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L-Arginine — Frequently Asked Questions

This content is for informational purposes only and does not constitute medical advice. Consult your healthcare provider before starting any supplement. Full disclaimer

Frequently Asked Questions

Is L-Arginine or L-Citrulline better for nitric oxide?

L-Citrulline is generally more effective at raising plasma arginine levels because it bypasses first-pass metabolism in the gut and liver. A study by Schwedhelm et al. (2008) showed oral citrulline increased plasma arginine more effectively than arginine itself. For sustained NO production, citrulline is preferred; arginine may still be useful for acute dosing.

Can L-Arginine help with erectile dysfunction?

Yes, moderately. A 2019 meta-analysis of 10 RCTs found L-arginine (1.5-5 g/day) significantly improved erectile function scores. It works by increasing NO, which is essential for penile blood flow. Combining arginine with Pycnogenol (pine bark extract) showed enhanced effects in the Prelox study. It is less potent than PDE5 inhibitors but may help mild cases.

Does L-Arginine lower blood pressure?

Yes. A meta-analysis of 11 RCTs showed L-arginine at 4-24 g/day reduced systolic blood pressure by an average of 5.4 mmHg and diastolic by 2.7 mmHg. Effects are most pronounced in those with elevated blood pressure. If you take antihypertensive medications, consult your doctor as effects may be additive.

Full L-Arginine Guide

References

  1. (). Effect of oral L-arginine supplementation on blood pressure: a meta-analysis of randomized, double-blind, placebo-controlled trials. American Heart Journal. DOI
  2. (). The Potential Role of Arginine Supplements on Erectile Dysfunction: A Systemic Review and Meta-Analysis. Journal of Sexual Medicine. DOI
  3. (). Pharmacokinetic and pharmacodynamic properties of oral L-citrulline and L-arginine. British Journal of Clinical Pharmacology. DOI