Previous studies have demonstrated that NAD+ levels fall as we age. Studies have also indicated the important role of NAD+ in keeping the body healthy and vital. It has therefore been long suspected that aging individuals and elderly would benefit most from supplementing NAD+ pre-cursors in order to boost NAD+ levels.
In this study twelve young and twelve old men received NR or placebo in a double-blind cross-over design. Before and 2 h after NR (500mg) or placebo supplementation, blood and urine samples were collected, while physical performance (VO2max, muscle strength, and fatigue) was assessed after the second blood sample collection. As mechanism of action the researchers hypothesized that NR supplementation would increase NADH and NADPH levels thus restoring the optimal redox status and improving exercise performance.
The results showed that NR supplementation increased NADH and NADPH levels in both young and old individuals. More precisely by 51% in young and 59% in old individuals after a single dose of 500-mg NR. This was accompanied by favorable outcomes generally appearing in old individuals: (1) decreased urine F2 isoprostanes, (2) tendency for increased erythrocyte GSH, (3) increased erythrocyte LDH activity, (4) increased isometric torque, (5) increased maximal lactate accumulation in blood after the fatigue test, and (6) increased resistance to fatigue.
You can find the study here.