Sarcopenia is an aging process characterized by the loss of skeletal muscle mass and function. Although this condition primarily affects older adults, it is also associated with various diseases, physical inactivity, and nutritional deficiencies. Effective preventive measures include regular exercise, and adequate nutrition and protein intake to mitigate muscle atrophy. In this study, we investigated the effects of alanine on muscle tissue. Alanine supplementation increases physical performance and muscle function during physiological exercise in humans. To further explore its potential, we synthesized a D-alanine analog, D-Ala-Oi-pr-HCl, which demonstrated the ability to prevent muscle atrophy and increase muscle mass by downregulating myostatin expression both in vitro and in vivo. Furthermore, D-Ala-Oi-pr-HCl promoted the phosphorylation of Akt and ERK, both of which are associated with cell proliferation. However, the underlying mechanisms remain unclear. Notably, myostatin was inhibited by a D-alanine analog. These findings suggest that D-alanine analogs may serve as new therapeutic agents for muscle atrophy, providing valuable insights for future biomedical applications.