The present invention relates to a method of treating or preventing DNA damage in a cell or cellular senescence of a cell or induction of the senescence associated secretory phenotype (SASP) in a cell, or for treating or preventing the effects of aging, or for preventing or treating cellular senescence and/or induction of SASP associated with high caloric intake or obesity, or for reducing the side effects of chemotherapy, radiotherapy, corticoid treatment, anti-retroviral treatment, or PPARγ agonist treatment, comprising administering an effective amount of an NAD+ agonist.