Nicotinamide (Nam) has recently been characterized as an agent for tissue regeneration due to the observed pro‑proliferation effects. However, the effect of Nam on liver regeneration remains undetermined. In the present study, the potency of Nam as a regimen to promote liver regeneration and restore liver function was evaluated following partial hepatectomy (PH) on C57BL/6 mice. Ki‑67 immunohistochemical and cell cycle analyses demonstrated that exogenous Nam supplementation promoted the proliferation of hepatocytes and accelerated the recovery of liver tissue. The addition of Nam protected liver function following PH, as evidenced by hematoxylin and eosin staining of liver tissue morphology and measurement of serum liver injury markers. Notably, immunoblotting results revealed that the expression and activity of NAD‑dependent protein deacetylase sirtuin‑1 (SIRT1) were significantly upregulated following treatment with Nam, suggesting that Nam may promote liver regeneration through activation of SIRT1. The present study demonstrated that Nam regulated the process of liver regeneration and improved liver function by activating SIRT1, suggesting that Nam has the potency to be used for promoting liver regeneration following surgical resection.