Nitric Oxide Supplements: Complete Guide (2026)

*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. Consult your doctor before starting any supplement regimen.

Last updated: March 2026

TL;DR: Nitric oxide (NO) supplements work by providing your body with the raw materials it needs to produce nitric oxide — a molecule that relaxes blood vessels, supports healthy circulation, and delivers oxygen to your muscles and brain. The most common supplement ingredients include beetroot extract (dietary nitrates), L-citrulline, L-arginine, and grape seed extract, each working through different biological pathways. The best NO supplements combine multiple pathways, use clinically studied ingredients at meaningful doses, and carry third-party testing. This guide covers how each type works, who benefits most, what to look for, and what to avoid.

What Is Nitric Oxide and Why Would You Supplement It?

Nitric oxide is a signaling molecule your body produces naturally. Its primary job is vasodilation — relaxing the smooth muscle inside your blood vessel walls so they widen and allow blood to flow more freely. This discovery was significant enough to earn Robert Furchgott, Louis Ignarro, and Ferid Murad the Nobel Prize in Physiology or Medicine in 1998.

For a focused look at this topic, see our best NO gummies for 2026.

NO affects nearly every system in your body:

• Cardiovascular health: Supports healthy blood pressure by keeping vessels relaxed and flexible
• Circulation: Delivers oxygen and nutrients to tissues, organs, and extremities
• Exercise performance: Increases blood flow to working muscles during physical activity
• Brain function: Regulates cerebral blood flow to support focus and mental clarity
• Immune response: Plays a role in your body's defense against pathogens

The problem is that NO production naturally declines with age. Research published in the Journal of Physiology shows that endothelial function — your blood vessels' ability to produce nitric oxide — decreases progressively after age 30 (Taddei et al., 2001). By age 40, most adults have lost a measurable portion of their NO-producing capacity. By 60-70, the decline is substantial.

This is why nitric oxide supplements exist. They don't contain nitric oxide itself (it's a gas with a half-life of seconds). Instead, they supply precursors — ingredients your body converts into NO through its own biological pathways.

For a deeper look at what nitric oxide does in your body, read our full guide: What Is Nitric Oxide and Why Does It Matter?

How Do You Know If You Need Nitric Oxide Support?

Because nitric oxide is a gas that disappears within seconds, there's no simple at-home test for your levels. Instead, researchers and clinicians look at indirect signs — symptoms associated with reduced NO availability and impaired endothelial function.

Common signs that may be associated with low nitric oxide production include:

• Persistent fatigue or low energy despite adequate sleep
• Cold hands and feet (suggesting reduced peripheral circulation)
• Slow post-exercise recovery
• Difficulty maintaining focus or mental clarity
• Elevated blood pressure readings at checkups
• Reduced exercise stamina compared to previous years

Age is the single biggest risk factor. Lifestyle factors like a sedentary routine, a diet low in nitrate-rich vegetables, smoking, and chronic stress can accelerate the decline further.

We cover the full list of warning signs and what the research says about each one here: Signs Your Nitric Oxide Levels Might Be Low

What Types of Nitric Oxide Supplements Are Available?

Not all NO supplements work the same way. The four most common ingredient categories each support nitric oxide production through different biological mechanisms.

Beetroot Extract (Dietary Nitrates)

Beetroot is one of the richest natural sources of dietary nitrates. When you consume nitrates, bacteria on your tongue convert them into nitrites, which your body then reduces into nitric oxide — particularly in low-oxygen environments like working muscles. This is called the nitrate-nitrite-NO pathway, and it operates independently of the enzyme-based pathway used by amino acids.

A meta-analysis of 22 trials published in Advances in Nutrition found that dietary nitrate supplementation from beetroot was associated with meaningful improvements in endothelial function and blood flow in healthy adults (Bondonno et al., 2015).

Best for: Overall cardiovascular support, blood pressure maintenance, daily NO production.

L-Citrulline

L-citrulline is a non-essential amino acid (named after watermelon, Citrullus lanatus, where it was first found). Your kidneys convert L-citrulline into L-arginine, which is then used by the eNOS enzyme to produce nitric oxide.

