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SupplementModerate evidenceImmunity

Green tea / EGCG

Meta-analysis signal for modest LDL and BP reduction; hepatotoxicity at high-dose extract limits safe upper bound.

Why

Green tea (Camellia sinensis) catechins, principally epigallocatechin gallate (EGCG), have one of the largest observational and RCT bodies of any dietary phytonutrient. Meta-analyses of RCTs report modest reductions in LDL cholesterol, systolic blood pressure, and body weight. The cardiometabolic signal at moderate intakes is consistent; the cancer-preventive signal is observational. A practical limit is hepatotoxicity at high-dose extract intake, EFSA has flagged 800 mg/day EGCG from supplements as the threshold above which hepatotoxic effects have been reported.

How it works

EGCG and related catechins inhibit hepatic HMG-CoA reductase, modulate fatty acid oxidation via AMPK activation, and reduce dietary lipid absorption. Antioxidant effects on vascular endothelium and modest thermogenesis via norepinephrine signalling.

Expected onset · Lipid effects over 8–12 weeks; weight effects over 12 weeks

How to take

Dosage

Standardised extract: 200–400 mg EGCG per day from supplements (EFSA caution above 800 mg/day). Tea form: 3–5 cups/day delivers approximately 200–300 mg EGCG.

Timing

With meals to reduce GI upset; avoid late in the day if caffeine-sensitive

On the label

Standardised extract with stated EGCG content. Decaffeinated forms exist. Drink as tea where possible rather than high-dose extract.

Ideal for

Adults with mild dyslipidaemia or modest weight-management goals; people seeking the catechin intake of green tea drinkers without the volume.

Safety

Hepatotoxicity reports at high-dose extract intake, EFSA threshold is 800 mg/day EGCG from supplements. Take with food. Avoid on empty stomach. Caffeine content (~30–50 mg per cup), relevant for those sensitive. Reduces non-haem iron absorption. Separate from iron supplements by 1–2 hours. Caution with warfarin (vitamin K content varies). Pregnancy: limit caffeine; extract doses unstudied.

Evidence

At a glance

Zheng 2011 Am J Clin Nutr meta-analysis (14 RCTs, n=1,136): green tea reduced total cholesterol by 0.18 mmol/L and LDL by 0.15 mmol/L vs control. Onakpoya 2014 meta-analysis: systolic BP reduced by ~2 mmHg. EFSA 2018 opinion flagged 800 mg/day EGCG from supplements as the threshold for hepatotoxic effects, practical reason to favour tea form over high-dose extract.

Where to get it

Shop Green tea / EGCG on Amazon

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