Polyphenols in red wine are bioactive compounds with positive effects on health and disease prevention. White grape musts and wines have a lower concentration of phenolic compounds compared to the red ones and are therefore considered less beneficial to health. In Andalucía, a region located in the South West of Spain, Pedro Ximenez white grapes are desiccated under the sun for a week before they are pressed and the juice (must) is obtained. This ancient procedure increases the variety and content of polyphenols present in the Pedro Ximenez must (PXM). We incorporated PXM into the daily diet of aged Mus spretus mice (24 months) and investigated their properties by comparing several parameters determined in these old mice with those measured in young mice (two months old). Biochemical, histological, and transcriptional analyses indicated that PXM exhibited potent antioxidant properties, promoted the normalization of the biotransforming ability of several cytochromes, i.e., the P450 family, in the liver, and regularized hepatic apoptosis, promoting proliferation instead. Our data indicated that PXM possesses a profound ability to promote liver regeneration in terms of both the structure and the function, thus contributing to a healthy aging process.