The invention includes methods, kits, and pharmaceutical compositions for enhancing liver regeneration in a mammal in need thereof, comprising administering a therapeutically effective amount of an agent that increases nicotinamide adenine dinucleotide (NAD) activity. The methods may include administering a therapeutically effective amount of an agent that increases nicotinamide adenine dinucleotide (NAD) activity and a sirtuin 1 (Sirt1) agonist. The agent that increases NAD activity may be a NAD precursor. The NAD precursor may include one or more of tryptophan, nicotinic acid, nicotinic acid riboside, nicotinamide riboside (NR), nicotinamide, NADP, and NAD itself and a pharmaceutically acceptable salt thereof.