Nitric oxide boosters are supplements that increase your body’s synthesis of nitric oxide, or NO. Since pure NO is a gas, you can’t take it in supplement form, but you can take precursors that increase your body’s endogenous synthesis.
Nitric oxide increases blood flow throughout your body, so nitric oxide boosters are popular for applications that take advantage of better blood supply: improving athletic performance, enhancing sexual performance and erectile function, and reducing heart disease risk by lowering blood pressure.
Want to make the most of nitric oxide? Here are the key benefits, plus info on the best way to incorporate NO into your supplement stack.
Research
Benefits
1. Nitric oxide can boost endurance performance
Nitric oxide first rocketed to popularity in the sports nutrition world because of its effects on cycling, running, and other endurance exercise.
Studies using beet root powder, a very good source of nitric oxide, found substantial increases in endurance thanks to increased levels of nitric oxide. One study found a 5% improvement in 5k performance after taking a beetroot supplement (1).
The difference seemed to be in the second half of the 5k trial, indicating that improved endurance was likely responsible for the improved times.
2. L-arginine and beetroot boost NO through different pathways
According to a review article on nitric oxide in sports performance by Raul Bescos and other researchers at the University of Barcelona in Spain, the body produces nitric oxide through two primary pathways: the NOS dependent and NOS independent pathways (2).
The first pathway is modulated by the presence of the amino acid L-arginine, which can be used by the body to generate nitric oxide.
Another amino acid that is useful in this pathway is L-citrulline, because the body can convert it into L-arginine, and then use that to generate nitric oxide.
The second pathway is dependent on nitrates, which are what are found in beetroot powder.
So, it follows, to maximize your nitric oxide levels, you’d want a supplement that provides both a source of nitrates, like beetroot powder, and a source of L-arginine and perhaps L-citrulline as well.
3. Nitric oxide may also help with strength performance
When it comes to resistance training, evidence is more circumstantial, but there does seem to be a relationship between nitric oxide levels and the improvement in strength that occurs with training.
One study published in the Sport Science & Medicine in 2007 followed a group of sedentary people who started a strength training program for the first time (3).
As their strength improved, the researchers found that levels of nitric oxide in the blood increased as well. Further, high intensity weight training led to a greater increase than low intensity weight training.
This has led some people to hypothesize that the relationship works in reverse, too–i.e. that increases in nitric oxide levels will lead to an increase in strength. While this has yet to be tested in a large and robust study, it’s an intriguing prospect.
4. Nitric oxide can help with diabetes and erectile dysfunction
Emerging evidence suggest that low levels of nitric oxide play a role in erectile dysfunction too. Doctors first noticed this in patients with type 2 diabetes.
In 2004, researchers from several different medical institutions published a paper that showed a specific mechanism by which diabetes interferes with erectile function (4). They identified a cellular pathway mediated by nitric oxide that was inhibited in diabetes.
Other research indicated that supplementing with L-arginine (which boosts nitric oxide production) could potentially help with erectile dysfunction:
One study found that 31% of men with erectile dysfunction who were given an L-arginine supplement reported improvements, compared to only 11% of men in the control group (5).
While there are plenty of other causes of erectile dysfunction, like low testosterone, this evidence indicates that a nitric oxide supplement could be worth a try.
5. Nitric oxide supplements could decrease blood pressure
The vasodilating effects of nitric oxide have long been known in the field of cardiology, and several pharmaceutical drugs target nitric oxide related cellular pathways to treat heart disease.
Researchers have wondered whether a supplement that boosts nitric oxide could be beneficial for heart health; one recent study found that three grams per day of citrulline reduced blood pressure and improved the oxygenation of peripheral tissue in the body (6).
Other research in animals also supports a relationship between nitric oxide supplements and lowered blood pressure. A study in mice showed that NO supplementation increased nitric oxide in the kidneys, which in turn was able to lower blood pressure (7).
Nitric oxide side effects
Supplements that boost nitric oxide seem to be pretty safe. They are relatively new, so long-term data isn’t available, but since the best nitric oxide boosters are natural compounds (powder from beets and the ubiquitous amino acid L-arginine), it’s hard to envision how adding these to your diet would have negative effects.
Watch out for nitrates that do not come from beets. Nitrates are also added to processed meats as a preservative, and some scientists suspect this is the reason why these processed meats like bacon, sausage, and salami are associated with an increased risk of colorectal cancer, though this is controversial (8).
