(2) Altered hormone levels: Hormonal imbalances characterized by decreased levels of insulin, growth hormone, sex hormones (particularly testosterone), and insulin-like growth factor-1 (IGF-1) [44], together with increases in the levels of angiotensin II, glucocorticoids, and parathyroid hormone [45], and corresponding receptor interactions can ultimately enhance protein degradation and suppress protein synthesis, contributing to sarcopenia onset. This evidence concerns the gene PTH and sarcopenia.