Nitric oxide is produced by almost every cell type in the human body and is undoubtedly one of the most important molecules for maintaining blood vessels in good condition. Nitric oxide is a vasodilator, which means it relaxes the internal muscles of the blood vessels, causing them to widen. In this way, nitric oxide increases blood flow and lowers blood pressure.
Products that increase the level of nitric oxide in the body are today one of the most popular categories of sports supplements. These supplements do not contain nitric oxide alone. However, they contain compounds that your body can use to produce nitric oxide, and have been shown to provide many benefits to our health and performance.
There are several benefits to taking supplements, which are precursors of nitric oxide, below we present 5, in our opinion the most important!
1. They help in Erectile dysfunction
Erectile dysfunction (ED-Erectile Dysfunction) is the inability to achieve or maintain an erection that is strong enough to undergo sexual intercourse (1).
Nitric oxide is needed to relax the muscles of the penis. This relaxation allows the cells inside the penis to fill with blood to get a full erection (3).
One of the studies showed that L-citrulline improves the hardness of erection in 12 men with mild erectile dysfunction (4). The researchers concluded that L-citrulline is less effective than prescription drugs used to treat erectile dysfunction, such as Viagra. Nevertheless, L-citrulline was safe and well tolerated by the subjects. Two other nitrogen oxide enhancing supplements have been shown to treat erectile dysfunction - the amino acid L-arginine and Pycnogenol, a plant extract from pine. In several studies, the combination of L-arginine and Pycnogenol significantly improved sexual function in men with erectile dysfunction (5, 6, 7, 8).
In total, L-arginine and Pycnogenol also appear to be safe (9).
Nitric oxide plays an important role in maintaining the erection. It has been shown that several supplements, including L-citrulline, L-arginine and Pycnogenol, increase the level of nitric oxide in men with erectile dysfunction (ED).
2. It can reduce muscle soreness
The form of L-citrulline, called citrulline malate, may not only increase the production of nitric oxide, but also reduce muscle soreness.
Muscle pain is an uncomfortable experience that usually occurs after intense or unusual exercise (10).
This condition is defined as muscular pain with a delayed onset (colloquially, sour) and usually appears to be the strongest 24-72 hours after exercise. In one study, 41 people were randomly assigned to receive 8 grams of citrulline malate or placebo one hour before the highest number of repetitions of barbell bench press on a flat bench (11). People who received citrulline malate reported 40% less muscle pain after 24 and 48 hours after exercise, compared with those who took a placebo. Citrulline malate increases the production of nitric oxide, which increases blood flow to active muscles. Citrulic malate is believed to increase the supply of nutrients and help to remove waste products associated with muscle fatigue, such as lactate and ammonia (12). However, subsequent studies on the effect of citrulline after leg exercises have not shown that citrulline malate is helpful in treating muscle pain (13).
One explanation for this difference in results is that those taking part in the leg exercise study received 6 grams of citrulline malate, which is 2 grams less than in the previous study. Therefore, the ability of citrulline malate to reduce muscle pain may depend on the dose and physical activity. However, further research is needed to explicitly announce the verdict.
Citrulline malate is a form of L-citrulline which can help relieve muscle soreness by increasing the production of nitric oxide. The dose and type of exercise may affect the ability of citrulline malate to reduce muscle pain. It is believed that people with high blood pressure have an impaired ability to use nitric oxide in their bodies (14, 15).
3. It reduces blood pressure
High blood pressure occurs when the blood pressure of the pushing artery wall is consistently 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 rich in fruits and vegetables lowers blood pressure and therefore reduces the risk of disease (16). This led scientists 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 leafy vegetables like spinach and rocket. When you eat nitrates, your body transforms them into nitric oxide, which in turn causes relaxation and dilation of blood vessels, and hence - lowering blood pressure. Many studies have shown that nitrate can help lower blood pressure by increasing nitric oxide production (17, 18, 19, 20).
