Brewed green tea and concentrated green tea extract do not carry the same interaction risk. High-dose green tea or extract can reduce exposure to nadolol, atorvastatin, and raloxifene, while caffeine can add to stimulant effects.

Use with caution. Healthcare professional review recommended before use.

Contraindications

Cold weak digestion with loose stools and no heat signs
Use of concentrated catechin supplements in people with active liver injury unless specifically supervised

Cautions

Brewed green tea and concentrated green tea extract are not interchangeable; most serious liver-safety concerns involve high-dose supplements rather than ordinary tea.
Caffeine sensitivity may produce insomnia, palpitations, anxiety, reflux, or tremor in some users.
Heavy tea intake around meals may reduce nonheme iron absorption in susceptible people.

Drug Interactions

Drug Class / Substrate	Mechanism	Severity	Source
Nadolol and possibly other beta blockers	High-dose green tea reduced nadolol blood levels and may reduce its effectiveness.	Major	NCCIH Green Tea
Atorvastatin	Green tea extract can reduce atorvastatin blood levels.	Moderate	NCCIH Green Tea
Raloxifene	A controlled study found an interaction between green tea and raloxifene.	Moderate	NCCIH Green Tea
Stimulant medicines and caffeine-containing products	Green tea caffeine may add to insomnia, palpitations, anxiety, or tremor.	Moderate	NCCIH Green Tea

This information is for educational purposes only and does not constitute medical advice. Always consult a qualified healthcare provider before using herbal medicines, especially if you take prescription medications.