Your blood vessels are lined with a thin layer of cells called the endothelium. One of the most important things that layer does, every day, without you noticing, is make a gas called nitric oxide.
What Nitric Oxide Actually Does
Nitric oxide is a molecule your blood vessels produce that helps them relax and widen, supporting healthy blood flow. When your endothelium senses the natural push of blood moving through it — what researchers call shear stress — it releases nitric oxide, which signals the muscle in your vessel walls to loosen up. Wider, more relaxed vessels mean blood moves more easily, which is a genuinely central part of how your cardiovascular system stays healthy.
This isn’t a fringe or speculative idea — nitric oxide’s role as a real signaling molecule in blood vessels is foundational, well-established physiology, not a marketing claim. (If you’ve heard of “nitrous oxide” from the dentist’s office — that’s a completely different substance. Nitric oxide is a molecule your own body makes; nitrous oxide is a separate gas used as an anesthetic. The similar names are a common source of confusion, not a connection.)
How Your Body Makes More of It
A few real, evidence-supported everyday habits help support this natural process:
Eating nitrate-rich vegetables. Beetroot, spinach, and other leafy greens are converted by your body — with help from certain bacteria in your mouth — into nitric oxide. Eating nitrate-rich vegetables may modestly help support healthy blood pressure for some people, typically when eaten regularly over time rather than as a one-time effect. See our full breakdown of the research for what a real, evidence-backed amount looks like.
Being mindful about oral care timing. Using antiseptic mouthwash regularly may reduce the blood-pressure benefit of eating nitrate-rich vegetables over time, since certain mouth bacteria help convert that nitrate into nitric oxide. This doesn’t mean skipping oral hygiene — it’s a real, if still-emerging, reason to be thoughtful about how often you reach for an antiseptic rinse. See our guide to oral care and nitric oxide for the fuller picture, including real controlled-trial evidence.
Nasal breathing and humming. Humming has been shown to increase nitric oxide levels in the nose by roughly 15 times compared to quiet breathing — an effect that shows up quickly, within the same session. This nasal-NO effect is local to the sinuses — it hasn’t been shown to raise nitric oxide throughout the body the way dietary nitrate does. It’s a small, real, low-effort habit, not a substitute for the food-based habits above. See our full explanation of humming and nasal nitric oxide for the details.
Movement and exercise. The same shear-stress signal that triggers nitric oxide release happens naturally during physical activity, which is part of why regular movement supports long-term vascular health.
A note on timing: these four habits don’t all work on the same timeline. Humming’s nasal effect is close to immediate; dietary nitrate’s blood-pressure benefit builds over sustained, regular intake — days to weeks, not a single meal; exercise’s benefit is cumulative, building with consistent practice over time. None of them is a quick fix, and none requires waiting indefinitely either.
What the Evidence Doesn’t Yet Support
Nitric oxide itself is a short-lived gas your body produces — supplements don’t contain nitric oxide directly; instead, they provide ingredients (like nitrate, L-arginine, or L-citrulline) your body can use to make more of it. See our food vs. supplement comparison for how these ingredients actually differ from each other. Claims that nitric oxide supplements can “detox” the body, reverse aging, or reliably treat chronic disease are not supported by current evidence. See our companion Myth-vs-Reality article for a closer look at what the supplement marketing gets wrong.
A Real Safety Note
If you take a nitrate medication (such as nitroglycerin), you should never combine it with erectile dysfunction medicines like sildenafil (Viagra) or tadalafil (Cialis) — the combination can cause a dangerous drop in blood pressure. Always follow your doctor’s or pharmacist’s guidance. Food-based sources of nitric oxide support (like L-arginine-containing foods) are a different safety category than prescription nitrate medications for this specific interaction — but anyone on erectile-dysfunction or heart medication should still check with a doctor before starting a new supplement. See our full guide to nitrate medications and drug interactions for the full explanation.
