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Lean Muscle Mass

Meaning

Lean Muscle Mass (LMM) is the component of total body mass that excludes fat mass, primarily comprising skeletal muscle, connective tissue, water, and bone mineral. From an endocrine perspective, LMM is highly metabolically active and is a critical target tissue for anabolic hormones like testosterone and Growth Hormone. Maintaining high LMM is strongly associated with improved metabolic health, insulin sensitivity, and functional capacity, especially with advancing age. It is a key indicator of anabolic status.