Sarcopenia is the degenerative loss of skeletal muscle mass, quality, and strength associated with aging. The rate of muscle loss is dependent on exercise level, co-morbidities, nutrition and other factors. Sarcopenia can lead to reduction in functional status and cause significant disability. The muscle loss is related to changes in muscle synthesis signalling pathways. It is distinct from cachexia, in which muscle is degraded through cytokine-mediated degradation, although both conditions my co-exist. Sarcopenia is considered a component of the frailty syndrome.
The term sarcopenia is from Greek σάρξ sarx, "flesh" and πενία penia, "poverty".