Overview
Conditionally essential amino acid and direct nitric oxide precursor.
- Nuts
- Seeds
- Meat
- Legumes
- L-Arginine HCl
- Arginine AKG
Mechanism of action
Substrate for nitric oxide synthase (NOS) producing NO; precursor for creatine and ornithine.
- · NO synthesis
- · Urea cycle
Effects on the body
Organ system effects
Improves endothelial function in some cohorts.
Evidence-based benefits
Improves erectile function (often with pycnogenol)
Moderate evidenceLowers BP modestly
Moderate evidencePotential side effects
- · GI upset
- · Diarrhea
- · Worsens herpes outbreaks
Drug interactions
Supplement interactions
None listed.
- Active herpes (HSV)Promotes viral replication; lysine antagonizes.
Dosing & bioavailability
Where to buy
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Scientific evidence (9)
L-Arginine: pharmacology, clinical evidence, and safety — narrative review
Examine.com Research Team
Curated narrative review of human and preclinical evidence for L-Arginine, including mechanism, typical dosing, and safety considerations.
Best-supported outcome: Improves erectile function (often with pycnogenol) (evidence: moderate). Additional outcomes and limitations summarized in the full profile.
PubMed: L-Arginine — Improves erectile function
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PubMed: L-Arginine — Lowers BP modestly
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PubMed: L-Arginine — randomized controlled trial
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PubMed: L-Arginine — meta-analysis
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PubMed: L-Arginine — pharmacokinetics
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PubMed: L-Arginine — safety adverse events
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PubMed: L-Arginine — dose response
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Google Scholar: L-Arginine — clinical evidence
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Cross-database citation index for L-Arginine as it relates to "clinical evidence".
Includes preprints, theses, and journal articles. Useful for tracking citation counts and follow-on work.