The primary objective of modern medicine is to extend human life expectancy. Currently, the majority of hospital patients across various clinical settings are elderly or advanced-age individuals, often with multiple comorbidities and age-related alterations in peripheral tissues. One such alteration is sarcopenia, a progressive decline in muscle mass, strength, and function, which significantly increases the risk of disability and mortality in older adults. Sarcopenia is associated with numerous adverse outcomes, and its underlying mechanisms are the subject of ongoing research. This narrative review discusses the epidemiology, pathophysiology, and diagnostic criteria for sarcopenia. It also examines the connections between sarcopenia and metabolic dysfunction-associated steatotic liver disease (MASLD), highlighting potential treatment approaches for the coexistence of these two pathologies.