Nitric Oxide Supplements for Blood Pressure: Beetroot vs. Citrulline vs. Arginine

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Nitric oxide supplements for blood pressure — usually beetroot or dietary nitrate, L-citrulline, or L-arginine — are marketed as an easy way to relax blood vessels and nudge readings down. The honest summary: dietary nitrate has the most consistent evidence for modest blood-pressure reductions, L-citrulline has reasonable support in middle-aged and older adults, and L-arginine is less reliable. [Norouzzadeh, 2025] [Luo, 2025]

None of them replaces guideline-based care, and all of them can be risky if you already take blood-pressure medicine, because the effects stack. [AHA/ACC, 2025] For most people, a food-first approach — nitrate-rich vegetables, regular movement, and good sleep — is still the safest starting point, with supplements treated as an optional, clinician-guided extra. If you want the bigger picture first, see our complete guide to nitric oxide for blood pressure.

The short version Best evidence: dietary nitrate (beetroot, leafy greens) — modest average drops of roughly 3–4 mmHg systolic across trials.Promising: L-citrulline, with measurable but smaller effects in older adults.Less reliable: L-arginine — absorption and response vary widely. Most important: supplements are supportive at best, not a substitute for prescribed treatment. If you take BP medication, get clinician sign-off before adding any vasodilating supplement.

What counts as a “nitric oxide supplement”?

Nitric oxide (NO) itself is a short-lived gas your blood-vessel lining makes to help arteries relax, so you cannot bottle it directly. [Carlström, 2024] Products instead supply ingredients that feed the pathways your body uses to produce or signal NO. They generally fall into three groups:

• Dietary nitrate (often beetroot or greens) — converted by mouth bacteria to nitrite and then toward NO signaling through the nitrate–nitrite–NO pathway. [Lidder & Webb, 2013]
• L-citrulline — an amino acid the body can convert to arginine, supporting the enzyme pathway that makes NO.
• L-arginine — a direct precursor in that same enzyme pathway, but with less predictable absorption.

These are not interchangeable, and marketing often blurs the differences. Knowing which ingredient you are taking matters for both effectiveness and safety.

Which option has the best evidence for blood pressure?

For blood pressure specifically, dietary nitrate has the strongest and most consistent research trail. A 2025 systematic review and dose-response meta-analysis of 75 randomized trials found that dietary nitrate modestly lowered blood pressure, with systolic reductions on the order of about 3–4 mmHg and a dose-related pattern. [Norouzzadeh, 2025]

L-citrulline comes next. A 2025 meta-analysis of 15 randomized trials in middle-aged and older adults reported reductions of roughly 4 mmHg systolic and 2.5 mmHg diastolic, with the largest effects when citrulline was combined with arginine. [Luo, 2025] L-arginine on its own is the least reliable of the three, largely because much of an oral dose is broken down before it can act.

Put plainly: these are real but small average effects, more like a helpful nudge than a replacement for treatment. They also vary a lot between individuals.

Nitric Oxide Supplements for Blood pressure

Comparison at a glance

Option	How it works (simple)	Who it may suit	Common issues & cautions
Dietary nitrate (beetroot, greens)	Nitrate → nitrite → supports NO signaling via oral bacteria	Food-first people; those who tolerate beets and leafy greens	GI upset; beeturia (pink urine); blunted by strong antibacterial mouthwash
L-citrulline	Raises arginine availability for the NO-making enzyme pathway	Adults focused on circulation/exercise; some BP benefit in older adults	Can lower BP too far if stacked with meds or other vasodilators; GI upset
L-arginine	Direct precursor in the NO synthase pathway	Select, clinician-guided cases	Less consistent results; GI side effects; caution with herpes history and certain meds

Realistic expectations

Average blood-pressure changes from these supplements are modest — often a few mmHg — and not everyone responds. They work best as one part of a broader plan that includes nitrate-rich foods, activity, sleep, weight management and, when needed, medication. If your readings are high, the supplement is not the main lever; consistent measurement and guideline-based care are. [AHA/ACC, 2025] You can read more about the everyday lifestyle habits that support nitric oxide.

Dosing and timing (general guidance only)

This is an educational starting point, not a prescription. Research protocols differ, and the right approach depends on your health and medications, so treat any trial as something to do with your clinician’s awareness.

• Beetroot / nitrate products: often taken once daily; some people notice short-term effects within hours, but judge by trends over weeks, not single readings.
• L-citrulline: research doses vary and are sometimes split through the day; effects build over weeks. [Luo, 2025]
• L-arginine: doses vary widely and tolerance is inconsistent; many people get GI upset.

