A pharmacokinetic study of NAD replenishment therapy using Nicotinamide Riboside

Abstract

Parkinson`s disease (PD) is a major cause of death and disability, and currently only symptomatic treatment is available. Nicotinamide adenine dinucleotide (NAD) is a crucial molecule for maintaining life and promoting good health by regulating vital cellular functions including energy metabolism, redox balance, and DNA repair. Recently NAD replenishment therapy has moved into focus as a putative treatment for PD. Nicotinamide riboside (NR), a vitamin B3 precursor of NAD synthesis, is commonly used in clinical trials, and while it has shown potential to increase NAD and possibly impact PD progression, many important questions remain unanswered. In this study, the pharmacokinetics of NAD augmentation by NR supplementation in the blood and brain of six healthy volunteers were investigated. The results showed a surprisingly slow increase of NAD levels in the blood over several days, as well as a slow decrease before approaching baseline levels. Brain NAD measurements fluctuated and were less clear to interpret but showed a similar slow change rate at least in some individuals. The study provided important information about development of NAD levels following NR supplementation and contributes as a stepstone further towards fully understanding NR as a potential NAD replenishment therapy.