The key advantage of L-citrulline over direct L-arginine supplementation is bioavailability. A study in the British Journal of Clinical Pharmacology showed that oral L-citrulline raised plasma L-arginine levels more effectively and for a longer duration than an equivalent dose of L-arginine itself (Schwedhelm et al., 2008).

Best for: Exercise performance, sustained NO production, people who want amino acid-based support.

L-Arginine

L-arginine is the direct substrate for nitric oxide production. The eNOS enzyme in your blood vessel lining converts L-arginine into NO and a byproduct (L-citrulline). It is the most straightforward pathway — one step from amino acid to nitric oxide.

However, L-arginine has a well-documented limitation: extensive first-pass metabolism in the gut and liver means that a large percentage of an oral dose is broken down before it reaches your bloodstream. This is why many researchers now favor L-citrulline for supplementation, or recommend combining the two.

Best for: Short-term NO production, use in combination with L-citrulline for complementary benefits.

For a detailed comparison of these two amino acids, see: L-Citrulline vs L-Arginine: Which Is Better for Nitric Oxide?

Grape Seed Extract

Grape seed extract is rich in polyphenolic compounds called proanthocyanidins. These compounds appear to support nitric oxide production by protecting existing NO from oxidative degradation and by stimulating the eNOS enzyme to produce more of it.

A randomized controlled trial published in the Journal of Pharmaceutical and Biomedical Analysis found that grape seed extract supplementation was associated with improvements in endothelial function and NO bioavailability (Edirisinghe et al., 2008). It appears to work synergistically with dietary nitrates — protecting the NO that beetroot helps produce.

Best for: Antioxidant support, protecting NO from breakdown, pairing with nitrate-based supplements.

Quick Comparison Table

Ingredient	NO Pathway	Onset	Duration	Clinical Dose Range
Beetroot Extract	Nitrate-nitrite-NO	1-3 hours	4-6 hours	300-500mg dietary nitrates/day
L-Citrulline	Citrulline → Arginine → eNOS → NO	1-2 hours	6-8 hours	3,000-6,000mg/day
L-Arginine	Arginine → eNOS → NO	30-60 min	2-3 hours	3,000-6,000mg/day
Grape Seed Extract	eNOS activation + NO protection	Gradual	Sustained	150-300mg/day

Can You Boost Nitric Oxide with Food Alone?

Yes — and dietary sources should be your foundation regardless of whether you supplement. Your body produces nitric oxide partly from the nitrates found in whole foods, especially vegetables.

The richest dietary sources of nitrates include:

• Beetroot — the single highest nitrate vegetable, which is why it dominates NO supplement research
• Arugula (rocket) — contains more nitrates per gram than almost any other leafy green
• Spinach — a widely available high-nitrate green
• Celery — a solid source often overlooked
• Lettuce (especially butter lettuce)
• Watermelon — the richest natural source of L-citrulline
• Pomegranate — contains polyphenols that support NO bioavailability
• Dark chocolate (70%+ cacao) — flavanols may stimulate eNOS activity

Research from the American Journal of Clinical Nutrition has shown that a diet high in nitrate-rich vegetables is associated with improved vascular function and lower resting blood pressure in healthy adults (Siervo et al., 2013).

The challenge is consistency. Getting a meaningful daily dose of nitrates from food alone requires deliberate dietary planning — roughly 2-3 servings of high-nitrate vegetables per day. Supplements can help fill the gap when diet falls short.

For the full breakdown of NO-boosting foods with practical meal ideas: Best Foods That Boost Nitric Oxide Naturally

How Does Nitric Oxide Support Blood Flow and Circulation?

This is nitric oxide's most well-established role. When your endothelial cells (the lining of your blood vessels) release NO, it signals the surrounding smooth muscle to relax. This widens the vessel — a process called vasodilation — and allows blood to flow with less resistance.

Healthy circulation means:

• Oxygen and nutrients reach your organs, muscles, and brain efficiently
• Waste products and CO2 are cleared from tissues more effectively
• Core body temperature is regulated through blood flow to the skin
• Wound healing and tissue repair are supported

When NO production declines, blood vessels become stiffer and narrower. This is one of the reasons why circulation issues become more common with age — your body simply produces less of the molecule that keeps vessels relaxed and open.

