Green Tea Extract (EGCG)

Supplements · Cognitive & Vitality Herbs · Supplement, Typed Supps

Concentrates the compound behind green tea’s reputation into a capsule.

Stage by stage

Intake (Capsule): Catechins like EGCG absorb less efficiently than many nutrients.
Small intestine (Improves on empty stomach): Absorption improves somewhat when taken without food.
Bloodstream (Antioxidant activity): Circulates with antioxidant activity.
Metabolism & cardiovascular markers (Modest studied effects): Studied for modest effects on metabolism and cardiovascular markers.

What the evidence supports

Producing modest, short-term help with weight loss or maintenance — limited evidence. Meta-analyses show small effects of doubtful clinical importance, possibly driven partly by caffeine.
Lowering LDL cholesterol modestly — limited evidence. Some trials and meta-analyses show small reductions, but effect sizes are small and inconsistent.
Evidence that it causes Concentrated EGCG causing liver injury at high doses — moderate evidence. EFSA concluded that supplemental doses at or above 800 mg EGCG/day are associated with raised liver enzymes and rare serious injury; brewed tea is not implicated.

Typical dose

Studies used a wide range; keep total EGCG below 800 mg/day and take it with food

Upper limit: EFSA flags 800 mg EGCG/day from supplements as the level above which liver risk rises

Timing

With food — concentrated extracts on an empty stomach have rare high-dose liver-related reports.

Time to effect

Weeks: Any reported metabolic effect in studies.

Medication interactions

Oral iron / iron-rich meals: Green tea catechins bind non-haem iron and can more than halve its absorption. (moderate)
Nadolol (beta-blocker): Green tea markedly reduces nadolol blood levels (up to ~85% in one study), blunting its effect. (moderate)

Common myth

“More green tea extract is always safer than the tea itself.” In reality: Concentrated extracts deliver far more catechins than a cup of tea — rare but serious liver reports specifically involve high-dose extracts, not the beverage.