Does NAD+ decline with age? Blood and tissue data tell different stories

Researchers measured NAD+, a molecule cells use to produce energy, in blood samples from people of different ages. They also examined NAD+ in human tissues, including muscle. Blood levels did not show a clear age-related drop, while some tissue measurements were lower in older people. The results differed depending on which body sample was tested.

What this means for you: This does not show that NAD+ supplements are needed or will slow aging. Blood tests may not reflect what is happening inside organs, and the study cannot prove that raising NAD+ improves health.