Cardiovascular disease remains the leading cause of death in most high-income countries, and its primary drivers — arterial stiffening, endothelial dysfunction, cardiac hypertrophy, and atherosclerosis — are fundamentally processes of biological aging rather than inevitable consequences of bad luck or bad genes. NAD+ connects to cardiovascular aging through several specific mechanisms, and the human clinical evidence in this domain is among the most developed of any NAD+ application area — largely because arterial stiffness and blood pressure can be measured precisely in clinical trials, providing clean endpoints that are difficult to obtain for more diffuse outcomes like “healthier aging.”
This article maps NAD+’s specific roles in cardiovascular tissue, reviews the human evidence on NAD+ precursor supplementation and cardiovascular outcomes, and places that evidence in the context of the broader cardiovascular aging landscape.
The Cardiovascular System and Biological Aging
The heart and blood vessels age in characteristic ways that are mechanistically distinct from chronological time passing. Arterial walls progressively stiffen as elastin fibers degrade and cross-linked collagen accumulates, reducing the Windkessel effect — the elastic buffering of pulse pressure that protects downstream microcirculation. Endothelial cells lining the vessels become less responsive to nitric oxide signaling, impairing vasodilation. Cardiac muscle cells (cardiomyocytes) — largely post-mitotic like neurons — accumulate mitochondrial damage and reduce their contractile efficiency. And chronic low-grade inflammation promotes the foam cell formation and oxidative modification of LDL that underlies atherosclerotic plaque development.
Each of these processes has a NAD+-dependent dimension. Understanding them specifically is more useful than the general claim that “NAD+ supports heart health” — which is accurate but does not convey the mechanistic specificity that justifies the interest.
NAD+ and Arterial Stiffness: The Most Developed Human Evidence
Aortic stiffness — measured as pulse wave velocity (PWV), the speed at which a pressure wave travels through the arterial tree — is one of the most important cardiovascular biomarkers in aging research. Higher aortic stiffness independently predicts cardiovascular events, cardiac failure, cognitive decline, and all-cause mortality. It is both a consequence of vascular aging and a driver of further damage, because stiffer arteries transmit higher pulse pressures to the heart and to small vessels in the brain and kidneys.
The best human evidence for NAD+ precursors and cardiovascular outcomes comes from the Martens et al. (2018) trial published in Nature Communications. This randomized, double-blind, crossover trial gave 24 healthy older adults NR at 1,000 mg/day or placebo for six weeks in each arm. The key cardiovascular finding: in participants with elevated systolic blood pressure at baseline (above 120 mmHg), NR significantly reduced aortic stiffness (as measured by PWV) and systolic blood pressure. Participants with normal blood pressure showed no significant change.
This population-specific effect pattern — improvement in people with elevated baseline values, no change in those already in the normal range — is the signature of an intervention that corrects dysfunction rather than pushing a healthy system further in one direction. It is the same pattern seen with berberine and blood glucose, and it is mechanistically appropriate: restoring NAD+ in a system already functioning normally provides less marginal benefit than restoring it where NAD+-dependent processes are impaired.
The magnitude of the arterial stiffness reduction in the Martens trial was clinically meaningful — the reduction in PWV was comparable in magnitude to that achieved by some antihypertensive drug classes in similar populations. For a supplement trial, this is a notable effect size.
The mechanistic explanation involves SIRT1-mediated regulation of arterial wall biology. SIRT1 is expressed in vascular smooth muscle cells and endothelial cells, where it suppresses the profibrotic and pro-inflammatory gene programs that drive arterial wall stiffening. As NAD+ declines and SIRT1 activity falls in vascular tissue, these programs are derepressed — contributing to increased collagen cross-linking and reduced elastin preservation in the arterial wall. Restoring NAD+ and SIRT1 activity does not reverse existing collagen cross-links, but it may slow the ongoing process of arterial wall remodeling that drives progressive stiffening.
Endothelial Function and Nitric Oxide
The endothelium — the single cell layer lining the interior of blood vessels — is one of the most metabolically active tissues in the body and one of the earliest sites of cardiovascular aging. Endothelial cells produce nitric oxide (NO) through endothelial nitric oxide synthase (eNOS), which is the primary signal for vascular smooth muscle relaxation and vasodilation. Impaired endothelial NO production is an early and central feature of cardiovascular disease and vascular aging.
