Aging is the primary risk factor for cardiovascular diseases (CVD), the number one cause of death in developed societies. Systolic blood pressure (SBP) increase with age and is a key intermediary factor linking aging to increased CVD risk. The primary mechanisms underlying the age-associated increase in SBP is stiffening of the large elastic arteries, which is mediated by increases in oxidative stress, inflammation, and vascular smooth muscle tone. Regular caloric restriction is effective at lowering SBP in middle-aged and older adults; however, adherence to caloric restriction is poor and may be detrimental to normal weight older adults due to reduced skeletal muscle mass and bone mineral density. Therefore, identification of more practical alternative interventions that mimic the beneficial effects of caloric restriction, with stronger adherence and less risk of adverse consequences, is of significant biomedical importance. Nicotinamide riboside is a naturally occurring precursor of nicotinamide adenine dinucleotide (NAD+), a critical mediator of the beneficial effects of caloric restriction, and therefore a novel caloric restriction mimetic compound. We recently completed the first pilot study of nicotinamide riboside supplementation in healthy middle-aged and older adults and demonstrated that 6 weeks of supplementation decreased systolic blood pressure (SBP) by 8 mmHg in individuals with baseline SBP of 120-139 mmHg (elevated SBP/stage 1 hypertension) compared with placebo, and lowered arterial stiffness, a strong independent predictor of CVD and related morbidity and mortality. As a next translational step, we will conduct a randomized, placebo-controlled, double-blind clinical trial to further assess the safety and efficacy of oral nicotinamide riboside (3 months vs placebo) for decreasing SBP and arterial stiffness in middle-aged and older men and women with SBP between 120 and 139 mmHg at baseline.