Compound or practice · Supplement
Green Tea Extract (EGCG)
Modest metabolic and cardiovascular benefits from catechins — and a real, if uncommon, liver-toxicity signal at high concentrated doses.
- Overall grade
- Grade C
- Last revised
- 2
- graded outcomes
- 0
- references listed
A structured monograph in Prometheus's bundled library. Its grades are the monograph's own reading of the evidence, not a peer-reviewed review.
2 at grade C — 2 graded rows
What is known
Each outcome with its grade (how strong the evidence is, A to D), the size of the effect where the entry records one, and how often studies agree.
- Body weightEvidence grade C
Minor
Smallmixed
- Liver injury (high-dose extract)Evidence grade C
Rare but serious
Smallmixed
What is uncertain
Read off the same rows as above. Nothing here is added that the entry does not itself record.
- Thin evidence: Body weight (grade C); Liver injury (high-dose extract) (grade C).
The evidence in words
What it is
Green tea extract concentrates catechins, chiefly EGCG, plus caffeine. Drinking green tea is benign and pleasant; high-dose concentrated extracts are a different risk profile.
How it works
Catechins have antioxidant activity and modestly influence fat oxidation and endothelial function, often synergizing with the caffeine present.
What the evidence shows
Small effects on body weight, lipids, and blood pressure in meta-analyses — real but minor, and easy to overstate. The important caveat is safety: concentrated EGCG supplements are linked to rare but serious liver injury, prompting regulatory warnings, particularly when taken fasted at high doses.
How to use it
Prefer brewed green tea. If using extract, keep EGCG modest (≤300–400 mg/day), take with food, and stop if any signs of liver trouble.
Safety & interactions
Brewed tea is safe. Concentrated extracts carry a rare hepatotoxicity risk; avoid high fasted doses.
Bottom line
Drink the tea for a pleasant, mild metabolic nudge. Be cautious with concentrated EGCG capsules — the weight-loss upside is small and the rare liver risk is not.
How it is used
As the entry records it, from the studies it summarises. Not a recommendation for you — doses that suit a trial population may not suit you.
- Prefer tea
- Brewed tea; if extract, ≤300–400 mg EGCG with food.
Related reading
Entries that share this one's tags or conditions.
- Green Tea Extract (EGCG) for Body weightEvidence grade C — MinorEvidence grade C
- Green Tea Extract (EGCG) for Liver injury (high-dose extract)Evidence grade C — Rare but seriousEvidence grade C
- Green Tea Extract (EGCG): dosage and how to take itBrewed tea; if extract, ≤300–400 mg EGCG with food.Evidence grade C
- Green Tea Extract (EGCG): side effects, safety & interactionsBrewed tea is safe. Concentrated extracts carry a rare hepatotoxicity risk; avoid high fasted doses.Evidence grade C
Sources
This entry lists no references of its own.
Last revised . A grade is this entry's reading of the evidence, not medical advice.