Remedy Routes
    L-ArgininetoErectile Function(limited evidence)
    Outcome
    Limited
    Effectiveness 2/5

    L-Arginine for Erectile Function

    L-arginine is a direct nitric oxide precursor, but oral bioavailability is poor; trials show small, inconsistent benefits except at high doses or combined with PDE5 inhibitors.

    Overview

    L-arginine is a direct nitric oxide precursor, but oral bioavailability is poor; trials show small, inconsistent benefits except at high doses or combined with PDE5 inhibitors.

    Verdict

    Mixed evidence

    Citrulline raises arginine levels more effectively than arginine itself — prefer citrulline.

    How It Works

    Arginine is the substrate for nitric oxide synthase producing NO, the mediator of penile smooth-muscle relaxation. First-pass metabolism limits oral arginine bioavailability.

    Dosing & Protocol

    Typical dose

    Recommended dose
    3–5 g/day (citrulline preferred)
    Expected timeframe
    4–8 weeks.

    Protocol

    dose
    3–5 g
    notes
    Realistically, citrulline 3 g is the better choice for the same pathway.
    timing
    empty stomach
    duration
    4–8 weeks

    Evidence

    What the studies say

    A meta-analysis found high-dose arginine (2.8–5 g/day) improved subjective ED measures versus placebo in some trials, but heterogeneity is high and quality low. Combination with tadalafil showed additive effects in one RCT.

    Investigation of a complex plant extract for mild to moderate erectile dysfunction in a randomized, double-blind, placebo-controlled, parallel-arm study

    Score: 6/10
    2010
    rct
    n=124

    Ledda A, Belcaro G, Cesarone MR +2 more

    a formulation of pine bark extract and l-arginine aspartate

    View source

    Improvement of erectile function with Prelox: a randomized, double-blind, placebo-controlled, crossover trial

    Score: 5/10
    2008
    crossover
    n=50

    Stanislavov R, Nikolova V, Rohdewald P

    a combination of L-arginine aspartate and Pycnogenol (Prelox)

    View source

    Clinical assessment of a supplement of Pycnogenol® and L-arginine in Japanese patients with mild to moderate erectile dysfunction

    Score: 5/10
    2012
    rct

    Aoki H, Nagao J, Ueda T +5 more

    Pycnogenol® 60 mg/day, L-arginine 690 mg/day and aspartic acid 552 mg/day

    View source

    Efficacy of L-arginine and Pycnogenol ® in the treatment of male erectile dysfunction: a systematic review and meta-analysis

    Score: 7/10
    2023
    meta_analysis
    n=184

    Tian Y, Zhou Q, Li W +3 more

    the combination of PAL may have a significant effect on improving sexual function in patients with mild to moderate ED

    View source

    The Potential Role of Arginine Supplements on Erectile Dysfunction: A Systematic Review and Meta-Analysis

    Score: 8/10
    2019
    meta_analysis
    n=540

    Rhim HC, Kim MS, Park YJ +3 more

    arginine supplements with dosage ranging from 1,500 to 5,000 mg significantly improved ED compared with placebo or no treatment (odds ratios, 3.37 [1.29, 8.77], P = .01, I2 = 44)

    View source

    Safety

    Caveats

    GI upset at high doses. Do not combine with nitrates or use post-heart-attack without physician approval.

    Less likely to help if

    Most users — citrulline outperforms it for the same mechanism; men with significant vascular ED need medical therapy.

    Medical Disclaimer

    The information provided on this website is for educational and informational purposes only and is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition or before starting any supplement regimen.

    Individual results may vary. The statements on this website have not been evaluated by the Food and Drug Administration. Products and information are not intended to diagnose, treat, cure, or prevent any disease.