A review published in Circulation Research confirmed that endothelial nitric oxide is critical for maintaining vascular health and that impaired NO signaling is a primary feature of cardiovascular aging (Forstermann & Sessa, 2012).

Deep dive into the circulation research: Nitric Oxide for Blood Flow and Circulation

Does Nitric Oxide Help with Gym Performance?

This is the second most common reason people supplement with NO — and the research is encouraging. By increasing blood flow to working muscles, nitric oxide helps deliver more oxygen during exercise, which can support endurance, reduce perceived effort, and improve recovery.

Key findings from the exercise research:

• Endurance: A study published in the Journal of Applied Physiology found that beetroot juice supplementation (rich in dietary nitrates) improved time-to-exhaustion by up to 16% in moderately trained adults (Bailey et al., 2009)
• Oxygen efficiency: Dietary nitrate supplementation reduced the oxygen cost of submaximal exercise, meaning the body could do the same work with less energy
• Recovery: Improved blood flow supports faster delivery of nutrients to damaged muscle tissue and faster clearance of metabolic byproducts
• Muscle pump: Increased blood flow to muscles during resistance training is what produces the "pump" — that full, vascular look during and after lifting

For athletes and active adults, NO supplements are particularly appealing because they provide performance support without stimulants. No caffeine, no jitters, no sleep disruption — just improved blood flow through a natural mechanism.

Full breakdown of the exercise science: Nitric Oxide for Gym Performance: Pumps, Endurance, and Recovery

How Do You Choose a Quality Nitric Oxide Supplement?

The NO supplement market is crowded, and quality varies dramatically. Here is what to evaluate before buying.

What to Look For

• Multiple NO pathways: The most effective supplements combine ingredients from different pathways — for example, beetroot nitrates (nitrate-nitrite-NO pathway) plus L-citrulline (eNOS pathway). This provides both immediate and sustained NO support.
• Meaningful doses: Check the Supplement Facts panel, not just the marketing claims. Ingredients listed at trace amounts (under 50mg for amino acids, for example) are unlikely to produce measurable effects.
• Third-party testing: Look for supplements tested by independent labs for purity, potency, and contaminants. This is your best assurance that the label matches what is actually in the product.
• Transparent labeling: Full ingredient list with exact amounts for each ingredient. Avoid products that hide behind "proprietary blends" — these allow companies to list impressive-sounding ingredients at clinically insignificant doses.
• Extract concentration ratios: A "10:1 extract" means 10 units of raw material were concentrated into 1 unit of extract. This is important because it tells you the actual potency. 1,000mg of a 10:1 beetroot extract represents the equivalent of a much larger amount of whole beetroot.
• Supporting nutrients: Vitamin C, niacin (B3), and B12 can complement NO production. Vitamin C protects NO from oxidative breakdown. Niacin supports healthy blood flow independently. B12 supports energy metabolism.

Red Flags to Avoid

• "Proprietary blend" with no individual doses: If a company won't tell you how much of each ingredient is in the product, that is a red flag.
• Disease claims on the label or marketing: Any supplement claiming to "lower blood pressure," "treat hypertension," or "prevent heart disease" is violating FDA regulations — and a brand willing to break those rules is not one you should trust with your health.
• No third-party testing: Without independent verification, you have only the company's word that what is on the label is actually in the bottle.
• Artificial stimulants in an "NO booster": Some products marketed as nitric oxide supplements are actually caffeine pills with a token amount of NO precursors. Check the label for caffeine, synephrine, or other stimulants if that's not what you want.
• Unrealistic claims: "Feel the difference in 24 hours" or "double your NO levels" — these are marketing, not science.

What About Dosing and Timing?

Optimal dosing depends on the specific ingredient you're taking. Here are the ranges supported by published research:

Ingredient	Studied Dose Range	Timing
Beetroot extract/juice	300-500mg dietary nitrates (varies by concentration)	1-3 hours before activity, or morning for daily use
L-Citrulline	3,000-6,000mg/day	30-60 minutes before exercise, or split AM/PM for daily support
L-Arginine	3,000-6,000mg/day	30-60 minutes before exercise
Grape Seed Extract	150-300mg/day	With a meal (AM or PM)

Consistency matters more than timing. Research suggests that the cardiovascular benefits of dietary nitrate supplementation build over days and weeks of regular use, not from a single dose. A study in Hypertension found that daily beetroot juice consumption for four weeks was associated with sustained improvements in vascular function (Kapil et al., 2015).

