4/1/20174 min read



Nitric oxide (NO), or more correctly nitric oxide monoxide, is an endogenous mediator of particularly important processes, such as vasodilation and transmission of nerve impulses. In nature, it is present as a colorless gas, particularly polluting, and with a density similar to that of air.

In our body, the synthesis of this compound is carried out by a group of enzymes belonging to the nitric oxide synthase (NOS) family, which use arginine as a substrate, an essential amino acid in children and conditionally essential in adults.

The synthesis of nitric oxide is stimulated by various factors such as shear stress, a parameter that measures the force exerted by blood flow on the walls of blood vessels. When blood pressure increases excessively, the body defends itself by synthesizing nitric oxide, which dilates the blood vessel walls and contributes to lowering blood pressure. On the contrary, inhibition of nitric oxide synthesis leads to an increase in peripheral resistance and a consequent increase in blood pressure.

Hormones such as noradrenaline and cytokines (proteins secreted during the immune response) also promote the synthesis of nitric oxide by the endothelium.

Main functions of nitric oxide:




- STIMULATES MITOCHONDIOGENESIS, the synthesis of new mitochondria.

The synthesis of nitric oxide is hindered by TNF-alpha, which is significantly higher in obese individuals compared to normal weight. In obese individuals, mitochondrial activity is greatly reduced, so what is eaten - not being adequately metabolized by mitochondria - is more easily stored as fat. This, in turn, releases large amounts of TNF-alpha, which in turn "kills" mitochondria. Additionally, the ATP deficiency due to reduced mitochondrial activity is perceived by the brain as a need for food.

Unlike excesses, calorie restriction is able to activate the expression of eNOS, stimulating mitocondriogenesis; the same applies to physical exercise.

Nitric oxide also has noteworthy therapeutic potential:

- Reduces blood pressure

- Enhances immune defenses

- Prevents angina, stroke, and heart attack

- Treats erectile dysfunction

In sports, the most favorable effect is promoting vasodilation.

Vasodilation refers to an increase in the caliber of blood vessels resulting from the relaxation of the smooth muscle of blood vessels, particularly arteries, and large veins. As a direct consequence, we have an increase in the lumen of blood vessels and, especially for arteries, a decrease in blood pressure.

The vasodilation induced by nitric oxide promotes an improvement in athletic performance due to increased blood supply, oxygen, and nutrients to tissues involved in exertion.

During physical activity, we observe an increase in blood pressure due to increased demand for oxygen and nutrients in the muscles. Vasodilation processes, therefore, ensure the same quantity of molecules required at the same pressure. But this is not the only beneficial aspect since in lactic anaerobic sports, the body must also deal with the need to eliminate produced lactic acid; an increase in the lumen of blood vessels allows this mechanism to be carried out more effectively.

Therefore, we can summarize the benefits of vasodilation as follows:

1. Increased aerobic performance due to increased oxygen supply.

2. Increased anaerobic performance due to increased rate of lactic acid disposal.

3. Increased overall performance and recovery due to increased nutrient supply.


Supplements that contribute to the production of nitric oxide:

Arginine? No, someone is trying to deceive you by selling you "the pumping amino acid" that is useless!

Arginine supplementation is not very effective because an intestinal enzyme (arginase) limits its absorption, worsening the price-benefits ratio even more (consuming more would cause diarrhea).

To bypass this problem, the solution is:


Citrulline can be converted to arginine as it acts as its precursor in the urea cycle, but it is not eliminated by any enzymes when taken orally as a supplement, completely replacing all the beneficial effects of arginine supplementation along with those derived from massive stimulation of nitric oxide. To enjoy the benefits of arginine supplementation, arginine is not needed, citrulline is! It is an intermediate metabolite of the urea cycle. NO synthases synthesize nitric oxide from arginine and oxygen. The first is initially transformed into citrulline, so what are the effects of citrulline supplementation? It is not surprising that there is an increase in nitric oxide. This is seen in several studies where both the L-form and the malate form are used. The recommended dosage in this case is 4-6 grams pre-workout.


Vitamin C and E, as antioxidants, help attenuate oxidative damage to NOS (nitric oxide synthase), indirectly allowing for better functioning. For the dosage in these cases, I would stick to 2 grams/day of vitamin C divided into small doses throughout the day and 15 mg (22.4IU approx.) for vitamin E. These are not specific supplements for vasodilation but they can indirectly help.

Coenzyme Q10

A new study on human endothelial cells provides an accurate assessment of the biological action of Q10.

It has been found that Q10 prevents the cascade of free radicals associated with LDL cholesterol, lowering iNOS (a macrophage mechanism for producing free radicals), and directly strengthening eNOS (mitocondriogenesis). Q10 blocks the activation of the basic signal of inflammatory gene activity known as NF-kB, preventing the production of molecules that form plaques in the arteries. This also indicates that Q10 is useful for heart health, artery health, and indirectly in the production of nitric oxide.


Are there foods that promote the production of nitric oxide? Absolutely!

Here are the main ones rich in nitrates:

Watermelon (in Latin "citrullus," hence the name of the metabolite citrulline), egg yolk, arugula, spinach, dark chocolate, beetroot, rhubarb, pomegranate, walnuts, blueberries, garlic, pistachios, salmon, liver, offal, shrimp.

However, we must not forget the inherent negative effects of the strong oxidizing action of this molecule. The cytotoxic effects of nitric oxide are comparable to those induced by other oxidizing agents that can significantly increase the production of free radicals (smoking, alcohol, drugs, ultraviolet rays, and ionizing radiation). It should be noted that excessive free radicals are currently considered one of the most dangerous allies of premature aging, degenerative diseases, and some forms of cancer.

This simple consideration should at least make those who paint nitric oxide as a miraculous substance reflect. The beneficial action of nitric oxide should be put into perspective, and supplementation should only be used if necessary for certain conditions or during periods of intense training as a pre-workout supplement.