NAD+ (nicotinamide adenine dinucleotide) is a coenzyme that occurs in all living cells and plays a crucial role in metabolism. It consists of two nucleotides, namely nicotinamide and adenine, which are linked together via a phosphate group. NAD+ is involved in many biochemical reactions, particularly redox reactions in which electrons are transferred from one chemical compound to another. It acts as an electron carrier and can switch between the oxidised form (NAD+) and the reduced form (NADH). These redox reactions are crucial for energy metabolism as they enable the conversion of nutrients such as carbohydrates, fats and proteins into ATP (adenosine triphosphate), the main source of energy for cells. In addition, NAD+ plays an important role in the activation of sirtuins, a family of proteins that act as epigenetic regulators and are involved in the regulation of cell metabolism, DNA repair, inflammatory responses and cell ageing. NAD+ binds to and activates sirtuins, leading to a variety of cellular effects, including promoting mitochondrial function, improving insulin sensitivity and inhibiting inflammatory responses. As we age, NAD+ levels in the body decline, which is associated with the ageing process and various age-related diseases. This decline can be due to various factors, including genetic changes, environmental factors and metabolic dysfunction. The interest in increasing NAD+ levels is that it could potentially have positive effects on health and ageing. There are various approaches to increasing NAD+ levels, such as the use of dietary supplements like nicotinamide riboside (NR) or nicotinamide mononucleotide (NMN). These compounds are converted to NAD+ in the body and can increase NAD+ levels. However, it is important to note that further research is needed to understand the long-term effects, potential risks and optimal dosing of these approaches. Overall, NAD+ is an important coenzyme that plays a central role in metabolism and cell function. The study of NAD+ and its role in health and aging is an active area of research that requires continued scientific attention and investigation to gain a comprehensive understanding.following