The clinical relevance of vitamin B3, nicotinamide (NAm), has been demonstrated in a variety of injury models to exert a number of therapeutic benefits in the protection against and treatment of traumatic brain injury (TBI). This study investigated its efficacy on recovery from TBI in animals of differing ages (6- and 10-months old) that were injured using the controlled cortical impact model and tested for motor and cognitive recovery following injury. Injured animals were treated with NAm or saline following injury and sham-injured animals were included as a control group. It was hypothesized that increasing age reduces the potentiality of recovery from injury as well as a decreased therapeutic benefit derived from the post-injury administration of NAm. The results found that neither the 6- nor 10-month old animals treated with NAm demonstrated improved functional recovery, indicating that age is an important factor in the vitamin’s efficacy. These results indicate that the success of possible treatments for TBI needs to also consider the effects of an individual’s age on the drug’s effectiveness.