https://www.mdpi.com/1422-0067/21/1/142/htm"... the lifespan extension ability of nicotinic acid (NA) depends on whether the intracellular level of NAD+ is lower than the sirtuin-saturating concentration in Hs68 cells and in C. elegans. Thus, the calorie restriction mimetic potential of NA should be limited to individuals with lower intracellular NAD+."
NAD+ Preservers ⇒ The Lifespan Extension Ability of Nicotinic Acid (niacin/vitamin B3)
The Lifespan Extension Ability of Nicotinic Acid (niacin/vitamin B3)
"The Lifespan Extension Ability of Nicotinic Acid Depends on Whether the Intracellular NAD+ Level Is Lower than the Sirtuin-Saturating Concentrations"