Low blood NAD levels track heart disease and hypertension, not aging

Adults with cardiovascular disease and hypertension had lower levels of nicotinamide adenine dinucleotide (NAD) in their blood than healthy adults, while healthy adults showed no age-related drop in the molecule, according to a study published Nov. 4 in Nature Metabolism.

NAD is a coenzyme cells rely on for energy metabolism, and it’s become a focal point of aging research. Earlier studies have shown NAD declines with age in skeletal muscle, brain and skin, which has fueled rapid growth in supplements containing NAD precursors such as nicotinamide mononucleotide (NMN) and nicotinamide riboside (NR), the authors noted. But whether NAD in whole blood, the easiest place to measure it, also falls with age has been unsettled, with prior studies reporting conflicting results.

To sort that out, researchers from Vilnius University and two Lithuanian companies, SensoLife and LifeLab1, took 1,340 measurements from 1,068 adults in Lithuania between 2023 and 2025. Participants collected finger-prick dried blood spots in the morning after an overnight fast, and the samples were analyzed for total whole-blood NAD.

Out of the 707 healthy adults who reported no chronic disease and no NAD supplement use, researchers found that NAD did not decline with age. Levels stayed flat in men and rose slightly in women, an increase the authors said has not, to their knowledge, been reported before. Men had higher NAD overall, with a median of 19.91 µM compared with 17.43 µM in women.

Hypertension and cardiovascular disease tied to lower NAD

It was revealed that the pattern changed among the 243 participants with chronic disease. In men, NAD declined with age, and in women, the age-related increase seen in healthy participants disappeared. When the researchers looked at specific conditions, the drop was concentrated in cardiovascular disease and particularly hypertension, in both sexes. Dyslipidemia showed no reduction in either sex.

The lower levels held even though participants with chronic disease were taking medications, suggesting NAD stays low even in treated patients, the authors wrote. They added that because hypertension becomes more common with age, earlier studies that did not separate out people with cardiovascular disease may have mistaken a disease effect for an aging effect.

That age link is prevelant in the U.S. Nearly half (47.7%) of U.S. adults had hypertension in 2021 to 2023, with prevalence climbing from 23.4% among adults ages 18 to 39 to 71.6% among those 60 and older, according to the CDC’s National Center for Health Statistics. Only about 1 in 5 adults with hypertension had their blood pressure controlled.

What it means for NAD supplements

The 22 participants who reported taking NAD boosters had significantly higher levels than nonusers, and six of them (27%) reached 38 to 58 µM, roughly two to three times the range seen in people not taking supplements. In a small exploratory arm, two volunteers taking 1,000 mg of NMN daily saw NAD rise from about 19 to 20 µM to about 51 to 56 µM within days.

“The long-term consequences of sustained high NAD levels in the human body are unknown,” the authors wrote, noting that most trials last only weeks to months and are too small to detect rare or delayed effects. They pointed to early trials suggesting NAD-precursor supplements may lower systolic blood pressure and arterial stiffness in adults with hypertension, but said adequately powered trials and long-term safety data are needed.

The researchers also cautioned that the study was not designed to establish causality and should not be used to support NAD supplementation as a treatment for hypertension or cardiovascular disease. Because participants with chronic disease were on medication, the differences could reflect treatment rather than disease alone.

“Our data do not provide evidence for a universal whole-blood NAD deficit in healthy adults and therefore provide no broad rationale for NAD-boosting interventions,” the authors wrote.