NAD+ connects to endothelial function through SIRT1, which deacetylates and activates eNOS — directly increasing NO production capacity. As NAD+ declines and SIRT1 activity falls in aged endothelium, eNOS is more heavily acetylated and less active, reducing NO bioavailability and impairing vasodilation. This mechanism provides a specific path from NAD+ decline to endothelial dysfunction that is independent of, and additive to, the oxidative stress-driven NO depletion that also characterizes aged vessels.
SIRT1 also suppresses NF-κB in endothelial cells, reducing the expression of adhesion molecules (VCAM-1, ICAM-1) that promote monocyte attachment to the vessel wall — an early step in atherosclerotic plaque formation. This anti-atherogenic effect of SIRT1 activation connects NAD+ availability to one of the primary mechanisms of cardiovascular disease beyond stiffness and hypertension.
Cardiac Function: SIRT3 and Mitochondrial Health in the Heart
The heart is one of the most mitochondria-dense tissues in the body — cardiomyocytes contain mitochondria that occupy approximately 30% of cell volume, reflecting the extraordinary and continuous ATP demand of cardiac muscle. This mitochondrial density makes the heart particularly sensitive to the NAD+-dependent mitochondrial maintenance processes regulated by SIRT3.
SIRT3 deacetylates and activates multiple mitochondrial proteins in cardiomyocytes: components of the electron transport chain, enzymes in the citric acid cycle, and SOD2 (the primary mitochondrial antioxidant). As NAD+ declines and SIRT3 activity falls with age, these cardiac mitochondrial proteins become hyperacetylated and less active, mitochondrial efficiency decreases, and oxidative stress in cardiomyocytes increases.
In animal models, SIRT3 knockout accelerates cardiac hypertrophy and failure under stress conditions, while SIRT3 overexpression is protective. The NAD+-SIRT3 axis appears to be a genuine regulator of cardiac mitochondrial quality whose declining activity contributes to the age-related changes in cardiac performance that precede clinical heart failure.
The broader context for mitochondrial aging in the heart and other tissues is covered in the article on mitochondria and aging.
NAD+ and Cardiac Hypertrophy
Cardiac hypertrophy — the thickening of the heart wall that occurs in response to chronic pressure overload from hypertension — is a major risk factor for cardiac failure. It is also a process in which NAD+ and SIRT1/SIRT3 play regulatory roles that have been extensively studied in animal models.
Hypertrophic stimuli activate histone acetyltransferases (HATs) in cardiomyocytes, increasing histone acetylation and driving the hypertrophic gene program. SIRT1 and SIRT2 counteract this by deacetylating histones and the transcription factors that promote hypertrophic gene expression. In mouse models, NAD+ precursor supplementation or SIRT activation attenuates pathological cardiac hypertrophy — findings consistent with the mechanistic picture but not yet translated to definitive human clinical evidence.
A study by Diguet et al. (2018) in Circulation demonstrated that NR supplementation prevented cardiac hypertrophy and dysfunction in a mouse model of hypertension-induced heart failure, with significant mitochondrial improvements in cardiac tissue. This is animal data, but the model (pressure overload-induced hypertrophy) is directly relevant to the hypertensive cardiovascular aging that is common in the target demographic for NAD+ supplementation.
The CD38 Connection: Immune Activation and NAD+ in the Heart
CD38 — the primary NAD+-consuming enzyme responsible for much of the age-related NAD+ decline — is expressed in cardiac tissue and is significantly upregulated in response to cardiac stress and inflammation. In conditions of cardiac ischemia, heart failure, or chronic hypertensive stress, CD38 activity increases, depleting cardiac NAD+ and impairing the SIRT3 and SIRT1 activity that the heart depends on for mitochondrial maintenance. This creates a pathological cycle in which cardiac stress depletes NAD+, reduced NAD+ impairs mitochondrial function and stress response, and worsened mitochondrial function amplifies the cardiac damage.
The complete picture of how CD38 drives NAD+ depletion in aging and disease is covered in the article on the CD38 problem: why NAD+ gets depleted faster as you age. The cardiac implications are particularly relevant for people with existing cardiovascular risk factors, where CD38-mediated NAD+ depletion in the heart may be more severe than in metabolically healthy individuals.
Human Evidence Beyond the Martens Trial
The Martens et al. NR trial is the most rigorous human evidence for cardiovascular benefits from NAD+ precursor supplementation, but several other findings in the human literature add texture to the picture.
