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Nitric oxide (NO) is among the most important molecules your body produces naturally. It serves as a vasodilator, meaning it signals the muscles inside your blood vessels to relax to increase blood flow.
But just because its function can be summed up so briefly doesn’t mean it’s just another molecule. This 1992 Molecule of the Year touted research that led to a 1998 Nobel Prize. (1)
Researchers have found several supplements which increase your body’s production of nitric oxide. There are some purported nitric oxide supplements, however, which end up being disappointments.
Below, you’ll find the benefits, suggested dosages, and side effects of the best nitric oxide supplements. Let’s maintain those healthy levels and get the most bang for your hard-earned buck!
What are the benefits of nitric oxide supplements?
Nitric oxide supplements, or nitric oxide boosters, are compounds used to increase nitric oxide production in the body. When you take one of these, you’re not ingesting actual nitric oxide, but rather a nitric oxide precursor that is thought to encourage more NO production in the body.
Why do people need nitric oxide supplements?
Nitric oxide levels decrease with an increase in age and stress and a decrease in exercise or nitrate-rich diet. One animal study even suggests that mouthwash decreases NO levels.
Even those who do not suffer from nitric oxide deficiency can reap the rewards of NO supplements. Here are the natural benefits of nitric oxide, as well as the added benefits of nitric oxide supplements. (2)
Increased Blood Flow
Nitric oxide’s primary function is as a vasodilator. This means NO loosens the inner wall of blood vessels. When blood circulates through the arteries more efficiently, several benefits follow. (3)
Better Nutrient Delivery
When the blood has an easier time flowing throughout the body, it also has an easier time delivering nutrients. The body needs vitamins and minerals, such as vitamin C, iron, zinc, and carbohydrates. Nitric oxide makes it easier for the body to transport those life-giving ingredients wherever they need to go.
In animal studies, nitric oxide supplements have been shown to increase the delivery of nutrients from the mother to a fetus. (4)
In general, this may help to improve the immune system.
Improved Exercise Performance
Not only do nutrients flow more freely, oxygen does as well. Of course, the body needs its O₂ —, especially during exercise.
When nitric oxide increases blood flow, performance during physical activity is improved. Energy is enhanced, and exhaustion is abated.
One study produced small, but consistent improvements in time to exhaustion trials. Though the findings were, technically speaking, statistically insignificant, the improvements may be more than meaningful in an elite sports context. (5)
Another study found that nitric oxide can be effective at improving endurance during exercise. (6)
Yet another bit of research concluded that those with less tolerance to exercise reacted more positively to nitric oxide supplements. Untrained exercisers improved their endurance, during both aerobic and anaerobic exercise. Aerobic means exercises which use up oxygen in the blood, whereas anaerobic refers to exercises which do not use any oxygen. (7)
Although this hasn’t been proven, there is a theoretical basis to believe nitric oxide supplements can lead to better muscle pump (the “swollen” feeling in muscles after a hard workout), which could help you with muscle building/muscle growth. This may happen because the muscle cells in the walls of these tissues have to reinforce themselves to withstand the extra pressure after extra nitric oxide has increased blood flow to muscle tissue.
Reduced Muscle Soreness & Faster Recovery Time
After an exercise regimen or an athletic performance, the muscles tend to grow sore. Scientists have shown that high-intensity workouts may benefit from nitric oxide supplements for increased performance but also decreased muscle soreness.
In a double-blind study, researchers observed a faster recovery in subjects who ingested citrulline malate (an organic compound from certain fruits). Muscle soreness dissipated at almost double the rate of the placebo group. (8)
Citrulline malate is thought to decrease muscle soreness because it helps to clear waste products related to soreness, like ammonia and lactate. (9)
Not only do these benefits make fitness easier, but they may also help you with fat loss, as you’ll be able to exercise harder and with less recovery time in between workouts.
Improved Symptoms of Erectile Dysfunction
Nitric oxide is closely connected to the little blue pill, Viagra. Increasing the production and flow of NO is actually the sole mechanism behind Viagra. When the blood vessels widen, the male reproductive system is allowed to function properly.
