Skeletal muscle atrophy stems from hyperactivation of three major protein degradation systems: the ubiquitin-proteasome system, autophagy-lysosome pathway, and calpain/caspase cascades, which overwhelm the anabolic IGF-1/PI3K/Akt/mTOR pathway that promotes protein synthesis. The research identifies catabolic drivers including FOXO transcription factors, myostatin signaling, NF-κB inflammation pathways, and JAK/STAT cascades, while implicating oxidative stress, mitochondrial dysfunction, and novel cell death mechanisms like ferroptosis and pyroptosis. This comprehensive mapping represents a paradigm shift from viewing muscle wasting as simple protein imbalance to understanding it as a complex network disease. The practical implications are sobering—current interventions including exercise, pharmaceuticals, and nutrition show limited efficacy precisely because they target individual pathways rather than the interconnected system. The identification of epigenetic alterations and endoplasmic reticulum stress as contributors opens new therapeutic avenues, though emerging strategies like stem cell therapy and mitochondrial quality control remain experimental. For aging adults and patients with chronic diseases, this research suggests future treatments will require precision, multi-target approaches rather than single-drug solutions, fundamentally changing how we approach muscle preservation.