THE ARISING · Longevity & Healthspan
Blood NAD Levels Tracked Heart Disease, Not Age, in 1,068 Adults
A popular idea in the longevity world holds that NAD, a molecule your cells use to make energy, falls steadily as people get older. A new study of 1,068 adults found that whole-blood NAD did not follow that pattern.
The work, published in Nature Metabolism in 2026, is an observational study in people. Researchers made 1,340 whole-blood NAD measurements across 1,068 adults and compared the results by age, sex and health status.
In healthy people, NAD levels did not decline with age. They stayed stable in men and rose with age in women, according to the paper.
Levels did differ by health. Whole-blood NAD was lower in people with chronic diseases, specifically cardiovascular disease and hypertension, the term for high blood pressure. The authors conclude that blood NAD tracks cardiovascular disease rather than chronological age.
That matters for the case behind NAD booster supplements. Many are sold on the premise that NAD drops with age and that restoring it could support healthy ageing. In this large sample of healthy adults, the age-related drop in blood NAD was not there.
The authors are careful about what the result means for treatment. The research was not designed to investigate causality, they write, so the data do not provide direct evidence that NAD supplementation could treat cardiovascular disease or hypertension. Lower NAD in these conditions could be a result of illness, a contributor to it, or both. Only whole blood was measured, so the findings speak to blood rather than to other tissues.
Studies that follow people over time to see whether changes in blood NAD come before or after heart disease and high blood pressure.