✓ No active regulatory warningsFDA MedWatch, EMA EudraVigilance, WHO VigiBase, WADA Prohibited List · 2026-05-29
📰Read the full Nitric Oxide Boosters evidence review on GMJ News →Complete clinical article, references and updates on news.gmj.ge. This page is the structured safety summary.⚠ Patient on sildenafil/tadalafil adding NO booster — additive hypotension [1]
⚠ Patient taking arginine when citrulline is superior — citrulline raises arginine more [1]
⚠ Patient using mouthwash before beetroot supplementation — blocks nitrate conversion [1]
⚠ Pre-workout blend with 'proprietary NO blend' — likely underdosed; check individual amounts [1]
ℹ️ Not obtained from food. Not applicable — this is a blend; dietary contribution depends on its declared ingredients.
🔬 Lab interpreter
Recommended test
Blood pressure
Blood pressure
Reference range / target
Per individual goals
Per individual goals
Modest BP reduction expected (~4 mmHg SBP) [1].
Full lab monitoring ↓⚕ For professionals — confirm ranges against your local laboratory.
Clinical verdict
NO boosters are a legitimate sports/cardiovascular supplement category. Three evidence-based options: (1) L-citrulline 3–6 g/day (best oral NO precursor — raises arginine MORE than arginine itself); (2) beetroot juice 500 mL, 2–3 hours pre-exercise (multiple RCTs); (3) L-arginine (outdated due to poor bioavailability). CRITICAL: avoid mouthwash before beetroot (kills oral bacteria needed for nitrate→nitrite); screen for PDE5 inhibitor interaction [1].
1 How much do I need?
👤 Adults: Specific dosage data under clinical review
👴 Elderly: Specific dosage data under clinical review
🤰 Pregnancy: See guidance
Beetroot as food: safe. L-arginine studied for preeclampsia. Pre-workout blends: avoid [1].
👦 Pediatric: See guidance
No established pediatric indications for NO boosters. Beetroot juice as food is safe for children [1].
🏃 Athletes: Standard dose
⚖️ Obesity: Standard dose
Fat-soluble compounds may require dose adjustment in obesity.
🩺 Renal: Consult specialist
Dose adjustment may be needed in renal impairment.
🌱 Vegan: Standard dose
How to take
🍽 Timing: Pre-exercise: 2–3 hours for beetroot; 60 min for citrulline. BP: BID [1].
💊 With food: Beetroot: on its own. Citrulline: with or without food [1].
🚫 Avoid: Mouthwash before beetroot. Underdosed proprietary blends. Combining with PDE5 inhibitors without guidance [1].
2 Which form?
| Form | Bioavailability | Vegan | Cost |
|---|---|---|---|
| ['L-Citrulline (or citrulline malate)', 'preferred', '6–8 g/day citrulline malate (or 3–6 g L-citrulline). Most evidence-based NO precursor [1].'] | Standard | Check label | |
| ['Beetroot juice/powder (dietary nitrate)', 'evidence-based', '500 mL juice or 6.4 mmol nitrate (400–500 mg). 2–3 hours before exercise [1].'] | Standard | Check label | |
| ['L-Arginine', 'outdated', '3–6 g/day. Poor oral bioavailability (~20% first-pass metabolism). Largely superseded by citrulline [1].'] | Standard | Check label | |
| ['Pre-workout blends', 'combination', 'Often contain citrulline + beetroot + other ingredients. Check individual doses — proprietary blends may under-dose [1].', 'orange'] | Standard | Check label |
3 Common questions
Why is citrulline better than arginine? ▼
L-arginine undergoes extensive first-pass metabolism in the liver (~80% is degraded before reaching systemic circulation). L-citrulline bypasses this: it is absorbed intact, travels to the kidneys, and is converted to arginine there — actually raising plasma arginine levels MORE than arginine supplementation itself. This is one of the most counterintuitive facts in supplement science [1].
How long before exercise should I take beetroot juice? ▼
2–3 hours before. This is the time needed for dietary nitrate to be absorbed, converted to nitrite by oral bacteria, and further reduced to NO. Note: mouthwash and antibacterial mouthrinse BLOCK the nitrate-nitrite conversion (oral bacteria are required) — avoid mouthwash before beetroot-based supplementation [1].
Do pre-workout NO formulas actually work? ▼
Many are underdosed. The effective dose of citrulline malate is 6–8 g — but proprietary blends may hide the actual amount. Check the label for individual ingredient doses. A product listing 'proprietary NO blend 3,000 mg' is likely underdosed [1].
