea: an update. Archives of Toxicology. DOI