Green tea (Camellia Sinensis) is a plant typically steeped in hot water and consumed as tea. It is widely regarded as one of the healthiest beverages in existence due to the plethora of antioxidants and nutrients contained in its leaves. Most of its benefits are attributed to a class of water-soluble polyphenols (usually referred to as catechins) extracted from the leaves which is then consumed via liquid form (in tea) or supplements.
EGCG (Epigallocatechin Gallate) is the most well known and studied of the numerous Green Tea catechins. EGCG and the other catechins are potent antioxidants that combat free radicals in the body. These antioxidants protect cells from oxidative damage, and help resist the effects of aging and other assorted maladies.
Green tea, and its extracts have been heavily researched for its beneficial effects in a wide range of fields including: obesity, Type II Diabetes, aging, assorted cancers, cardiovascular health, metabolic disorders, mental and physical performance.
In terms of dosing green tea extract for maximal benefit, much of the research indicates that intakes of 400-500mg EGCG equivalent per day yield the most effect.