Nitric oxide is produced by almost all types of cells in the human body and one of the most important molecules for the health of blood vessels.
It is a vasodilator, which means that it relaxes the internal muscles of the blood vessels, causing the vessels to widen. In this way, nitric oxide increases blood flow and lowers blood pressure.
Supplements that increase nitric oxide in the body are one of the most popular supplement categories today.
These supplements do not contain nitric oxide itself. However, they contain compounds that your body can use to produce nitric oxide and have been shown to provide many benefits for health and performance.
Here are 5 health and performance benefits of taking nitric oxide supplements.
1. Helps to treat erectile dysfunction
Erectile dysfunction (ED) is the inability to achieve or maintain an erection firm enough to have sex (1).
L-citrulline is an amino acid that can help treat erectile dysfunction by increasing the production of nitric oxide (2).
Nitric oxide is necessary for the muscles of the penis to relax. This relaxation allows the inner chambers of the penis to fill with blood so that the penis is erect (3).
In one study, it was discovered that L-citrulline improves erection hardness in 12 men with mild erectile dysfunction (4).
The researchers concluded that L-citrulline was less effective than prescription medications used to treat ED, such as Viagra. However, L-citrulline proved to be safe and well tolerated.
It has been shown that two other supplements that stimulate nitric oxide treat erectile dysfunction: the amino acid L-arginine and Pycnogenol, a plant extract of pine.
In several studies, a combination of L-arginine and Pycnogenol significantly improved sexual function in men with ED (5, 6, 7, 8).
When taken together, L-arginine and Pycnogenol also appear safe (9).
Summary Nitric oxide plays an important role in erectile function. It has been shown that several supplements, including L-citrulline, L-arginine and Pycnogenol, increase the levels of nitric oxide in men with erectile dysfunction (ED).
2. Can reduce muscle pain
A form of L-citrulline called citrulline malate not only increases the production of nitric oxide, but also decreases muscle pain.
Muscle pain is an uncomfortable experience that tends to occur after strenuous or unaccustomed exercise (10).
This pain is called late-onset muscle pain and usually feels stronger 24 to 72 hours after exercise.
In one study, 41 people were randomly assigned to receive 8 grams of citrulline malate or a placebo one hour before performing as many repetitions as possible on a flat bar bench press (11).
Those who received citrulline malate reported 40% less muscle pain at 24 and 48 hours after exercise, compared to those who took the placebo.
Citrulline malate increases the production of nitric oxide, which increases the blood flow to the active muscles. In turn, it is thought that citrulline malate increases the supply of nutrients and eliminates waste products related to muscle fatigue, such as lactate and ammonia (12).
However, a later study on the effects of citrulline after leg exercises did not find citrulline malate to be useful for the treatment of muscle pain (13).
One explanation for this difference in the findings is that people in the leg exercise study were given 6 grams of citrulline malate, which is 2 grams less than the previous study.
Therefore, the ability of citrulline malate to decrease muscle pain may depend on the dose and exercise. However, more research is needed on this.
Summary Citrulline malate is a form of L-citrulline that can help relieve muscle pain by increasing nitric oxide. The dose and type of exercise can affect the ability of citrulline malate to decrease muscle pain.
3. Lower blood pressure
It is thought that people with high blood pressure have a limited ability to use nitric oxide in their bodies (14, 15).
High blood pressure occurs when the force of blood pushing against the walls of the arteries is too high.
Over time, high blood pressure can lead to health problems such as heart and kidney disease.
It has been shown that a diet high in fruits and vegetables lowers blood pressure and, therefore, reduces the risk of disease (16).
This has led researchers to test the beneficial effects of certain compounds found in fruits and vegetables on blood pressure levels.
Nitrate is a compound found in beets and dark green leaves such as spinach and arugula.
When you consume nitrate, your body converts it into nitric oxide, which in turn causes the blood vessels to relax and dilate, lowering blood pressure.
Many studies have shown that nitrate can help lower blood pressure by increasing the production of nitric oxide (17, 18, 19, 20).
