What is Nitric Oxide?

Nitric oxide is a colorless gas that is important in many processes in the body, including in the cardiovascular system. In 1986, researchers Robert Furchgott and Louis Ignarro discovered how nitric oxide relaxes and expands the blood vessels. Subsequently, people have increasingly used it to lower blood pressure and improve blood flow.

But how does that relaxing and widening process actually happen? So, where does NO come from, and how does your body use it?

Where Does Your Body Get Nitric Oxide?

There are a few major ways to increase nitric oxide (NO) in your body: physical exercise, L-arginine, and dietary nitrates.


One is through exercise. For example, do 20 jumping jacks or push-ups. This makes your heart pump more quickly and with more force. This increases blood flow. And when blood flow is increased, there is more friction against the inner lining of the blood vessel wall.

The innermost layer of your blood vessel wall is called the vascular endothelial wall. When you exercise and your blood flow increases, this layer is stimulated. It activates what is called the Nitric Oxide Synthase (NOS), an enzyme that causes NO to form. This is a quick and simple way to increase NO in your body, which is one of many good reasons to exercise regularly.


Baby spinach leaves

Another way your body gets NO is through l-arginine. This is an amino acid your body can produce, but you mainly get it from your diet. It is foods like spinach, lentils, soybeans, turkey, peanuts and pumpkin seeds. In addition, you can take it as a supplement.

Similar to when you exercise, when your vascular endothelial cells detect l-arginine, they will produce the enzyme NOS. In a process that involves other cofactors, NOS converts l-arginine to NO. Interestingly, another amino acid called l-citrulline is produced during the process. L-citrulline can be used by the NOS to make more NO.

Dietary Nitrates


Last but not least, your body can also get NO from dietary nitrates (NO3). Foods like beets, garlic, meat and poultry, dark chocolate, leafy greens, citrus fruits, watermelon, and nuts and seeds all have dietary nitrates. These are converted to nitrate (NO2) by bacteria in the mouth and stomach and then become nitric oxide (NO) through processes we are still trying to understand.

Main Points:

  • When you exercise, the inner wall cells of your blood vessels are stimulated and produce an enzyme called Nitric Oxide Synthase (NOS), which causes NO to form.
  • L-arginine causes the blood vessel’s inner wall cells to encourage the production of NOS. NOS, along with other cofactors, coverts L-arginine to NO.
  • You can also get NO through eating dietary nitrates, including beets. Your body breaks down and coverts dietary nitrates into NO.

What Does Nitric Oxide Do?

Nitric Oxide Causes Vasodilation

Nitric Oxide ExpansionVasodilation is the widening of the blood vessels, which NO is able to cause. To understand how, we have to understand more about the blood vessel wall.

We have already talked about the innermost layer of the blood vessel wall: the vascular endothelial wall (made of endothelial cells). You also need to know about the middle layer: the vascular smooth muscle.

After your body produces NO, it diffuses into vascular smooth cells. This stimulates an enzyme called guanlyl cyclase, which produces cGMP (cyclic guanosine monophosphate). In a mechanism that involves calcium ions, potassium ions, and other enzymes, cGMP makes the rings of the vascular smooth wall relax. With the ring relaxed, the blood vessel dilates. This is how your blood pressure is lowered. Your blood has more room to flow and isn’t beating so harshly against the blood vessel walls.

Nitric Oxide Reduces Blood Clots and Inflammation

Your body needs to able to form blood clots to help you heal when you get a cut. These are formed by what are called platelets. This is a necessary process, but too much of a good thing can become a bad one. For example, platelets can form blood clots in your blood vessels and restrict blood flow. NO stops platelets from sticking to the inner wall of your blood vessels.

Like platelets forming blood clots, inflammation is your body’s reaction to harm. Your body swells when it is fighting off foreign invaders or harmful bacteria. But chronic inflammation means chronic pain. NO inhibits white blood cells from attaching to blood vessel walls.

Main Points:

  • NO is diffused into the vascular smooth cells, which stimulates guanyly cyclase
  • Guanyly cyclase produces cGMP, which causes your vascular smooth wall to relax
  • With the blood vessel wall relaxed, vasodilation occurs
  • NO stops platelets from adhering to blood vessel walls, preventing blood clots
  • NO also stops white blood cells from sticking to blood vessel walls, reducing inflammation

How Can I Increase NO in My Body?

Nitric oxide is important to your cardiovascular health. Through chemical processes, it relaxes and widens your blood vessel wall. This causes vasodilation and can lower your blood pressure. It also can remove blood clots and reduce inflammation. You can increase your NO production through:

  • Exercise regularly.
  • Eating dietary nitrate in foods like beets, garlic, citrus fruits, nuts and seeds, watermelon and pomegranate and supplements like Heartbeet Complete!
  • Increasing l-arginine intake. Eat foods like spinach, meat and poultry, lentils, chickpeas, peanuts, and pumpkin seeds. Or you can take as a supplement.
  • Include l-citrulline in your diet. It is found it food like watermelon, legumes, meats, and nuts. Like l-arginine, it can be taken as a supplement.
  • Consume plenty of antioxidants. Antioxidants like vitamin C, vitamin E, and glutathione can help prevent the breakdown of NO.

By following these guidelines, you can lower your blood pressure and increase healthy blood flow to your heart.

Key Terms

Cyclic guanosine monophosphate (cGMP)

A molecule (specifically a cyclic nucleotide) that works as an intercellular messenger. cGMP is produced when nitric oxide (NO) diffuses into the vascular smooth muscle cells. It causes the vascular smooth muscle to relax.

Dietary nitrates (NO3)

Dietary nitrates are a chemical compound found in foods such as beets, garlic, meat and poultry, dark chocolate, leafy greens, citrus fruits, watermelon, and nuts and seed. NO3 eventually converts to nitric oxide (NO) in the body.

Guanyly cyclase

An enzyme that is produced when NO reaches the vascular smooth cells. It, in turn, produces cGMP.


An amino acid you mainly get from your diet that is important in building proteins. L-arginine is converted by Nitric Oxide Synthase (NOS) and other cofactors into nitric oxide.


An amino acid that plays a role in building protein and encourages the production of NOS in the body, which produces nitric oxide. It is also released during the conversion of l-arginine into NO.

Nitric oxide (NO)

Nitric oxide is a free radical molecule (meaning it has an unpaired electron). It is a clear gas that is important in many physiological processes in the body, including in the cardiovascular system. When NO is introduced to the vascular smooth muscle (the middle layer of your blood vessel wall) it causes a chain reaction that makes the blood vessels relax and widen.

Nitric Oxide Synthase (NOS)

An enzyme produced by the vascular endothelial cells (the cells of the inner blood vessel wall). NOS, along with other molecules called cofactors, converts L-arginine into nitric oxide.


A small colorless disk-shaped cell fragment without a nucleus, found in large numbers in blood and involved in clotting. NO inhibits platelets from attaching to blood vessel walls.

Vascular endothelial wall

The inner layer of the blood vessel wall. It is important in the production of NO because it is stimulated by exercise and can detect l-arginine in the blood (causing NOS to form).

Vascular smooth muscle

The middle layer of the blood vessel wall. When NO reaches the vascular smooth muscle, it relaxes and causes the blood vessel to widen. This lowers the heart rate and increases blood flow.


The process in which the blood vessel relaxes and expands.