Effects of Intravenous Nicotinamide Riboside on Muscle NAD+: Preclinical Findings

Synopsis

Although nicotinamide riboside (NR)—a common NAD+ booster—is believed to enhance energy metabolism, clinical studies have shown little effect on muscle function or insulin sensitivity. To test whether this is due to poor absorption, researchers gave mice chronic NR infusions directly into the bloodstream to ensure higher delivery to skeletal muscle. The treatment successfully increased muscle NAD+ levels, but it did not improve mitochondrial respiration, insulin sensitivity, or gene activity, even when combined with pterostilbene (PT) or exercise. These results suggest that simply increasing NAD+ in muscle tissue is not enough to enhance metabolic performance, indicating that NAD+ precursor supplements may have limited benefits for muscle health in the absence of other cellular adaptations.

Journal

iScience