In brief: Green tea comes from Camellia sinensis and contains catechins such as EGCG as well as caffeine. Brewed tea can fit a balanced diet, while concentrated extracts need separate safety consideration.
Brewed tea versus extract
| Form | Practical note |
|---|---|
| Brewed tea | Usually much lower catechin exposure |
| Matcha | More leaf material is consumed |
| Extract capsules | Can provide high EGCG doses |
| Low-caffeine tea | Often easier for sensitive people |
Caffeine and sleep
Caffeine can improve alertness but may also cause palpitations, restlessness or sleep problems.
Extracts and liver safety
EFSA considers brewed green tea generally safe, while concentrated catechin supplements raise more concern; intakes at or above 800 mg EGCG/day have been associated with early signs of liver injury.[1]
FAQ
Is green tea a cancer treatment?
No.
Is matcha automatically healthier?
No.
Can green tea affect iron absorption?
Yes, polyphenols can reduce non-haem iron absorption.
Are extracts the same as tea?
No. Extracts can deliver much higher EGCG doses.
Conclusion
Green tea is primarily a beverage. Extracts deserve greater attention to dose, product quality and liver risk.