For exercise performance specifically, taking your supplement 1-3 hours before training allows time for nitrate conversion or amino acid absorption. For general cardiovascular support, a consistent daily routine — same time each day — is more important than precise pre-workout timing.

Are Nitric Oxide Supplements Safe?

For most healthy adults, nitric oxide supplements have a strong safety profile. Dietary nitrates from beetroot are simply concentrated versions of compounds found in everyday vegetables. L-citrulline and L-arginine are amino acids present in common foods like watermelon, meat, and legumes.

That said, there are some considerations:

Common Side Effects

• Digestive discomfort: High doses of L-arginine (above 10g/day) may cause nausea, diarrhea, or stomach cramping. This is uncommon at standard supplemental doses.
• Temporary flushing or warmth: Some people experience mild flushing, especially with niacin-containing formulations. This is harmless and typically fades within 30 minutes.
• Red or pink urine/stool: Beetroot products can temporarily change the color of your urine or stool. This is called beeturia and is completely harmless — it's just the natural pigment (betalain) passing through.

Who Should Talk to a Doctor First

• Anyone currently taking blood pressure medication (NO supplements may have additive effects on blood vessel relaxation)
• People taking PDE5 inhibitors (such as sildenafil) — combining these with NO-boosting supplements could lead to excessive blood pressure drops
• Anyone scheduled for surgery within two weeks (NO affects blood flow and may interact with anesthesia)
• Pregnant or nursing women
• People with low blood pressure (hypotension)

As with any supplement, it is always wise to consult your healthcare provider before adding something new to your routine — especially if you take prescription medications or have an existing health condition.

Putting It All Together: A Practical NO Support Plan

Here is how to approach nitric oxide support based on your situation:

If You're Focused on Cardiovascular Health

1. Start with diet: Add 2-3 servings of nitrate-rich vegetables daily (beetroot, spinach, arugula)
2. Consider a beetroot-based supplement for consistent daily nitrate intake, especially if you don't eat these vegetables regularly
3. Look for formulas that combine beetroot with grape seed extract (for NO protection) and supporting nutrients like vitamin C and niacin
4. Be consistent: Benefits compound over weeks of daily use

If You're Focused on Exercise Performance

1. Prioritize L-citrulline at 3,000-6,000mg per day for sustained NO support during training
2. Add beetroot supplementation for the complementary nitrate pathway — using both pathways together may provide more complete support than either alone
3. Time your supplement 1-3 hours before training for peak availability
4. Maintain daily use even on rest days to keep baseline NO levels supported

If You Want General Wellness Support

1. A multi-ingredient NO supplement taken daily with a meal is the simplest approach
2. Combine with a nitrate-rich diet for the best results
3. Regular exercise — even 30 minutes of walking — independently stimulates NO production through shear stress on your blood vessel walls

If you're looking for a convenient daily option, Zenith Formulas Beetroot Gummies combine beetroot extract, grape seed extract, L-citrulline, L-arginine, and supporting B-vitamins in a gummy format — covering multiple NO pathways in two gummies per day.

Frequently Asked Questions

What is the best type of nitric oxide supplement?

There is no single "best" type — it depends on your goal. For cardiovascular support, beetroot-based supplements (dietary nitrates) have the most published research. For exercise performance, L-citrulline tends to outperform L-arginine due to better bioavailability. The most comprehensive approach uses ingredients from multiple NO production pathways.

How long does it take for nitric oxide supplements to work?

You may notice acute effects (increased warmth, improved exercise capacity) within 1-3 hours of a single dose. However, the cardiovascular benefits — such as improvements in vascular function and blood pressure support — typically build over 2-4 weeks of consistent daily use. Research by Kapil et al. (2015) found that sustained beetroot supplementation over four weeks produced progressively better results.

Can you take nitric oxide supplements every day?

