A shared framework for the biology of aging
The hallmarks of aging are a set of interconnected processes proposed to describe what changes at the cellular and molecular level as organisms grow old. First published as nine hallmarks in 2013 and expanded to twelve in a 2023 update, they give researchers a common vocabulary. The twelve are genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, disabled macroautophagy, deregulated nutrient sensing, mitochondrial dysfunction, cellular senescence, stem cell exhaustion, altered intercellular communication, chronic inflammation, and dysbiosis.
The original authors grouped them into primary causes of damage, antagonistic responses that turn harmful over time, and integrative hallmarks that emerge when the others overwhelm the system.
How the hallmarks interlock
A central point of the framework is interdependence: no single hallmark fully explains aging, and intervening in one often shifts the others. For example, genomic instability and telomere attrition can drive senescence, which then alters intercellular communication and inflammation.
The hallmarks are a useful organizing model rather than a finished or fully agreed account, and their relative weight is still researched. This is general educational information on aging biology, not medical advice; consult a qualified professional.