The evidence that NAD doesn’t enter most cells is overwhelming:
“NAD is considered impermeable to the plasma membrane, and NAD administration cannot efficiently increase NAD levels. Therefore, NAD precursors...are utilized to increase NAD levels in rodents and humans” -- Journal of Biomedical Science, May 11, 2019
“Increasing evidence indicates that NAD+ cannot enter cells directly through the plasma membrane and that it must be converted into smaller, less charged molecules to enter cells.” -- Aging and Disease, December 1, 2021
“NAD+ is highly polar and, like other nucleotides and dinucleotides, is not readily taken up by cells” -- Cell Metabolism, December 2, 2014
“In general, cells are unable to take up NAD+...” Cell Metabolism, March 6, 2018
“NAD+ cannot be taken up directly by the cell, but its precursors can...” Trends in Immunology, April 1, 2022
NAD injections and IVs are a big business, but there are important questions about cost, effectiveness, safety, and benefits Before spending hundreds of dollars to inject NAD into your veins, consider the costs and benefits of this method of NAD replenishment. Not only is it the most expensive...
www.scienceofnad.com
Accumulating evidence suggests that active maintenance of optimal levels of the essential pyridine nucleotide, nicotinamide adenine dinucleotide (NAD+) is beneficial in conditions of either increased NAD+ turnover or inadequate synthesis, including Alzheimer’s ...
www.ncbi.nlm.nih.gov