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Nitric Oxide Precursor

amino acids

Nitric oxide precursors, primarily L-arginine and L-citrulline, are amino acids that enhance the production of nitric oxide in the body, a critical signalling molecule for vascular function. These compounds improve blood flow, endothelial health, and oxygen delivery to tissues throughout the body.

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Benefits

Enhanced blood flow and circulation
Improved endothelial function
Better oxygen delivery to muscles
Reduced blood pressure
Enhanced exercise performance and recovery
Improved erectile function

Dosage

Typical Dose

5-10g daily

Upper Limit

15g daily

Timing

30-60 minutes before exercise or split into two doses

Forms & Bioavailability

L-Citrulline

Superior bioavailability; converts to L-arginine in kidneys; more stable than L-arginine

L-Arginine

Moderate bioavailability; directly stimulates nitric oxide synthase but may be degraded by arginase

Citrulline Malate

Enhanced bioavailability with added malic acid; supports ATP production

Side Effects

Gastrointestinal distress and bloating
Headaches
Dizziness
Nausea at high doses
Potential herpes simplex reactivation (L-arginine)

Interactions

May enhance effects of blood pressure medications
Can interact with phosphodiesterase-5 inhibitors (e.g., sildenafil)
May potentiate vasodilatory effects of other supplements

Research Summary

Research demonstrates that nitric oxide precursors improve vascular function, blood pressure regulation, and exercise performance in both athletic and clinical populations. Studies show L-citrulline particularly effective for endothelial dysfunction and hypertension, whilst both compounds enhance blood flow and oxygen utilisation. Evidence supports their use for cardiovascular health and exercise capacity, though individual responses vary.

The Bottom Line on Nitric Oxide Precursor

Nitric Oxide Precursor is well-researched with strong evidence supporting its primary benefits.It is most commonly used for enhanced blood flow and circulation and improved endothelial function. As with any supplement, individual results vary. Start with the lower end of the dosage range and assess for 4-8 weeks before adjusting.

About Our Research

This profile is compiled from peer-reviewed research published on PubMed, the NIH Office of Dietary Supplements, and established nutritional science databases. Dosages reflect clinically-studied amounts from human trials where available. We update profiles as new research emerges. This is not medical advice — consult a healthcare professional before supplementing.

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Disclaimer: This information is for educational purposes only and is not medical advice. Always consult a healthcare professional before starting any supplement, especially if you have existing health conditions or take medication.

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