One review analyzed the effects of taking nitrate supplements on blood pressure in adults (21).
Of the 13 studies analyzed, six found significant reductions in systolic blood pressure and diastolic blood pressure when participants took nitrate supplements (22).
In addition, another review of 43 studies found that participants' systolic and diastolic blood pressure decreased by an average of 3.55 and 1.32 mm Hg, respectively, after they took nitrate supplements (23).
Like nitrates, flavonoid extracts have been shown to improve blood pressure (24, 25, 26).
Flavonoids have powerful antioxidant effects and are found in almost all fruits and vegetables (27).
Scientists believe that flavonoids not only increase the production of nitric oxide but also decrease its decomposition, promoting higher levels in general.
However, nitrates have more research that supports their blood pressure lowering effects than flavonoids.
Summary Vegetables and fruits contain several compounds, such as nitrate and flavonoids, that can help keep blood pressure under control by increasing nitric oxide levels.
4. Increase the performance of the exercise
Nitric oxide is involved in many cellular processes, including blood vessel widening or vasodilation. Wider blood vessels help increase the supply of nutrients and oxygen to the muscles that work during exercise, thus improving exercise performance.
This has made nitric oxide supplements popular among athletes and recreational gym aficionados.
These supplements often contain several ingredients that are said to increase nitric oxide, such as nitrate or the amino acids L-arginine and L-citrulline.
In many analyzes, nitrate has been shown to improve exercise performance in cyclists, runners, swimmers and even kayakers (28, 29, 30).
On the other hand, L-arginine has not been shown to be effective in improving exercise performance in many studies (31, 32, 33).
This is likely because most of the L-arginine that is ingested is metabolized or broken down before it reaches the bloodstream, whereas L-citrulline does not (34).
For this reason, L-citrulline is more effective than L-arginine in increasing nitric oxide and, therefore, exercise performance (35).
Summary Supplements intended to increase nitric oxide are commonly touted as performance enhancers. While the benefits that improve the performance of L-arginine are minimal, nitrate and L-citrulline may be worthwhile.
5. Can help control type 2 diabetes
Nitric oxide production is affected in people with type 2 diabetes (36).
This leads to poor health of the blood vessels, which can lead to conditions such as high blood pressure, kidney disease and heart disease over time.
Therefore, supplements that increase nitric oxide may have important implications for the treatment of diabetes and the prevention of diseases.
One study found that when people with type 2 diabetes took L-arginine, their nitric oxide production increased (37).
This increase in nitric oxide also led to increased sensitivity to insulin, allowing better control of blood sugar.
Another study in 144 people examined the effects of L-arginine in preventing or delaying the progression of type 2 diabetes (38).
Although L-arginine did not prevent people from developing diabetes, it did increase insulin sensitivity and improve blood sugar control.
But until more research is available, it is premature to recommend taking L-arginine supplements to treat diabetes.
Summary People with diabetes have a poor production of nitric oxide, which can cause harmful effects to health. It has been shown that L-arginine improves blood sugar control in people with diabetes, but more research is needed before it can be recommended.
Nitric oxide supplements are generally safe when taken in appropriate amounts (39, 40, 41).
However, there are some side effects to consider.
L-arginine taken in doses greater than 10 grams can cause upset stomach and diarrhea (42).
Beet juice supplements can also turn your urine and stool into a dark red color. This is a common but harmless side effect (43).
Before taking any supplement to increase nitric oxide, consult your doctor or dietitian.
Summary Nitric oxide supplements are generally considered safe. However, there are some side effects to consider, such as stomach upset and diarrhea, as well as dark red stool and urine.
The bottom line
Nitric oxide is a molecule that plays many important roles in human health.
It is claimed that many supplements increase nitric oxide in the body and provide impressive benefits for health and performance.
They usually contain ingredients such as nitrate or the amino acids L-citrulline and L-arginine.
However, other supplements, such as Pycnogenol, have also been shown to increase or maintain nitric oxide levels.
Reference: https: //www.healthline.com/nutrition/nitric-oxide-supplements