Epigallocatechin-3-gallate (EGCG, main green tea polyphenol)

EGCG is actively sold as a «natural oncoprotector» based on laboratory tumour cell proliferation inhibition data. Filippini 2020 Cochrane review included 142 studies on green tea and cancer prevention: data inconsistent; for breast, prostate, stomach and lung cancer – inconclusive evidence; no evidence base to recommend EGCG supplements for cancer incidence reduction. USPSTF 2022 recommends against routine vitamin-mineral supplement use for cancer prevention (D recommendation). EFSA 2018 warned about EGCG hepatotoxicity risk at >800 mg/day – such doses are common precisely in «concentrated» supplements marketed as oncoprotectors. If EGCG was recommended for «cancer prevention» or adjuvantly with an oncological diagnosis, consider seeking a second opinion from an oncologist.

EGCG is sold as a «natural cardioprotector» via oxidised LDL reduction and endothelial function improvement. Several meta-analyses showed modest total cholesterol (−5–7 mg/dL) and LDL (−4–6 mg/dL) reduction with catechins 200–800 mg/day, far less than statin effect (30–55% LDL reduction from baseline). ESC dyslipidaemia 2024 at LDL >1.8–3.0 mmol/L (depending on CV risk) lists statins (atorvastatin, rosuvastatin) first-line; green tea extract is not in guidelines. EFSA 2018 warned about EGCG hepatotoxicity at >800 mg/day – relevant when choosing high-dose «cardio complexes». If EGCG was recommended as a statin substitute, consider seeking a second opinion from a cardiologist.

EGCG is sold as a «natural fat burner» via thermogenesis stimulation and lipogenesis inhibition. Phung 2010 systematic review of 11 RCTs in 936 patients showed clinically minor mean weight loss of 1.3 kg over 12 weeks with catechins 270–1200 mg/day vs placebo. EFSA 2018 warned about EGCG hepatotoxicity at >800 mg/day, while most «fat burning» supplements contain precisely 500–700 mg EGCG per capsule + extra caffeine. For sustained weight loss ESC 2024 and SEEN recommend 500–750 kcal/day deficit, Mediterranean diet, 150–300 min/week physical activity; at BMI ≥30 or ≥27 with complications – pharmacotherapy (GLP-1 agonists semaglutide/liraglutide, lysosomal lipase orlistat) and bariatric surgery. If EGCG was recommended as a substitute for proven weight loss interventions, consider seeking a second opinion from an endocrinologist.

EGCG is actively sold in the longevity segment via oxidative ageing theory and translation from mouse data. No RCTs with lifespan, biological ageing slowing or all-cause mortality endpoints in humans. Most important – EFSA 2018 and LiverTox NIH describe a series of drug-induced liver injury (DILI) cases with high-dose EGCG supplements: hepatocellular pattern, 1–5 months latency, sometimes requiring discontinuation and rarely transplantation. AASLD 2023 DILI practice guidance specifically flags green tea extract as a frequent cause of herb-induced liver injury in the US and EU. If EGCG was recommended as «natural anti-aging» in long-term protocols, consider seeking a second opinion from a general practitioner and monitor ALT, AST, bilirubin.