The key rule: if you already take blood-pressure medicine, do not stack multiple vasodilators without supervision — the combined drop can be too large.

Safety first: who should be cautious

“Natural” does not mean risk-free, and supplements are loosely regulated. Be especially careful — and talk to a clinician first — if any of these apply:

• You take blood-pressure medication (risk of blood pressure dropping too low).
• You have a history of fainting, dizziness, or very low blood-pressure readings.
• You have kidney disease or significant cardiovascular disease (discuss any change with your clinician).
• You use PDE5 inhibitors (e.g., for erectile dysfunction): combining them with nitrate-based strategies can cause a dangerous drop in blood pressure — a known, serious interaction with nitrate medications — so get medical advice first.
• You are pregnant or breastfeeding: use only under clinician guidance.

The mouthwash factor

If you are relying on dietary nitrate, your mouth matters. Friendly oral bacteria perform the first step of converting nitrate to nitrite. In small studies, frequent use of strong antibacterial mouthwash blunted this conversion and was linked to higher blood pressure in treated hypertensive adults. [Bondonno, 2015] [Joshipura, 2020] This does not mean “never use mouthwash” — but if you are using nitrate foods for blood-pressure support, heavy daily antibacterial rinsing may work against you. More detail is in our piece on antibacterial mouthwash and oral bacteria.

How to test a supplement the smart way

If you and your clinician decide to try one, run it like a simple experiment so you get a clear answer rather than a guess:

1. Take a 7-day baseline of home blood pressure first, measured at the same time each day. [AHA/ACC, 2025]
2. Change only one variable — a single supplement.
3. Start with the smallest reasonable dose.
4. Track your blood-pressure trend plus any symptoms daily for about two weeks.
5. If you feel dizzy or lightheaded, or your readings drop too far, stop and contact your clinician.

Learning to track your blood pressure at home correctly is what tells you whether anything is actually working.

What to track	How often	Why it matters
Blood-pressure trend	Daily or 4–5x/week	Trends beat single readings
Dose and timing	Daily note	Helps you spot patterns
Symptoms	As needed	Low BP can show as dizziness
Sleep and caffeine	Daily note	Major confounders

Label quality checklist

• Does the label state the exact dose of the active ingredient?
• Is it a single-ingredient product, or a “proprietary blend” that hides amounts?
• Is there third-party testing (for example USP or NSF)?
• Avoid stacking with other vasodilators unless your clinician approves.

If blood-pressure support is your main goal, food-first options plus herbs that may support healthy blood pressure are usually a gentler place to start than layering several supplements.

Health Disclaimer: This article is for general education only and is not medical advice, diagnosis, or treatment. It does not claim that any supplement cures, prevents, or treats high blood pressure or any other condition. If you have high blood pressure, heart disease, kidney disease, are pregnant or breastfeeding, or take prescription medication, talk with a qualified clinician before starting, stopping, or changing any treatment or supplement. Do not stop prescribed blood-pressure medication on your own. If you have severe symptoms such as chest pain, fainting, or a hypertensive crisis, seek emergency care immediately.

Frequently asked questions

References

1. Carlström M, Weitzberg E, Lundberg JO. Nitric Oxide Signaling and Regulation in the Cardiovascular System: Recent Advances. Pharmacol Rev. 2024;76(6):1038–1062.  → View source
2. Lidder S, Webb AJ. Vascular effects of dietary nitrate (as found in green leafy vegetables and beetroot) via the nitrate–nitrite–nitric oxide pathway. Br J Clin Pharmacol. 2013;75(3):677–696.  → View source
3. Norouzzadeh M, et al. Plasma nitrate, dietary nitrate, blood pressure, and vascular health biomarkers: a GRADE-assessed systematic review and dose-response meta-analysis of randomized controlled trials. Nutr J. 2025;24:47.  → View source
4. Luo P, et al. Does L-citrulline supplementation and watermelon intake reduce blood pressure in middle-aged and older adults? A systematic review and meta-analysis of randomized controlled trials. Clin Nutr ESPEN. 2025;69:653–664.  → View source
5. Bondonno CP, et al. Antibacterial mouthwash blunts oral nitrate reduction and increases blood pressure in treated hypertensive men and women. Am J Hypertens. 2015;28(5):572–575.  → View source
6. Joshipura K, et al. Over-the-counter mouthwash use, nitric oxide and hypertension risk. Blood Press. 2020;29(2):103–112.  → View source
7. 2025 AHA/ACC Guideline for the Prevention, Detection, Evaluation, and Management of High Blood Pressure in Adults. Hypertension. 2025.  → View source