What is Nitric Oxide?

What is Nitric Oxide?

Author: Shawn Woodman, Founder and Visionary, Nitrolithic Labs

This short post is a primer to inform the reader of a few of many functions of nitric oxide (NO) in human physiology. In exploring the basics of NO, we will only begin to scratch the surface. Future articles will cover individual subject areas in more detail.

NO is a simple molecule composed of nitrogen and oxygen. This molecule plays a crucial role in many essential processes in the human body. Nitric oxide is a relatively recent discovery. Most people aren’t aware of the importance of NO, presumably even many medical providers. It wasn't until 1986 that scientists discovered nitric oxide as a signaling molecule in mammalian tissue. In 1980, scientists set out to determine what causes the endothelium (smooth muscle cells lining blood vessels and arteries) to relax and regulate blood pressure. But what was the compound, hormone or chemical responsible for the action? They only knew this elusive substance as endothelium-derived relaxing factor (EDRF). For six years, scientists conducted research to identify EDRF. Finally, in 1986 Dr. Louis Ignarro and his team demonstrated that EDRF was nitric oxide.1

Nitric oxide is a gas that functions as a signaling molecule, transmitting messages between cells. NO is essential to many physiological processes, including blood pressure regulation, immune system function, erectile function, and neurotransmission to name a few. Tissue forms nitric oxide using a group of enzymes called nitric oxide synthases, and l-arginine, which are present throughout the body. NO only lasts for a very short period of time once released in tissue, one second or less, but in that span, it elicits an effect.2

Blood pressure regulation is one of nitric oxide's most well-known and critical functions. When the endothelium is stimulated, it releases nitric oxide. Nitric oxide signals the smooth muscle cells in the blood vessel walls to relax and increase blood flow. This process, known as vasodilation, helps to lower blood pressure and improve circulation. A study titled Mechanisms and Consequences of eNOS Dysfunction in Hypertension states, “It has become clear that nitric oxide (NO), produced by the endothelial isoform of NO synthase (eNOS) in the vascular endothelium, plays an important role in regulating blood pressure. Reduced NO bioavailability is a hallmark of endothelial dysfunction, and plays an important role in mediating blood pressure elevation.”3

NO also influences immune system function. Nitric oxide can kill bacteria and other microbes by damaging their DNA and proteins. According to a study titled, Protection against oral and gastrointestinal diseases: importance of dietary nitrate intake, oral nitrate reduction and enterosalivary nitrate circulation, “…studies showed that nitrate is converted to nitrite in the oral cavity that then ‘fuels’ an important mammalian resistance mechanism against infectious diseases.”4

Male and female erectile tissue depends on the presence of nitric oxide for sexual function. “NO plays an important role in the biology of the penis, especially for penile erection. Studies have found that NO causes muscle smooth muscle relaxation, which is the basis of an erection. In this process, NO synthase subtypes have different roles. nNOS initiates erectile response, eNOS promotes maximum erectile response.”5 Female genitalia contains almost as much erectile tissue as the penis. Many people don’t realize it, since the anatomy conceals the majority of it. Female erectile tissue depends on nitric oxide for engorgement and enhanced sensation the same as male erectile tissue. Additionally, NO is necessary in male and female reproductive processes. We will cover this in a future article.

Another important function of nitric oxide is neurotransmission, the communication between neurons in the brain. Nitric oxide acts as a neurotransmitter, transmitting signals between neurons and helping to regulate brain function. NO is necessary for learning, memory, and other cognitive processes. The subject of NO, the brain, and neurotransmission is a long and complex subject; and involves every system in the human body. The reader can do a deep dive into the subject in the following article, Nitric oxide signaling in the brain and its control of bodily functions. Abstract: “Nitric oxide (NO) is a versatile molecule that plays key roles in the development and survival of mammalian species by endowing brain neuronal networks with the ability to make continual adjustments to function in response to moment‐to‐moment changes in physiological input. Here, we summarize the progress in the field and argue that NO‐synthetizing neurons and NO signaling in the brain provide a core hub for integrating sensory‐ and homeostatic‐related cues, control key bodily functions, and provide a potential target for new therapeutic opportunities against several neuroendocrine and behavioral abnormalities.”7

The Nobel Prize Award-winning discovery. In 1998 Robert F. Furchgott, Louis J. Ignarro and Ferid Murad were jointly awarded the Nobel Prize in Physiology or Medicine "for their discoveries concerning nitric oxide as a signaling molecule in the cardiovascular system."6 Regarding the importance of the discovery of nitric oxide, Dr. Ignarro said, “The benefits to humankind are numerous, having been made in my laboratory and in other laboratories, and include cardiovascular function and health, brain function and health, digestive function, joint function, exercise endurance, erectile function, and many others.”8

There are two pathways for the body to produce NO. The first is through the endothelium. The endothelium generates NO from L-arginine. The second is from consuming dietary nitrates and nitrites. Green leafy vegetables and root vegetables such as beets provide nitrates. The body cannot produce NO from nitrates, so the digestive system and “good” bacteria located on the tongue and in the gut, break the nitrates down into nitrites for the body to use for NO production.

