A cosmetic method for reducing the level of High-Mobility Group Protein B1 released from keratinocytes. The method includes identifying a target portion of skin where reduction of HMGB1 level is desired, and topically applying a nicotinamide riboside containing cosmetic composition to the target portion of skin during a treatment period, which is sufficient to reduce the level of HMGB1 released by keratinocytes. By reducing HMGB1 protein level, melanocyte dendricity can be reduced, thereby resulting in less melanin being taken into keratinocytes. The reduction in melanin transfer may provide a way to treat skin pigmentation disorders such as hyperpigmented spots.
