The concentration of the endogenous dipeptide carnosine reaches tens of millimoles in human muscle tissue. Vast data on various carnosine functions have accumulated over more than 100 years of research, the anti-aging effect being thought the most important. The effect of carnosine was studied in cultured cells. Apart from the well-known effects of increasing the Hayflick limit and causing morphological rejuvenation of cells, carnosine was found to stimulate cell divisions in the colony formation assay and to inhibit the cell transition to quiescence. A transcriptome analysis showed that carnosine-induced changes are mainly related to the positive regulation of the cell cycle at all of the levels from the onset of DNA synthesis to chromosome condensation. It was assumed that the cell cycle-stimulating potential underlies the rejuvenating effect of carnosine and that high carnosine concentrations in muscle tissue are necessary for the recovery (regeneration) of muscles after intense exercise apart from their role as a physiological buffer.