EGCG (epigallocatechin gallate)
Primary bioactive catechin of green tea. Inhibits fatty acid synthase, activates AMPK, and has antioxidant and anti-tumour properties in preclinical studies. Hepatotoxicity at high doses documented. EFSA scientific opinion: tolerable upper intake 800mg/day EGCG.
How it works (mechanism of action)
Acts on cellular signalling pathways relevant to the documented clinical indications. Contains bioactive compounds with enzyme-modulating, receptor-binding, or antioxidant properties studied in peer-reviewed literature.
Evidence grades: A=Strong RCT evidence · B=Good clinical trials · C=Limited trials · D=Preliminary/traditional
HEPATOTOXICITY: dose-dependent. EFSA: do not exceed 800mg/day. Cases of acute liver failure with concentrated green tea extracts. Fasted state absorption increased but liver exposure also higher — take with food. Iron chelation: reduces non-haem iron absorption. Drug interactions: anticoagulants (inhibits platelet aggregation), bortezomib (anticancer drug antagonism), nadolol (P-gp substrate — increases exposure). Pregnancy: caffeine contribution from impure extracts.