Aging and organ failure are often discussed as distinct clinical entities, yet both arise along a continuous biological trajectory.

Here, we propose a unifying framework that conceptualizes aging-related disease progression as a time-dependent loss of cellular resilience culminating in irreversible organ failure.

Early aging is characterized by mitochondrial dysfunction, impaired repair capacity, and immune aging, during which functional states retain a degree of biological reversibility.

We define a critical “reversibility threshold” that separates modifiable dysfunction from irreversible structural and functional loss.

Aging medicine primarily targets upstream mechanisms operating before this threshold, aiming to preserve cellular resilience and delay irreversible decline.

In contrast, organ transplantation intervenes downstream, replacing organ function after reversibility has been lost without restoring the underlying aging biology.

By positioning aging medicine and transplantation on a single disease timeline, this framework clarifies their complementary but temporally distinct roles and highlights reversibility as a central organizing principle in aging-related disease biology.