This specific medication interaction is the most acute danger, but it isn’t the only reason a doctor’s input matters before adding an actual nitric-oxide-related supplement (one containing ingredients like L-arginine or L-citrulline — not the food-based habits described above). Real clinical research has found that L-arginine supplementation specifically — not dietary nitrate, and not the body’s own natural nitric oxide production — may worsen outcomes for some people recovering from a recent heart attack, with the clearest research signal in older adults. Separately, L-arginine supplementation has not been shown to help, and in at least one study performed worse than a placebo, for people with peripheral artery disease. As with starting any new supplement, it’s also sensible to check with a doctor first if you’re pregnant or have kidney or liver disease — this is general, prudent practice rather than a nitric-oxide-specific finding. None of this changes the food-based habits described above, which sit in a different, well-evidenced category — but anyone actually considering a nitric-oxide-related supplement product should talk to a doctor first, especially in any of the situations above.
Where This Fits in the Bigger Picture
Nitric oxide isn’t a single silver-bullet fix — it’s one real, well-understood piece of how your cardiovascular system works day to day. The most evidence-supported way to support it is also the simplest: eat nitrate-rich vegetables regularly, be thoughtful about oral care timing, stay physically active, and be skeptical of supplement marketing that promises more than the evidence shows.
If blood pressure concerns or medication questions continue despite trying these routines, it’s worth talking with a doctor or other qualified professional.
References
- Tran, N., Garcia, T., Aniqa, M., Ali, S., Ally, A., & Nauli, S. M. (2022). Endothelial nitric oxide synthase (eNOS) and the cardiovascular system: in physiology and in disease states. American Journal of Biomedical Science and Research, 15(2), 153–177. https://pmc.ncbi.nlm.nih.gov/articles/PMC8774925/
- Norouzzadeh, M., Rashedi, M. H., Payandeh, N., Harijani, A. M., & Shahinfar, H. (2024). The effects of dietary nitrate on blood pressure and vascular health: An umbrella review and updated meta-analysis and meta-regression. Journal of Functional Foods, 114, 106082. https://doi.org/10.1016/j.jff.2024.106082
- Weitzberg, E., & Lundberg, J. O. N. (2002). Humming greatly increases nasal nitric oxide. American Journal of Respiratory and Critical Care Medicine, 166(2), 144–145. https://doi.org/10.1164/rccm.200202-138BC
- Chai, X., Liu, L., & Chen, F. (2024). Oral nitrate-reducing bacteria as potential probiotics for blood pressure homeostasis. Frontiers in Cardiovascular Medicine, 11, 1337281. https://doi.org/10.3389/fcvm.2024.1337281
- Schwartz, B. G., & Kloner, R. A. (2010). Drug interactions with phosphodiesterase-5 inhibitors used for the treatment of erectile dysfunction or pulmonary hypertension. Circulation, 122(1), 88–95. https://doi.org/10.1161/CIRCULATIONAHA.110.944603
- Kaynarkaya, B., Eren, Ş., & Şeker, E. N. (2026). Nitric oxide supplement: Evidence-based benefits, risks, and practical guidance. Acibadem International Health Library. Published July 19, 2026; medically reviewed July 17, 2026. https://acibademinternational.com/health-library/nitric-oxide-supplement-evidence-based-benefits-risks-and-practical-guidance/
- Schulman, S. P., Becker, L. C., Kass, D. A., et al. (2006). L-Arginine therapy in acute myocardial infarction: The Vascular Interaction With Age in Myocardial Infarction (VINTAGE MI) randomized clinical trial. JAMA, 295(1), 58–64. https://doi.org/10.1001/jama.295.1.58
- Wilson, A. M., Harada, R., Nair, N., Balasubramanian, N., & Cooke, J. P. (2007). L-arginine supplementation in peripheral arterial disease: no benefit and possible harm. Circulation, 116(2), 188–195. https://doi.org/10.1161/CIRCULATIONAHA.106.683656
About this article
Researched and written by: HealthUpward Editorial Team
Last updated: August 29, 2026
Evidence basis: Based on peer-reviewed research and reputable public health organizations cited within this article.
Medical review: This article has completed HealthUpward’s editorial review process. It has not been reviewed by a licensed healthcare professional.
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