Weight studies use 300–800 mg/day catechins for about 12 weeks; effects are small and concentrated fasting doses should be avoided
Reviewed · Published
Tea catechins
Green-tea polyphenols; brewed tea and concentrated EGCG extracts have different safety profiles.
Established functions
- Green-tea polyphenols; brewed tea and concentrated EGCG extracts have different safety profiles.
Dietary sources
- green tea
- sencha
Claims and evidence
Claims that Tea catechins alone prevents or treats disease, or invariably improves health without deficiency, are unsupported.
Japanese reference amounts
- Japanese adults (age and sex as specified): No Japanese DRI established
Amounts studied
- Weight studies use 300–800 mg/day catechins for about 12 weeks; effects are small and concentrated fasting doses should be avoided
Tolerable upper limits
- No Japanese UL; EFSA flags liver-injury concern at supplemental EGCG doses of 800 mg/day or more
Forms and bioavailability
Supplement forms: brewed green tea, standardized EGCG extract
- Fasting raises EGCG exposure; taking extracts with food is safer.
Safety and interactions
Adverse effects
- nausea
- liver injury
- insomnia when caffeinated
Medicine and nutrient interactions
- nadolol, stimulants, iron, hepatotoxic medicines
Contraindications and cautions
- Avoid concentrates with liver disease, pregnancy, or high caffeine sensitivity.
Practical selection
- Compare Tea catechins amount per serving, form, allergens, and batch testing; prefer a single-ingredient product suited to the intended use.
Sources and review
- Safety of green tea catechinsEuropean Food Safety Authority
Daiki Minaki (editorial and evidence review) ·