Damage Assays Rather than Biomarkers of Aging Aging is multiple forms of damage. Aging is primarily damage to macromolecules: proteins, lipids, carbohydrates, mitochondrial DNA and nuclear DNA (including telomeres). Aging damage is primarily due to ROS, RNS, sugars (glycation), radiation, pathogens, inflammatory cytokines, and accumulated toxins (metals, PCBs, dioxins, etc.). There is no singular aging process, but each species can be characterized by a maximum lifespan. Maximum lifespan for a species corresponds to the forms of aging damage that target the weakest link for the survival of that species. Biomarkers of aging attempt to measure biological age and thereby be a better predictor of life expectancy and future functionality than chronological age. Biomarkers of aging assume a singular underlying process, often measured by multiple components. There is no singular underlying aging process or biological age. Chronological age corresponds to biological age only for individuals of a species that have the potential to achieve maximum lifespan for that species. Endogenous and exogenous damaging agents can accelerate aging. Genetics can affect defenses against damage (antioxidant enzymes, heat shock proteins, etc.), damage repair, and molecular disposal and re-synthesis systems. Genetics can accelerate or decelerate aging. Most aging damage contributes to aging-associated diseases. The great majority of nonviolent, non-contagious deaths are due to aging-associated diseases. Different organs and tissues age (accumulate aging damage) at different rates. Death due to aging-associated disease will be caused by the most damage to the most vulnerable organ or tissue. Aging damage contributing to aging-associated disease is usually more organ- or tissue-specific than aging damage that does not contribute to aging-associated disease. Damage assays focus on the causes of aging, whereas attempts to find biomarkers of aging are a counterproductive distraction based on the misconception that there is a singular aging process. Comprehensive aging damage assays can allow for ranking forms of aging damage as contributors to morbidity and mortality, prioritizing interventions, and monitoring intervention effectiveness.