Low nitric oxide levels have been linked with erectile dysfunction. Patients with severe erectile dysfunction had low readings of L-citrulline and L-arginine (other NO enhancers). For men, a telltale sign of nitric oxide deficiency is erectile dysfunction. (10, 11)
Lower Blood Pressure
Pretty intuitively, relaxing the inner walls of blood vessels can immediately lower pressure. Blood pressure is the force of blood pushing against those inner walls. High blood pressure, also known as hypertension, is when that force is too high. High blood pressure affects millions of Americans every year. And unfortunately, high blood pressure can cause damage to your internal health rather silently.
Beetroot juice has been linked to lowering blood pressure. These findings were collated over six years of studies. (12)
Nitric oxide could eventually eliminate age as a risk factor in patients with high blood pressure. The research continues to fine-tune the best method for staving off age-related disease. (13)
Nitric oxide levels not only correlate with blood pressure but several other cardiovascular health issues. Our heart and blood vessels are lined with a layer of cells, a tissue called the endothelium. Endothelial dysfunction occurs when nitric oxide bioavailability is impaired, a major risk factor for hypertension and cardiovascular disease. (14)
Other Minor Health Benefits
- Increased growth hormone, during exercise (15)
- Increased insulin secretion (16)
- Decreased fatigue (17)
Top 9 Nitric Oxide Supplements for Health and Performance
Now that we know how NO affects the body, we can explore each of the primary nitric oxide supplements. Some naturally produced in the body and some taken supplementally.
Citrulline is a pure amino acid found in the body naturally. However, it was first discovered in watermelons. It is the most commonly used nitric oxide workout supplement and can increase the levels of three amino acids in the body.
The use of citrulline pre-workout results in decreased fatigue and increased endurance — for both aerobic and anaerobic exercises. Citrulline supplements relieve high blood pressure and can alleviate erectile dysfunction. And it lacks all the undesirable side effects of L-arginine, its metabolic successor.
Suggested dosage for L-citrulline:
Improved circulatory health and erectile dysfunction: 1,000 milligrams, three times a day (18)
2. Citrulline Malate
This metabolate of L-citrulline has the unique benefit of relieving muscle soreness. No other nitric oxide supplement has shown statistically significant recovery from the soreness of the muscles. (8)
Citrulline malate is an organic compound naturally found in many fruits. In high-intensity workout regimens, several grams of citrulline malate can reduce inflammation and pain while increasing endurance. (19)
Suggested dosage for citrulline malate:
Improved circulatory health: 1,760 milligrams, three times a day
Improved workout/athletic performance: 6,000 to 8,000 milligrams, one hour beforehand (18)
An essential amino acid found naturally in the body, L-arginine can also be taken as a supplement. Though improved athletic performance is commonly associated with L-arginine supplements, studies remain inconclusive. When taken along with BCAAs (branched chain amino acids), arginine may help to improve exercise performance. (20)
Some studies show a statistically significant effect, but others fail to show any. It seems L-arginine does not absorb well enough into the bloodstream before the intestines launch the arginine out the waste chute. (21)
Though a natural cog in the nitric oxide machine, arginine supplements have proven to be weak when it comes to enhancing NO production. Their main benefit over other supplements is in helping people with type 2 diabetes. But in every other way, its precursor L-citrulline reigns supreme.
Suggested dosage for L-arginine:
Pre-workout: 3 to 6 grams, up to three times a day
Dosage note: More than 10 grams of L-arginine at once can cause stomach pains and even diarrhea. (21)
Very interestingly, agmatine is a metabolite of L-arginine, and yet it seems to offer substantially stronger benefits. Human studies have shown potential to alleviate alcohol and drug withdrawal symptoms and may even possess antidepressant properties. (22)
Agmatine is also able to regulate nitric oxide levels. This affords it all the benefits of a standard nitric oxide supplement, on top of its unique properties.
Suggested dosage for agmatine:
For neuropathic pain: 1,300 to 2,670 milligrams daily (not to exceed 2,670 mg)
For improved cognition: 1.6 to 6.4 milligrams per kilogram of body weight daily, orally (not to exceed 6.4 mg/kg)
Dosage note: Agmatine should not be taken with dietary protein. This renders the potential benefits of agmatine ineffective because they use the same transporters. (23)
Besides chocolate, beets probably have more scientific studies proving their efficacy than any other nitric oxide supplement. Often consumed as beetroot juice or beetroot powder, this supplement has a high nitrate content. This is believed to enhance athletic performance and post-workout results. (24, 25)
Beetroot powder and juice have been found to lower blood pressure and increase plasma nitrate. Beetroot powder has also been shown to speed up recovery. The increased blood flow means nutrient delivery is streamlined, and muscle soreness is abated. (25, 26, 27, 28, 29)
A 2011 study even suggests that improved blood flow to the brain can help improve memory, focus, and emotions. (30)
Suggested dosage for beetroot:
6.4 to 12.8 milligrams of nitrate per kilogram of body weight. A teaspoon of some high-quality beetroot powder blends can contain the nitric oxide equivalent of three whole beets.
