NMN and Blood Pressure: What 10 RCTs Actually Found

NMN can lower blood pressure a little. That is the cleanest reading of the first meta-analysis built specifically around this question—and it is a much narrower claim than the longevity-supplement hype machine prefers.

Across 10 randomized controlled trials with 11 intervention arms and 349 total participants, NMN reduced diastolic blood pressure by an average of 2.15 mmHg versus control. The 95% confidence interval ran from −3.68 to −0.61 mmHg, so the pooled result was statistically significant. Systolic pressure did not fall significantly across all participants. In adults aged 60 or older, however, the subgroup analysis found a statistically significant systolic reduction of 3.94 mmHg (95% CI, −7.06 to −0.82). Those results come from Zhang et al.'s 2026 systematic review and meta-analysis.

The result is worth knowing if you already take NMN. It is not a reason to treat NMN as an antihypertensive drug, skip exercise, or build a blood-pressure protocol around a supplement with fewer total trial participants than one arm of many drug trials.

What the meta-analysis found

Zhang and colleagues pooled randomized trials of nicotinamide mononucleotide, or NMN, a precursor to NAD+. The analysis used a common-effects model and prespecified subgroup analyses by dose, age, BMI, geography, intervention duration, and baseline blood pressure.

The headline result was diastolic blood pressure: a weighted mean difference of −2.15 mmHg. Diastolic pressure is the lower number on a blood-pressure reading, measured while the heart relaxes between beats. The confidence interval excluded zero, which means the pooled estimate met the conventional threshold for statistical significance.

For systolic blood pressure—the top number and usually the more important treatment target in older adults—the full pooled analysis was null. That distinction matters. You cannot turn a statistically significant diastolic result into evidence that NMN broadly lowers both numbers.

The age analysis offers a plausible exception. Participants aged 60 and older had a systolic reduction of 3.94 mmHg, with a 95% confidence interval of −7.06 to −0.82 mmHg. This result was statistically significant, but the interval is wide. The true effect compatible with these data ranges from modest to meaningfully larger, and a small evidence base makes subgroup findings especially fragile.

NMN has crossed the line from a purely theoretical blood-pressure idea to a statistically observed signal in pooled human trials. It has not crossed the line into established blood-pressure treatment.

How large is a 2 to 4 mmHg change?

Small changes in blood pressure can matter across populations, but statistical significance and clinical usefulness are different questions. A 2.15 mmHg fall in diastolic pressure is measurable. It is also too small to justify replacing standard blood-pressure care or treating NMN as a first-line intervention.

For perspective, a 2024 meta-analysis of aerobic-exercise trials in postmenopausal women reported systolic reductions of roughly 3 to 5 mmHg in cardiometabolic populations. A 2025 meta-analysis of Mediterranean-diet trials in type 2 diabetes also found lower systolic pressure. These comparisons do not prove that NMN cannot help. They establish the order of operations: exercise and dietary pattern changes have much broader cardiovascular evidence and should come first.

The older-adult systolic estimate for NMN sits in the same rough numerical neighborhood as some lifestyle effects, but that does not make the evidence comparable. The NMN estimate comes from 349 total participants across the entire meta-analysis, not 349 older adults followed for years.

Why older adults might respond more

The age-specific systolic finding has a biological rationale. NAD+ levels tend to fall with age, while CD38, an enzyme that consumes NAD+, rises. In a 2023 mechanistic study by Qiu et al., CD38 upregulation contributed to NAD+ depletion, higher blood pressure, and vascular damage. This evidence supports an age-related substrate-depletion model; it does not prove that oral NMN will correct hypertension in older people.

Another 2022 study of vascular aging found that age-related weakening of NPRA/PKG/AMPK signaling promoted vascular aging and elevated blood pressure. The pathway intersects with NAD+ and sirtuin biology at AMPK and offers another reason an older vascular system might have more room to respond. These are mechanistic findings, not clinical NMN blood-pressure trials.

The proposed chain is reasonable: NMN raises NAD+, NAD+ supports sirtuin activity, and SIRT1 can increase endothelial nitric oxide synthase activity. More nitric oxide can relax blood vessels and reduce resistance. A review of sirtuin biology in cardiovascular disease describes this NAD+-SIRT1-eNOS-nitric-oxide pathway. Biology, however, is a map, not a clinical outcome.

What human studies establish—and what they do not

Human evidence confirms that oral NMN can raise NAD+ status. In a double-blind, placebo-controlled trial of 25 prediabetic women, Yoshino et al. found that NMN increased muscle NAD+ about 1.25-fold above baseline. Blood pressure was not an endpoint, so the study establishes bioavailability rather than a blood-pressure effect.

A more informative bridge came from Katayoshi et al.'s 2023 double-blind, placebo-controlled trial. The researchers measured NAD+ metabolism and arterial stiffness after long-term NMN supplementation, finding that oral NMN raised circulating NAD+ and linked that increase to changes in vascular compliance. Arterial stiffness is relevant to blood pressure, especially systolic pressure with aging, but it remains a vascular surrogate rather than proof of fewer heart attacks, strokes, or medication needs.

The broader meta-analysis did not measure NAD+ alongside blood pressure in most included trials. As a result, it cannot show that participants whose blood pressure changed were the same participants whose NAD+ rose, nor can it confirm that NAD+ repletion caused the blood-pressure result.

Why the evidence still needs restraint

• The clinical sample is small. Ten RCTs and 349 participants leave limited room to assess uncommon harms, precise effect sizes, or who benefits most.
• The dose question remains unanswered. The meta-analysis examined dose subgroups, but published results do not identify whether 250 mg, 500 mg, or at least 1,000 mg per day drove the effect. More is not an evidence-based strategy.
• Baseline blood pressure is unresolved. The trials likely included both normotensive and hypertensive participants. The available results do not clarify whether benefits concentrate in people with elevated baseline pressure or those taking antihypertensive medication.
• Duration was short. Individual trials likely lasted 8 to 16 weeks, and no blood-pressure outcome data extend beyond six months.
• Heterogeneity and publication bias remain unclear. The common-effects model assumes similar effects across trials, while available abstract data do not report I² statistics or formal publication-bias assessments such as Egger's test.
• The older-adult result needs replication. It may reflect a real age interaction, insufficient power in the overall analysis, or a post-hoc subgroup result. Biological plausibility helps explain a finding; it does not validate it.

The practical verdict

If you are under 60 with normal or mildly elevated blood pressure, the current evidence does not support taking NMN primarily to lower it. The overall systolic result was non-significant, and the average diastolic effect was small.

If you are 60 or older and already use NMN for another reason, the systolic subgroup result mildly supports the possibility of a blood-pressure bonus. Check your pressure with a validated home monitor, keep prescribed treatment in place, and judge the supplement against real readings rather than a hopeful mechanism diagram.

NMN now has a credible, modest pooled blood-pressure signal. The next useful trial would enroll enough older adults with elevated baseline pressure, measure NAD+ and vascular outcomes alongside blood pressure, test clearly defined doses, and last longer than a few months. Until then, NMN belongs behind exercise, dietary change, and standard medical care—not in front of them.