Can NO boosters help erectile dysfunction? ▼
L-citrulline (1.5 g/day) improved erection hardness in 1 small RCT of mild ED, but the effect was inferior to PDE5 inhibitors (sildenafil). NO boosters are a reasonable first-line supplement approach for mild ED, but not a substitute for PDE5 inhibitors in moderate-severe ED [1].
4 Clinical evidence
Strong
Beetroot juice (dietary nitrate): multiple RCTs show improved time-to-exhaustion (3–5%) and reduced oxygen cost of submaximal exercise. Most consistent for recreational athletes; elite athletes show less benefit (already high baseline NO) [1]. HIGH
Moderate
L-Citrulline: 3–6 g/day improved exercise repetitions to fatigue in several small RCTs and reduced blood pressure (SBP −4 mmHg) in a meta-analysis. Erectile function: L-citrulline 1.5 g/day improved hardness scores in 1 small RCT of mild ED (inferior to PDE5 inhibitors) [1]. L-Arginine: 3 g/day improved flow-mediated dilation in a meta-analysis but oral bioavailability concern limits clinical utility [1]. MODERATE
Insufficient
5 Safety, toxicity & adverse events
Absolute contraindications
✕ Concurrent nitrates or PDE-5 inhibitors — additive hypotension (depends on the arginine/citrulline/nitrate content)
Relative
⚠ Not a single substance — contraindications depend on the declared ingredients; see L-Arginine, L-Citrulline and nitrate (beetroot) entries
⚠ Low blood pressure or antihypertensive therapy
⚠ Herpes (HSV) — if arginine-based
🚩 Red flags
● Patient on PDE5 inhibitor + NO booster — syncope risk [1]
● Patient on nitroglycerin + NO booster — dangerous hypotension [1]
● Patient alarmed by red urine after beetroot — beeturia, harmless [1]
6 Interactions
Drug interactions
PDE5 inhibitors (sildenafil, tadalafil) Major
Mechanism: Both increase NO-cGMP pathway signaling [1].
Effect: Additive vasodilation → hypotension → syncope [1].
Action: Use with caution; start with low NO booster dose. Avoid if already hypotensive [1].
Nitroglycerin / Organic nitrates Major
Mechanism: Same NO-cGMP pathway [1].
Effect: Severe hypotension [1].
Action: AVOID combination [1].
Supplement synergies
Creatine · 5 g creatine + 6 g citrulline malate
Complementary exercise performance mechanisms: NO (blood flow) + creatine (phosphocreatine resynthesis) [1].
Complementary exercise performance mechanisms: NO (blood flow) + creatine (phosphocreatine resynthesis) [1].
Caffeine · 200 mg caffeine + 6 g citrulline malate
Standard pre-workout combination. Caffeine (central stimulation) + NO (peripheral blood flow) [1].
Standard pre-workout combination. Caffeine (central stimulation) + NO (peripheral blood flow) [1].
7 Regulatory
United States (FDA): Individual ingredients (citrulline, arginine, beetroot) available as dietary supplements. Pre-workout blends: variable quality and regulation [1].
Sports: Beetroot/nitrate is not banned by WADA. Considered a legitimate sports nutrition strategy [1].
8 Cite this page
Vancouver: Pkhakadze G. Nitric Oxide Boosters — safety profile [Internet]. Tbilisi: PHIG; 2026 [cited 2026 Aug 15]. Available from: https://supplement.ge/ingredients/nitric-oxide-boosters/
APA 7th: Pkhakadze, G. (2026). Nitric Oxide Boosters — Safety profile. Public Health Institute of Georgia. https://supplement.ge/ingredients/nitric-oxide-boosters/
📋 Editorial information
Author: Prof. G. Pkhakadze, MD, MPH, PhD
Institution: Public Health Institute of Georgia (PHIG)
Affiliation: David Tvildiani Medical University (DTMU)
First published: January 2026
Last reviewed: 2026-05-29
Next review: February 2027
References: 4 cited sources
COI: SupplementIndex receives no funding from supplement manufacturers. All content independently authored by PHIG.
Process: Systematic literature review
📄 License & reuse
Published under Creative Commons Attribution 4.0 International (CC BY 4.0). You may share and adapt for any purpose with attribution.
Pkhakadze G. "Nitric Oxide Boosters — Safety Profile." SupplementIndex, PHIG, 2026. https://supplement.ge/ingredients/nitric-oxide-boosters/ CC BY 4.0.
GP
Prof. G. Pkhakadze, MD, MPH, PhD
Professor of Public Health · Head of Department, DTMU
Editor-in-Chief, Georgian Medical Journal (ISSN 3088-4322)
Chair, Public Health Institute of Georgia · UEMS Public Health Section
Educational and public health purposes. CC BY 4.0. Consult your healthcare provider before starting any supplement. Corrections: info@accreditation.ge. Publisher: PHIG