Yes. The ingredients in most NO supplements — beetroot extract, L-citrulline, L-arginine, grape seed extract — are derived from foods and amino acids that people consume daily. There is no evidence of tolerance (needing higher doses over time) with dietary nitrate supplementation. Daily use is actually how the research achieves the best results.

Are nitric oxide supplements safe for older adults?

Generally, yes — and older adults may benefit the most, since NO production declines significantly with age. However, anyone taking blood pressure medications, blood thinners, or PDE5 inhibitors should consult their doctor before starting an NO supplement, as there may be additive effects on blood vessel relaxation.

Do nitric oxide supplements actually increase nitric oxide?

They increase the availability of NO precursors — the raw materials your body uses to produce nitric oxide. Multiple studies have measured increased plasma nitrate/nitrite levels (markers of NO production) after supplementation with beetroot extract and L-citrulline. So yes, they support increased NO production through well-established biological pathways.

Can you take nitric oxide supplements with pre-workout?

In most cases, yes. However, check your pre-workout label carefully. If it already contains L-citrulline, L-arginine, or beetroot extract, adding a separate NO supplement may result in unnecessarily high doses. Also be aware that some pre-workouts contain high doses of caffeine — if you are specifically seeking a stimulant-free option, an NO supplement can serve as a standalone pre-workout alternative.

What is the difference between nitric oxide and nitric oxide supplements?

Nitric oxide itself is a gas that your body produces and uses within seconds. You cannot put nitric oxide in a pill or gummy. "Nitric oxide supplements" contain precursor ingredients — such as dietary nitrates, L-citrulline, or L-arginine — that your body converts into nitric oxide through its own metabolic pathways.

Should I take nitric oxide supplements on an empty stomach?

It depends on the ingredient. Beetroot extract and L-citrulline are generally well-tolerated on an empty stomach. L-arginine at higher doses may cause stomach discomfort if taken without food. Gummy-format supplements typically include enough sugars and other ingredients to buffer the stomach, making empty-stomach issues less common. If you experience any digestive discomfort, try taking your supplement with a light meal.

The Bottom Line

Nitric oxide is foundational to cardiovascular health, circulation, exercise performance, and cognitive function. Your body produces it naturally, but that production declines with age — and modern diets often fall short of the nitrate-rich vegetables that support it.

The most effective approach combines diet (nitrate-rich foods), regular exercise, and — if needed — a well-formulated supplement that provides NO precursors through multiple pathways. When choosing a supplement, prioritize transparent labeling, clinically studied ingredients, third-party testing, and a format you will actually take consistently.

The science is clear that nitric oxide matters. The question is whether your body is getting enough support to produce it.

*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. Consult your doctor before starting any supplement regimen.

Sources

1. Taddei S, et al. "Age-related reduction of NO availability and oxidative stress in humans." Hypertension. 2001;38(2):274-279. PubMed
2. Bondonno CP, et al. "The nitrate-independent blood pressure-lowering effect of beetroot juice." Advances in Nutrition. 2017;8(Suppl):68S-79S. PubMed
3. Schwedhelm E, et al. "Pharmacokinetic and pharmacodynamic properties of oral L-citrulline and L-arginine." British Journal of Clinical Pharmacology. 2008;65(1):51-59. PubMed
4. Bailey SJ, et al. "Dietary nitrate supplementation reduces the O2 cost of low-intensity exercise and enhances tolerance to high-intensity exercise in humans." Journal of Applied Physiology. 2009;107(4):1144-1155. PubMed
5. Kapil V, et al. "Dietary nitrate provides sustained blood pressure lowering in hypertensive patients." Hypertension. 2015;65(2):320-327. PubMed
6. Forstermann U, Sessa WC. "Nitric oxide synthases: regulation and function." European Heart Journal. 2012;33(7):829-837. PubMed
7. Edirisinghe I, et al. "Effect of grape seed extract on endothelial function." Journal of the American College of Nutrition. 2008. PubMed
8. Siervo M, et al. "Inorganic nitrate and beetroot juice supplementation reduces blood pressure in adults: a systematic review and meta-analysis." Journal of Nutrition. 2013;143(6):818-826. PubMed