Green Tea

Green tea extract · Camellia sinensis · EGCG · Epigallocatechin gallate

Snapshot

Indications	Contraindications
Weight management¹ LDL cholesterol lowering¹ Cognition and mood² Blood pressure support³ Postmenopausal adiposity⁴ Periodontitis alongside root planing^{5, 6}	Liver disorder⁷ Pregnancy or breastfeeding⁷ Iron deficiency⁷

Green tea comes from the unfermented leaves of Camellia sinensis, and extracts concentrate its catechins, chiefly epigallocatechin gallate (EGCG), alongside caffeine⁸. EGCG is linked to nitric oxide-mediated vasodilation⁸. People take it for modest weight loss and cholesterol lowering, with cardiovascular and cognitive support following from the same catechin and caffeine effects¹.

Randomized trials show small reductions in total and LDL cholesterol, and weight effects depend on product composition and activity level¹. Cancer-prevention results are inconsistent in a Cochrane review⁹. A systematic review reports benefits for memory and attention, most clearly with caffeine and theanine together. About 28,000 products list green tea, mostly capsules of leaf powder or extract; see Form comparison.

Liver injury is the consequential caution: it is uncommon, arises mainly with extract capsules and tablets, and is more likely with a specific immune gene variant¹. The same source reports green tea lowers blood levels of nadolol and atorvastatin and advises talking with a health care provider before using green tea supplements¹.

Last updated October 16, 2026. Read how we make monographs.

In the full monograph

72 sources, 59 studies

When to useThe situations practitioners use it for, each with the reason and the study behind it.
SafetyWho should avoid it, who needs extra care, and the side effects reported in studies.
InteractionsThe medicines and supplements it interacts with, the effect of each, and what labeling says to watch.
Protocol notesThe doses used in studies, how and when they were taken, and how the forms on the market compare.
How it worksWhat it is and how it works in the body, in plain terms.
Published studiesThe studies behind each use, popular claims checked against them, and trials still under way.
Word of mouthWhat patients and practitioners report online, kept separate from the clinical evidence.
Clinical perspectiveA closing read of where the evidence is solid, where it is thin, and what has not been studied.

Snapshot

In the full monograph

Sources