NMNH supplementation, NAD+ steadily increased for up to 6 hours and remained stable for 24 hours, while NMN reached its plateau after only 1 hour.
 
Supplementation with NAD+ enhancers has emerged as a valid strategy to treat or alleviate features of metabolic and age-related diseases in several preclinical models. To assess the in vivo effects of NMNH in comparison with NMN, we injected C57BL/6N mice with vehicle (PBS) or 250 mg/kg of NMN or NMNH, which was followed by sequential blood sampling (at 1, 4, 20 hours) and, after 24 hours, sacrifice for tissue collection.
 
NMNH showed a potent NAD+-boosting effect in blood, efficiently increasing NAD+ levels after 1 hour and to a much higher extent than NMN (Figure 6A). Strikingly, while blood NAD+ content after NMN supplementation declined to basal levels after just 4 hours, NMNH administration sustained a 2-fold NAD+ increase for at least 20 hours following the first injection. This was also reflected in the blood samples taken 4 hours after the second IP injection, as an increase in NAD+ was only detected in NMNH-treated animals (Figure 6A).