SIRT3 or sirtuin 3 is a member of the sirtuin family of enzymes that depend on NAD+ to function. SIRT3 enzymes reside in mitochondria and play an essential role in maintaining mitochondrial health and metabolic control, including glucose metabolism, cellular energy (ATP) production, fatty acid oxidation, ketone production during fasting, and amino acid cycling. Mitochondria are central hubs for metabolic reactions and produce ~95% of the cell’s energy. As we age, mitochondrial function and levels of mitochondrial sirtuins decline, leading to metabolic dysregulation. Signal is designed to activate SIRT3 and thus promote mitochondrial and metabolic health.