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    L-Citrulline (and Citrulline Malate)New

    Supplement
    Amino Acids
    5/10 Evidence

    A non-essential amino acid that raises plasma arginine more efficiently than arginine itself, used for nitric-oxide-mediated vascular support, modest blood-pressure lowering, and (as citrulline malate) strength endurance.

    Mechanism of Action

    Orally ingested citrulline bypasses first-pass gut and liver arginase metabolism and is converted to arginine in the kidney, sustaining plasma arginine and endothelial nitric oxide synthase (eNOS)-derived nitric oxide, supporting vasodilation; malate may additionally support TCA-cycle ATP production during exercise.

    Dosing Protocol

    Recommended

    6g L-citrulline per day (or 6-8 g citrulline malate 40-60 min pre-workout)

    Standard starting dose based on research

    Therapeutic Range

    3

    Minimum

    to

    9

    Maximum

    g L-citrulline per day (or 6-8 g citrulline malate 40-60 min pre-workout)

    Divided doses with or without food for blood pressure; citrulline malate 40-60 minutes before training for performance

    Cycling Protocol

    No cycling required; blood-pressure effects need weeks of daily use and fade after discontinuation

    Dosages are general guidelines. Individual requirements vary based on body weight, health status, and specific goals. Start with lower doses and adjust based on response.

    Benefits

    Primary Benefits

    • Modest reduction in systolic blood pressure
    • Endothelial function / nitric oxide support
    • Strength-endurance support (reps to failure) with citrulline malate

    Secondary Benefits

    Possible reduction in post-exercise muscle soreness
    Possible support for erectile function in mild ED (limited evidence)

    Safety Information

    Contraindications

    Do not use if any of the following apply:

    • •Hypotension or taking nitrate medications without clinician guidance
    • •Recent myocardial infarction (arginine pathway caution)
    • •Pregnancy and breastfeeding (insufficient data)

    Drug/Supplement Interactions

    May interact with the following. Consult a healthcare provider before combining:

    Antihypertensives — additive blood-pressure lowering
    Nitrates and PDE5 inhibitors (sildenafil, tadalafil) — additive vasodilation and hypotension
    Other nitric oxide boosters (arginine, beetroot nitrate)

    Potential Side Effects

    Some users may experience:

    GI discomfort or nausea at doses above 10 g (rare below 9 g for L-citrulline)
    Lightheadedness if blood pressure is already low

    This is not a complete list of interactions or side effects. Individual responses vary. Always start with the lowest effective dose and monitor your response. Report any adverse effects to your healthcare provider.

    Quality Markers

    Look for these specific quality indicators when sourcing this compound:

    • Labeled as L-citrulline (free form) or citrulline malate with stated ratio (2:1 preferred)
    • Third-party tested for purity
    • Avoid proprietary blends that hide the citrulline dose

    Trusted Certifications

    NSF Certified
    USP Verified
    GMP Certified
    ConsumerLab Approved

    Note: Supplement quality varies dramatically between brands. Cheap supplements often contain fillers, incorrect doses, or contaminants. Investing in quality products from reputable manufacturers is essential for safety and efficacy.

    Evidence Profile

    Evidence Score

    5/10

    Moderate Evidence

    Some clinical trials with positive results, emerging research

    Classification:
    Moderate — a systematic review and meta-analysis found a pooled systolic blood-pressure reduction of about -4.1 mmHg (95% CI -7.9 to -0.3) at 3-9 g/day over 1-17 weeks, with diastolic benefit mainly at 6 g/day or more; a meta-analysis of citrulline malate (about 8 g, 40-60 minutes pre-exercise) found roughly 6% more repetitions to failure, but acute performance trials are inconsistent and a 2025 study found no ergogenic effect on muscle oxygenation or ventilation; no hard cardiovascular outcome trials exist Evidence

    Evidence Scale

    8-10

    Strong

    5-7

    Moderate

    1-4

    Emerging

    PHS
    671
    / 1000
    T3
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