Sclerostin is a protein secreted by osteocytes whose encoding geneSOSTis regulated by mechanical stimuli, cytokines, and all-transretinoic acid (ATRA) and mediates antianabolic effects on bone formation as an inhibitor of the canonical Wnt/β-catenin pathway. Interestingly, skeletal muscle has recently been identified as another source of sclerostin, suggesting that the musculature may play an important role in maintaining bone mass. However, regulators of muscularSOSTexpression are virtually unknown. This study investigates the influence of ATRA and the provitamin A derivative beta-carotene (β-C) on sclerostin synthesis in muscle cells. The impact of ATRA, its synthetic analog TTNPB, and β-C onSosttranscription was analyzed by qRT-PCR in C2C12 myotubes and the secreted sclerostin protein by ELISA. ATRA strongly increases the sclerostin synthesis in C2C12 myotubes in a dose-dependent manner. The stimulating effect of ATRA and TTNPB onSostis largely reduced in the presence of the retinoic acid receptor inhibitor AGN193109. β-C also increases theSostexpression, but this effect vanishes when β-C is coincubated with beta-carotene 15,15′-monooxygenase 1 (BCMO1)-specific siRNA. Thus, ATRA is a potent stimulator of sclerostin release in muscle cells. β-C can also increaseSostmRNA abundance, but this effect depends on the conversion to a retinoid.