Because consuming root vegetables like beets is not known to be associated with disease, other researchers suggest that beets are a safe way to consume nitrates for performance (9).
Nitric oxide dosage
Dosage standards are vague when it comes to how to properly boost your nitric oxide levels, but research gives some guidance.
Aim for at least 500 mg of nitrates from beets for boosting NO. If you are getting nitrates from beetroot powder, research suggests that you want at least 500 mg of nitrates per serving to get the optimal effect.
L-arginine research uses three to six grams per day. When it comes to nitrate generated from L-arginine, studies have tested anywhere from three to eight grams of L-arginine per day, but this is mostly from medical research that’s attempting to generate nitric oxide to help, for example, heart disease patients with circulatory issues.
1:1 citrulline to L-arginine ratio is a good place to start. There’s less guidance on exactly how to combine L-arginine with citrulline, but most studies and supplements use a 1:1 ratio, which is a good place to start given the biochemistry of how both of these compounds contribute to nitric oxide synthesis.
Nitric oxide benefits FAQ
Q: Are nitric oxide supplements dangerous?
A: Most evidence suggests that the traditional supplements for increasing nitric oxide levels, like citrulline and L-arginine, are very safe.
Chronic, high consumption of processed meats that are high in nitrate levels, like bacon, sausage, and ham, is associated with an increased risk for colorectal cancer, but whether nitrate is the causal agent in this relationship is not clear.
Other epidemiological research has found that increased consumption of root vegetables like beets, which are a natural source of dietary nitrates, do not increase the risk of colorectal cancer, so any evidence linking nitrates to health risks is tenuous at best.
Moreover, most nitric oxide supplements don’t rely directly on nitrates as their primary nitric oxide boosters, so for our top ranked supplements, this is a moot point anyways.
Q: Can you get nitric oxide from food?
A: Compounds that boost nitric oxide aren’t very common in foods, but a few foods do have significant levels of nitric oxide boosters.
Chief among these are beets, which contain high concentrations of nitrates. Beets themselves are used as a source for beetroot juice or beet root powder, which have a substantial body of scientific research supporting their use as a way to boost nitric oxide.
Most other dietary sources of nitric oxide boosters are pretty far back, but some emerging research suggests that garlic may be able to increase your body’s nitric oxide production as well, so keep an eye out for more research on that topic in the near future.
Q: What does nitric oxide do?
A: Nitric oxide plays a key role in several biological functions in your body, but chief among these is the relaxation of the smooth muscles that control the constriction of your blood vessels.
When these muscles relax, your blood vessels dilate, your blood pressure drops, and oxygen supply to your muscles increases.
These effects explain why nitric oxide is such a powerful pre-workout performance enhancer: with more blood flow and better tissue oxygenation, generating aerobic energy is much easier for your muscles.
Q: How do you increase nitric oxide levels in your body?
A: Nitric oxide levels can be increased in your body in a variety of ways, but one of the easiest ways it by exercise. A study published in the Journal of Clinical Biochemistry and Nutrition in 2017 was able to demonstrate that increased amounts of exercise are associated with higher levels of nitric oxide, which helps reduce blood pressure and even increases levels of antioxidant enzymes in the blood (10).
Beyond basic lifestyle changes, supplementation can be another very effective way to increase nitric oxide levels in the body.
Supplements like citrulline, L-arginine, and beet root powder or beet juice are all effective ways to increase levels of nitric oxide in your body, and our top-ranked nitric oxide supplements use combinations of these and other supplemental sources of nitric oxide precursors to boost nitric oxide inside your body.
Q: Do nitric oxide supplements work?
A: Yes, nitric oxide supplement ingredients like citrulline, arginine, and beet root powder have all been demonstrated in clinical research as effective ways to improve athletic performance, increase sexual function, and perhaps even decrease risk factors for heart disease.
It’s important to note, though, that nitric oxide is far from the only factor that plays into any of these outcomes.
Caffeine pills, for example, can increase endurance performance as well, through separate pathways that have nothing to do with nitric oxide, and while one in three men with erectile dysfunction can benefit from supplements to increase nitric oxide levels, two in three don’t, suggesting that other factors are at play as well.
Related: Our best nitric oxide supplement picks
Summary
Nitric oxide boosters are a powerful category of supplement that modulates blood flow, potentially aiding everything from exercise performance to sexual function and blood pressure.
The key ingredients to look for are beetroot extract, L-arginine, and citrulline, as these help stimulate different NO synthesis pathways in the body.
