Clinical studies investigating the role of Nicotinamide adenine dinucleotide (NAD+) supplementation in managing stress, anxiety, depression, and addiction have yielded intriguing findings. NAD+ is a coenzyme involved in various cellular processes, including energy metabolism and DNA repair, with emerging evidence suggesting its potential role in mental health and addiction disorders. Through its involvement in cellular energy production and regulation of oxidative stress, NAD+ supplementation has shown promise in improving mood, reducing anxiety, and alleviating symptoms of depression in human subjects. Furthermore, NAD+ therapy has been explored as a potential treatment for addiction, particularly substance use disorders, by promoting detoxification, reducing cravings, and supporting neuroplasticity. While further research is needed to fully understand the mechanisms and optimize treatment protocols, these clinical studies offer hope for novel approaches to addressing mental health challenges and addiction issues through NAD+ supplementation.