Mice dosed with NR had a longer lifespan than the water-only control group (Figure 6b). In the buried food test, mice treated with NR spent significantly shorter time before digging at the buried food site and finding the hidden food, indicating better odor detection...Supplementation of NAD+ through NR in water improved longevity and partially enhanced olfaction in aged mice. Our studies provide mechanistic and biological insights into the olfaction decline during aging and highlight the role of NAD+ for preserving smelling function and general health.