Cellular senescence is characterized by cellular hypertrophy: cell growth in the absence of cell division. The genes that regulate this process can be activated or inactivated by numerous plant polyphenols such as resveratrol, quercetin, butein, fistein, piceatannol, curcumin. Many of these substances have been shown to lengthen the lifespan of invertebrates. Many of these compounds have other potential beneficial effects on lifespan as antiatherogenic or antineoplastic agents. Challenges to human testing of such substances on lifespan include determination of dosage, low bioavailability, time and resources necessary to conduct tests, and understanding which formulation of substances to use.