In diethoxycarbonyl-1,4-dihydrocollidine (DDC) diet-fed KK-Ay mice, a model of skeletal muscle atrophy, semaglutide restored intramuscular mRNA and protein levels of PGC-1α, mitochondrial transcription factor A (mtTFA), and sirtuin 1 (SIRT1), key regulators of mitochondrial biogenesis [26]. Here, SIRT1 is linked to muscular atrophy.