Best Nitric Oxide Supplements for Men (2026): L-Citrulline vs Beetroot vs L-Arginine

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Last updated: October 2026. We checked every product label and dose in this guide.

Quick answer: the best nitric oxide supplements for most men are plain L-citrulline powders, taken at 3 to 6 grams a day. L-citrulline raises blood arginine more reliably than L-arginine itself and has the most direct research in men with mild erection problems. Beetroot works through a different pathway and is a good second choice. L-arginine is the weakest of the three for most men.

Shopping for the best nitric oxide supplements is confusing because no product actually contains nitric oxide. It is a gas your body makes to relax blood vessels. What you buy is a raw material: L-citrulline, L-arginine or the nitrate found in beetroot.

This guide compares the three, picks a product for each and explains doses and safety. Nitric oxide boosters support circulation. They do not treat the cause of erectile dysfunction, so also read can you reverse ED naturally?

Which are the best nitric oxide supplements to buy?

Choose by ingredient first, then by brand. Here is our pick for each type of buyer:

• Best overall: Nutricost Pure L-Citrulline powder, 3 g per scoop.
• Best beetroot option: Micro Ingredients Organic Beet Root Powder.
• Best for the gym: Nutricost L-Citrulline Malate 2:1 powder.
• Best L-arginine: NOW Arginine 1,000 mg tablets.
• Best capsule blend: Nutricost Nitric Oxide Booster.

L-citrulline vs beetroot vs L-arginine: quick comparison

Ingredient	How it raises nitric oxide	Typical daily dose	Best for
L-citrulline	Converted to arginine in the kidneys	3–6 g	Daily blood-flow support
Beetroot (nitrate)	Nitrate becomes nitrite, then nitric oxide	About 300–500 mg nitrate	Blood pressure, endurance
L-arginine	Direct raw material, much is lost in the gut and liver	3–6 g	Men who already tolerate it
Citrulline malate	Citrulline bound to malic acid	6–8 g before training	Gym performance

The 5 best nitric oxide supplements reviewed

1. Nutricost Pure L-Citrulline powder: best overall

This is pure L-citrulline with no malate and no flavoring. One scoop gives 3 g, and the 600 g tub holds 200 servings. One or two scoops a day covers the 3 to 6 g range used in blood-flow studies.

Best for: the lowest cost per effective dose. Skip if: you dislike a slightly sour powder in water.

2. Micro Ingredients Organic Beet Root Powder: best beetroot option

This is a plain organic beetroot powder with about 3.5 g per scoop. It mixes into water or a smoothie and has an earthy beet taste.

One caution applies to every beet powder: the label does not state a nitrate amount, and nitrate levels vary between crops. Treat it as a food-based option, not a measured dose.

Best for: men who want the nitrate pathway from a whole food. Skip if: you have had kidney stones, because beets are high in oxalate.

3. Nutricost L-Citrulline Malate 2:1: best for the gym

Citrulline malate is the form used in most exercise studies. Each scoop gives 3 g, and training research usually uses 6 to 8 g about an hour before exercise.

Remember that a 2:1 product is only about two-thirds citrulline by weight, so you need more powder to match pure L-citrulline.

Best for: pre-workout use. Skip if: your only goal is everyday circulation.

4. NOW Arginine 1,000 mg: best L-arginine

NOW sells L-arginine in 1,000 mg tablets, 120 per bottle. The listing below is a pack of three bottles. A daily dose of 3 to 6 g means three to six tablets.

Arginine is the direct raw material for nitric oxide, but much of an oral dose is broken down before it reaches the blood. Higher doses often cause stomach upset.

Best for: men who prefer tablets and already do well on arginine. Skip if: you have had a heart attack or get cold sores often.

5. Nutricost Nitric Oxide Booster: best capsule blend

This is a capsule blend that supplies 2,250 mg per serving, with 180 capsules and 60 servings per bottle. The listing states third-party testing.

The trade-off is dose. A 2,250 mg blend is well below the 3 to 6 g of citrulline used in studies, so it suits convenience more than maximum effect. Check the label for the amount of each ingredient.

Best for: men who will not use a powder. Skip if: you want a full research dose.

Is L-citrulline better than L-arginine for nitric oxide?

Yes, for most men. In a pharmacokinetic study, oral L-citrulline raised blood arginine levels more than the same dose of L-arginine. Citrulline passes through the gut and liver intact, then the kidneys turn it into arginine.

It is also the only one of the three tested directly for erections. In a small trial of 24 men with mild ED, 1.5 g a day for a month improved erection hardness in half of them, compared with 2 men on placebo. The trial was small and short, so treat it as early evidence. Our best L-citrulline supplement guide covers the options.

Does beetroot really boost nitric oxide?

Yes, through a separate route. Bacteria in your mouth turn the nitrate in beets into nitrite, which the body converts to nitric oxide. A meta-analysis of 16 trials found that nitrate and beetroot juice lowered systolic blood pressure by about 4 mmHg.

Two practical points matter. Antibacterial mouthwash can block the conversion, so avoid it around your dose. And most studies used beetroot juice with a measured nitrate content, which powders rarely state.

How much should you take, and when?

• L-citrulline: 3 to 6 g a day, in one or two doses, with or without food.
• Citrulline malate: 6 to 8 g about an hour before training.
• Beetroot: a dose providing roughly 300 to 500 mg of nitrate, two to three hours before exercise.
• L-arginine: 3 to 6 g a day in divided doses.

Give any of them at least four weeks of daily use before judging the result. See L-citrulline for blood flow for timing details.

Do nitric oxide supplements help with erectile dysfunction?

They may help mild cases a little. They are far weaker than prescription drugs. An erection depends on nitric oxide relaxing the vessels of the penis, so the logic is sound, but the trials are small.

ED can also be an early sign of heart disease. If it is new or persistent, see a doctor first. Read erectile dysfunction and heart disease and our comparison of ED medications.

Who should not take nitric oxide boosters?

Talk to your doctor before using any of them if you:

• take nitrate heart medication such as nitroglycerin;
• take Viagra, Cialis or another ED drug, because the blood-pressure effects can add up;
• take blood-pressure medication or have low blood pressure;
• have had a heart attack. A trial of L-arginine after heart attack was stopped early over safety concerns;
• have kidney disease or a history of kidney stones.

How we chose the best nitric oxide supplements

We compared products on four points: a single, clearly labeled main ingredient, an effective dose per serving, cost per day and a manufacturer that follows GMP standards. We read the labels and Amazon listings for every pick. We did not run our own lab tests.

Nitric oxide supplements FAQ

Bottom line

The best nitric oxide supplements for most men are simple ones. Start with pure L-citrulline at 3 to 6 g a day. Add or switch to beetroot if blood pressure or endurance is your main goal, and choose citrulline malate for the gym. L-arginine is the weakest choice for most men. None of these replace medical care for erection or heart problems.

References

• Schwedhelm E, et al. Pharmacokinetic and pharmacodynamic properties of oral L-citrulline and L-arginine. British Journal of Clinical Pharmacology, 2008.
• Cormio L, et al. Oral L-citrulline supplementation improves erection hardness in men with mild erectile dysfunction. Urology, 2011.
• Siervo M, et al. Inorganic nitrate and beetroot juice supplementation reduces blood pressure in adults. Journal of Nutrition, 2013.
• Schulman SP, et al. L-arginine therapy in acute myocardial infarction (VINTAGE MI). JAMA, 2006.

This article is for information only and is not medical advice. Supplements are not intended to diagnose, treat, cure or prevent any disease.