The first pathway (endothelial pathway) becomes less effective as a person ages. “We lose about 10-12 percent of our endothelial-produced NO per decade. In fact, by the time we are 40 years old, we have lost 50 percent of our ability to produce NO from endothelial cells.”9 When the first pathway becomes less efficient, the second pathway can help to make up the difference.

The second pathway, dietary, can also become compromised. Foremost, many Westerners do not consume enough nitrate-rich food to provide enough nitrates. Additionally, use of mouthwash, acid-reflux medication, and antibiotics can reduce the effectiveness of this pathway. More on this in a later article.

Nitrolithic LabsTM has developed a nitric oxide-boosting supplement called NitroVitalityTM that aims to increase NO production through every possible pathway, short of prescription medication. The formula contains l-citrulline and l-arginine to ensure that the body has the building blocks to make endogenous NO in the endothelium and other tissues. It contains high nitrate content beetroot juice to ensure that adequate dietary nitrates are available for the second pathway (digestive). It contains coenzymes to promote NO production and absorption. It contains l-theanine to promote focus and reduce social anxiety and performance anxiety (which may help with performance anxiety-induced erectile dysfunction, task focus, social situations, stress, blood pressure, workout focus, and insomnia.) NitroVitality is in the pre-launch phase. Please sign up for our email list and follow us on social media!

Order NitroVitality Now! https://www.nitrolithiclabs.com/

The author of this article is not a doctor, certified nutritionist, or any type of medical provider. The author has been studying nutritional supplements, health and fitness for over 25 years. As the founder and visionary of Nitrolithic Labs, the founder brings the vision for the company, the needs of our customers, the research and studies from doctors and scientists, and the expertise of formulators at certified supplement manufacturing partners together to create the best supplements on the market. Our aim is to help our customers on their journeys to optimize health, fitness and wellness!

The Site cannot and does not contain medical/health advice. The medical/health information provided is for general informational and educational purposes only and is not a substitute for professional advice. Before taking any actions based upon such information, we encourage you to consult with the appropriate professionals. We do not provide any kind of medical/health advice.10



  1. https://www.drignarro.com/the-history-of-the-discovery-of-nitric-oxide/
  2. https://www.drignarro.com/nitric-oxide-the-basics/
  3. Li Q, Youn JY, Cai H. Mechanisms and consequences of endothelial nitric oxide synthase dysfunction in hypertension. J Hypertens. 2015 Jun;33(6):1128-36. doi: 10.1097/HJH.0000000000000587. PMID: 25882860; PMCID: PMC4816601
  4. Duncan C, Li H, Dykhuizen R, Frazer R, Johnston P, MacKnight G, Smith L, Lamza K, McKenzie H, Batt L, Kelly D, Golden M, Benjamin N, Leifert C. Protection against oral and gastrointestinal diseases: importance of dietary nitrate intake, oral nitrate reduction and enterosalivary nitrate circulation. Comp Biochem Physiol A Physiol. 1997 Dec;118(4):939-48. doi: 10.1016/s0300-9629(97)00023-6. PMID: 9505412
  5. Luo Y, Zhu Y, Basang W, Wang X, Li C, Zhou X. Roles of Nitric Oxide in the Regulation of Reproduction: A Review. Front Endocrinol (Lausanne). 2021 Nov 19;12:752410. doi: 10.3389/fendo.2021.752410. PMID: 34867795; PMCID: PMC8640491
  6. https://www.nobelprize.org/prizes/medicine/1998/summary/
  7. Chachlaki K, Prevot V. Nitric oxide signalling in the brain and its control of bodily functions. Br J Pharmacol. 2020 Dec;177(24):5437-5458. doi: 10.1111/bph.14800. Epub 2019 Sep 8. PMID: 31347144; PMCID: PMC7707094. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7707094/
  8. https://www.drignarro.com/why-was-the-nobel-prize-awarded-for-nitric-oxide/
  9. Functional Nitric Oxide Nutrition: Dietary Strategies to Prevent and Treat Chronic Disease by Nathan S. Bryan PhD
  10. https://www.nitrolithiclabs.com/pages/disclaimers
  11. Image taken from https://www.drignarro.com/nitric-oxide-in-health-and-disease/
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