Our major findings were as follows: (i) GA promotes myoblast differentiation without cytotoxicity, (ii) GA promotes mitochondrial biogenesis via an increase in the levels of representative mRNAs (Sirt-1, Nrf1, Nfe2l2, Tfam, and Tfb1m) that regulate mitochondrial biogenesis, (iii) GA increases the intracellular levels of several amino acids and their metabolites, and (iv) GA ameliorates Dex-induced muscular atrophy. This evidence concerns the gene SIRT1 and muscular atrophy.