beginning at 4 months of age, with 2% green tea extract, did not significantly extend their lifespan but diminished the risk of mid-life deaths in female mice [35]. Therefore, the antiaging effect of green tea extract and EGCG may depend on the mouse's genetic background and/or the presence of specific environmental factor such as nutritional stress. In addition, the treatment dose, duration and animal age at which the intervention begins may all affect the outcome.