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Nitric Oxide and Blood Flow: How This Molecule Keeps Your Arteries Healthy

The tiny gas behind relaxed, healthy blood vessels.

Quick answer

Nitric oxide (NO) is a gas made by the endothelium, the inner lining of blood vessels, from the amino acid L-arginine. It signals the muscle in artery walls to relax, widening the vessels, which supports healthy blood flow and blood pressure. Nitric oxide production tends to decline with age, inactivity, smoking and oxidative stress. You can support healthy nitric oxide levels by eating nitrate-rich vegetables such as beets, spinach and arugula, exercising regularly, not smoking, and getting enough L-citrulline, which the body converts to L-arginine more efficiently than arginine taken by mouth.

Key takeaways

The discovery of nitric oxide's role in the cardiovascular system earned the 1998 Nobel Prize in Physiology or Medicine. Here's why it matters for your circulation.

How nitric oxide works

Made in the artery lining

Endothelial cells use an enzyme called eNOS to turn L-arginine into nitric oxide.

Relaxes the vessel wall

Nitric oxide diffuses into the smooth muscle of the artery wall, causing it to relax and the vessel to widen.

Keeps vessels healthy

It also helps keep the vessel lining smooth and supports healthy blood cell flow.

Two pathways to nitric oxide

PathwaySourceHow to support it
Arginine pathwayL-arginine (from L-citrulline)Protein foods, watermelon, L-citrulline
Nitrate pathwayDietary nitratesBeets, spinach, arugula, celery

Why L-citrulline?

Much of the L-arginine you swallow is broken down in the gut and liver before it reaches the bloodstream. L-citrulline avoids this, and the kidneys convert it into L-arginine, which is why studies have found citrulline raises arginine levels more effectively. Vasoryn includes L-citrulline alongside pine bark and grape skin antioxidants that help protect the endothelium.

Caution: nitric oxide supporting supplements may add to the effect of blood pressure medicines, nitrates (such as nitroglycerin) and erectile dysfunction drugs. Talk to your doctor first if you take any of these.

Sources

  1. Nobel Prize Outreach – "The Nobel Prize in Physiology or Medicine 1998: Furchgott, Ignarro, Murad."
  2. Schwedhelm E. et al. – "Pharmacokinetic and pharmacodynamic properties of oral L-citrulline and L-arginine," British Journal of Clinical Pharmacology, 2008.
  3. Lundberg J.O. et al. – "The nitrate-nitrite-nitric oxide pathway in physiology and therapeutics," Nature Reviews Drug Discovery, 2008.

Common questions

What does nitric oxide do?

It signals blood vessels to relax and widen, supporting healthy blood flow.

How can I increase nitric oxide naturally?

Eat nitrate-rich vegetables, exercise regularly and avoid smoking.

Is L-citrulline better than L-arginine?

Studies show oral L-citrulline raises blood arginine levels more effectively.

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