In one of the reviews, the effect of taking nitrogen supplements on blood pressure in adults (21) was analyzed. Of the 13 studies analyzed, six showed a significant reduction in systolic blood pressure and diastolic blood pressure when participants took supplements (22). What's more, in another review of 43 studies, it was found that systolic and diastolic blood pressure in participants decreased on average by 3.55 and 1.32 mmHg, respectively, after taking nitrogen supplements (23).
As with nitrates, flavonoid extracts improve blood pressure (24, 25, 26). Flavonoids have a strong antioxidant effect and occur in almost all fruits and vegetables (27). Scientists are convinced that flavonoids not only increase the production of nitric oxide, but also extend its lifespan in the body. Flavonoids, however, have not been tested for their ability to lower blood pressure as accurately as nitrates. We can therefore refer to a much smaller number of tests.
Vegetables and fruits contain several compounds, such as nitrates and flavonoids, which can help keep blood pressure under control by increasing levels of nitric oxide.
4. It increases training efficiency
Nitric oxide is involved in many cellular processes, including the widening of blood vessels or vasodilatation. The wider blood vessels help increase the supply of nutrients and oxygen to working muscles during exercise, thus increasing training performance.
Thanks to this, nitric oxide supplements have become popular among professional athletes and people practicing recreationally. These supplements often contain several ingredients that are supposed to increase the levels of nitric oxide, such as nitrates or the amino acids - L-arginine and L-citrulline.
In many analyzes, it has been shown that nitrate improves the results of physical exercise for cyclists, runners, swimmers, and even canoeists (28, 29, 30). On the other hand, L-arginine was not effective in improving exercise results in many studies (31, 32, 33).
This is probably due to the fact that most of the L-arginine consumed is metabolised or broken down before it gets a chance to enter the bloodstream, whereas L-citrulline is more resistant (34). For this reason, L-citrulline is more effective than L-arginine in increasing the level of nitric oxide, and consequently - exercise efficiency (35).
Supplements to increase nitric oxide levels are widely used as performance enhancers. While the benefits of L-arginine in terms of productivity increase are minimal, it is worth paying attention to nitrates and L-citruline. The production of nitric oxide in people with type 2 diabetes is impaired (36). This leads to poor blood vessel health, which can contribute to diseases such as hypertension, kidney disease and heart disease.
5. They can help in diabetic-related diseases
Therefore, supplements that increase nitric oxide may have important implications for the treatment of diabetes and disease prophylaxis. One study found that when people with type 2 diabetes were taking L-arginine, their production of nitric oxide increased (37). This increase in nitric oxide also led to an increase in insulin sensitivity, allowing better control of blood sugar levels.
In another study, 144 people evaluated the effect of L-arginine on preventing or delaying the progression of type 2 diabetes (38). Although L-arginine did not prevent the development of diabetes, increased insulin sensitivity and improved control of blood sugar levels. But until more research is available, it is premature to recommend taking L-arginine supplements to treat diabetes.
People with diabetes have an impaired production of nitric oxide, which can lead to very harmful health effects. L-arginine has been shown to improve control of blood sugar levels in people with diabetes, but more research is needed before it can be explicitly recommended.
Nitric oxide supplements are generally safe when taken in adequate amounts (39, 40, 41). However, there are some side effects to keep in mind. NL-arginine taken in doses above 10 grams may cause discomfort in the stomach and diarrhea (42).
Supplements from beetroot juice can also change the color of urine and stool to dark red. This is a common but harmless side effect (43).
Please consult your doctor or dietitian before accepting any supplements to increase nitric oxide levels.
Nitric oxide supplements are generally considered safe. However, there are some side effects to keep in mind, including potential discomfort in the stomach and diarrhea, as well as dark red stool and urine. Nitric oxide is a molecule that plays many important functions in maintaining the human body in good health and fitness. It is thought that many supplements increase the levels of nitric oxide in the body and provide impressive health benefits. They usually contain ingredients such as nitrates or L-citrulline and L-arginine amino acids - you can find them here!