Liao et al. (2021) in Frontiers in Aging found that 250 mg/day NMN for 12 weeks reduced arterial stiffness in middle-aged adults with mildly elevated baseline stiffness — an NMN-specific parallel to the Martens NR finding that suggests the cardiovascular effect may be a class property of NAD+ precursors rather than NR-specific.
Morita et al. (2022) found improvements in endothelial function markers in middle-aged adults on NMN, consistent with the eNOS activation mechanism described above. These are preliminary findings from small trials but they are consistent with each other and with the mechanistic prediction.
A meta-analysis by Dollerup et al. examining blood pressure effects across NR trials found a trend toward blood pressure reduction that did not reach statistical significance in the pooled analysis — a result consistent with the Martens finding that effects are most pronounced in people with elevated baseline values, which when averaged with normotensive participants dilutes the signal.
Cardiovascular Applications in a Longevity Stack
For people with cardiovascular risk factors — elevated blood pressure, arterial stiffness, suboptimal lipid profiles, or metabolic syndrome — the cardiovascular evidence provides specific and actionable rationale for NAD+ precursor supplementation beyond the general longevity arguments. The Martens effect size at 1,000 mg/day NR in people with elevated systolic blood pressure is clinically meaningful and is achieved through a mechanism entirely distinct from antihypertensive medications, making it potentially complementary rather than redundant with pharmacological treatment.
The other compounds most relevant to cardiovascular aging in a longevity stack include vitamin K2 — which activates Matrix Gla Protein to prevent arterial calcification — and omega-3 fatty acids for triglyceride reduction and anti-inflammatory coverage. These are covered in the articles on vitamin D3 + K2 and in the advanced longevity stack article at the advanced longevity stack.
Anyone managing cardiovascular conditions with prescription medications should discuss NAD+ precursor supplementation with their cardiologist or prescribing physician before adding it to their regimen. NAD+ precursors are not cardiovascular drugs and do not replace established therapies, but their mechanisms are real and their potential interactions with medications warrant professional awareness.
Frequently Asked Questions
How long does it take for NMN or NR to affect blood pressure or arterial stiffness?
The Martens trial showed significant arterial stiffness and blood pressure reductions after six weeks of NR supplementation at 1,000 mg/day. The Liao NMN trial showed arterial stiffness changes over 12 weeks. These timescales are consistent with interventions that work through gene expression and protein modification rather than acute pharmacological effects — weeks rather than days. Individual responses will vary, and the magnitude of benefit is greatest in people with elevated baseline values.
Is the cardiovascular evidence strong enough to justify NMN or NR for heart health specifically?
The evidence is meaningful but not definitive. The Martens trial is well-designed and its finding of reduced arterial stiffness in people with elevated baseline values is a clinically relevant result. The NMN trials are smaller and more preliminary. The human evidence is not yet at the level of a large phase III trial establishing cardiovascular event reduction, which is the standard for cardiovascular drug approval. For someone with elevated arterial stiffness or blood pressure alongside a general interest in longevity supplementation, the cardiovascular evidence adds specific mechanistic justification to an already reasonable choice. For someone without cardiovascular risk factors, the general longevity rationale is the primary argument.
Does NAD+ supplementation interact with heart medications?
No specific serious interactions between NAD+ precursors and common cardiovascular medications have been established in human trials. NMN and NR inhibit certain cytochrome P450 enzymes to some degree, which could theoretically affect metabolism of drugs processed by those pathways — some statins and certain antiarrhythmics are processed by CYP3A4. For anyone on cardiovascular medications, discussing the addition of any supplement with the prescribing physician is prudent, even when no specific interaction is known. This is practical advice rather than a contraindication.
Can NAD+ supplementation help someone who has already had a heart attack?
Post-myocardial infarction cardiac remodeling involves significant NAD+ depletion through CD38 upregulation and PARP activation from ischemic DNA damage. The mechanistic argument for NAD+ precursor supplementation supporting cardiac recovery is coherent — SIRT3 activation could support mitochondrial recovery in post-ischemic cardiomyocytes, and SIRT1 activation could reduce the pro-fibrotic remodeling that impairs cardiac function after infarction. However, clinical trial evidence specifically in post-myocardial infarction patients is very limited, and this is a medical context where supplementation decisions should involve the treating cardiologist rather than self-direction.