Dosage notes: Beetroot should be dosed on its nitrate content. Puree and smoothies are two excellent methods of consumption. The beets themselves can even be baked in an oven. These cooking techniques do not reduce the all-important nitrate content. (24)
Suggested dosage for curcumin:
500 milligrams curcumin with 20 milligrams piperine, three times a day, preferably with meals and a fat source (like olive oil or butter)
Dosage note: Curcumin is poorly absorbed by itself unless the intention is to improve digestion alone. Take curcumin with food. A common and successful pairing is piperine, a black pepper extract. Piperine helps the body to more readily absorb the curcumin and reap the myriad benefits. (37)
Though dozens of benefits have been studied in connection with cocoa and cocoa powder extract, no benefit is more agreed upon than increased blood flow. This is due to its influence on nitric oxide production. (38)
Common in dark chocolate, cocoa-related studies suggest other benefits include:
- Lowered cholesterol (39)
- Increased UV protection (40)
- Increased exercise performance (41)
- Decreased coronary heart disease (42)
Cocoa extract is a bioactive compound, which contains flavonols. Flavonols can act as antioxidants, anti-inflammatory agents, and anticarcinogens. Studies show that 5 to 26 grams of cocoa-rich dark chocolate contains 65 to 1,095 milligrams of flavanols. The standard dosage for flavanols found in cocoa is 500 to 1,000 milligrams per day, taken with meals.
Suggested dosage for cocoa:
25 to 40 grams of 85%-cocoa dark chocolate (about 200 calories)
Dosage notes: Milk chocolate and white chocolate contain little to no cocoa. (43)
Among the most common spices in the world, garlic has been shown to enhance nitric oxide production. Many studies are conducted using aged garlic extract. But fresh dietary garlic can also be consumed as a supplement. (44)
A well-known side effect is powerful, garlic-scented breath. Aged garlic is popular because it does not smell of fresh garlic, decreasing the undesirable halitosis.
Suggested Dosage for Garlic:
The minimum effective dosage of raw garlic is a single garlic clove, two or three times a day with meals. The maximum dosage for garlic supplements are as follows:
- 17.0 grams for a 150lb person
- 22.7 grams for a 200lb person
- 28.4 grams for a 250lb person
Microwaving garlic has been shown to somewhat damage the beneficial bioactive components. Grilling or roasting is acceptable as long as the garlic is sliced or crushed. Be careful though, raw garlic has been shown to be toxic in high dosages. (46)
Crataegus pinnatifida, otherwise known as thornapple or hawthorn, is a common plant found in Europe and many other regions of the world in jams and jellies, as well as wine. Its berries make up the hawthorn supplement.
Beyond increasing nitric oxide and fighting high blood pressure, hawthorn has been used to treat allergies, irregular heartbeat, and high cholesterol. Hawthorn can cause upset stomach, headache, and insomnia. (47)
Preliminary evidence shows hawthorn as a promising heart health supplement, but studies need to continue before conclusive evidence is presented. Not enough research has been performed to provide suggested dosages. (48, 49)
Side Effects of Nitric Oxide Supplements
With every supplement regimen, there can be side effects. Please consult your physician before adding any supplements to you diet, especially if you are on any medications.
Nitric oxide supplements have some individual side effects:
- High doses of L-arginine can cause stomach pains or even diarrhea.
- Citrulline malate has been known to occasionally cause stomach discomfort.
- Consuming beetroot or beetroot powder can turn the stool purple. This is often a purely superficial side effect and is more weird than harmful.
- Nitric oxide (NO) is among the molecules most critical to your body’s daily health.
- Nitric oxide supplements boost your body’s blood flow, leading to more efficient nutrient delivery, improved workout performance, reduced soreness of muscles, and lower blood pressure.
- The most effective nitric oxide supplements include beetroot, L-citrulline, citrulline malate, agmatine, curcumin, cocoa, garlic, and hawthorn.