Biological rhythm is a phenomenon that encompasses the sensing of time, physiological activities, and metabolism under the influence of time. Circadian rhythm, commonly referred to as the biological clock, is the most prevalent, significant, and extensively researched biological phenomena, influences various physiological processes including body temperature regulation, alertness, appetite, metabolism, hormone secretion, and sleep patterns. Its dysregulation is associated with an increased susceptibility to obesity, type II diabetes, cardiovascular disease, psychiatric disorders, and certain types of cancers. Furthermore, disorders of the endogenous circadian timing system can also result in related sleep disorders. Supplementation of nicotinamide mononucleotide (NMN), a precursor to NAD+, could effectively restore disrupted circadian rhythms. NAD+ metabolism is intricately linked to the regulation of biological rhythms primarily through the transcriptional regulation of clock genes by NAD+-dependent deacetylases such as Sirtuins, PARP, and CD38.