SYS ONLINE
SUPPLEMENT_SCHOLAR
evidence · mechanism · dose
Supplements/Amino Acid

L-Citrulline

aka Citrulline malate

Arginine precursor with superior bioavailability for NO and pump-driven performance.

Athletic PerformanceLibido & Sexual HealthCardiovascular Health

Overview

Arginine precursor with superior bioavailability for NO and pump-driven performance.

Natural sources
  • Watermelon
Common forms
  • L-Citrulline
  • Citrulline malate (2:1)

Mechanism of action

Bypasses hepatic first-pass metabolism, converted to arginine in kidneys, raises plasma arginine more than arginine itself.

Pathways
  • · NO synthesis
  • · Urea cycle

Effects on the body

Increases
Plasma arginine
Increases
Nitric oxide
Decreases
Perceived exertion

Organ system effects

Skeletal Muscle

Improves training volume and reduces soreness.

Evidence-based benefits

Improves resistance training reps to failure

Moderate evidence

Improves erectile function in mild ED

Limited evidence

Potential side effects

Common
  • · GI upset (rare)
Rare
    Serious

      Drug interactions

      Nitrates / PDE5 inhibitors
      Additive hypotension.
      moderate

      Supplement interactions

      Pairs well with
      • Beta-alanine
        Endurance + pump synergy in pre-workouts.
      Avoid combining with

      No specific avoidances listed.

      Dosing & bioavailability

      Typical dose
      6–8 g citrulline malate or 3–6 g L-citrulline
      Timing
      30–60 min pre-workout

      Where to buy

      Affiliate-style search links to reputable retailers. We don't endorse specific brands — verify third-party testing (USP, NSF, Informed Sport) before purchase.

      Amino Acid
      L-Citrulline
      Amazon
      Wide selection · fast shipping
      Amino Acid
      L-Citrulline
      iHerb
      Global delivery · curated brands
      Amino Acid
      L-Citrulline
      Thorne
      Practitioner-grade · NSF tested

      Scientific evidence (9)

      Systematic reviewExamine.com Supplement Database · 2023

      L-Citrulline: pharmacology, clinical evidence, and safety — narrative review

      Examine.com Research Team

      Curated narrative review of human and preclinical evidence for L-Citrulline, including mechanism, typical dosing, and safety considerations.

      Key findings

      Best-supported outcome: Improves resistance training reps to failure (evidence: moderate). Additional outcomes and limitations summarized in the full profile.

      Open study
      Systematic reviewPubMed (NLM) · 1970

      PubMed: L-Citrulline — Improves resistance training reps to failure

      Live PubMed search

      Live results for "L-Citrulline Improves resistance training reps to failure" across the PubMed/MEDLINE peer-reviewed index.

      Key findings

      Opens current human and preclinical literature matching L-Citrulline and "Improves resistance training reps to failure". Filter by RCT, meta-analysis, or year on the results page.

      Open study
      Systematic reviewPubMed (NLM) · 1970

      PubMed: L-Citrulline — Improves erectile function in mild ED

      Live PubMed search

      Live results for "L-Citrulline Improves erectile function in mild ED" across the PubMed/MEDLINE peer-reviewed index.

      Key findings

      Opens current human and preclinical literature matching L-Citrulline and "Improves erectile function in mild ED". Filter by RCT, meta-analysis, or year on the results page.

      Open study
      Systematic reviewPubMed (NLM) · 1970

      PubMed: L-Citrulline — randomized controlled trial

      Live PubMed search

      Live results for "L-Citrulline randomized controlled trial" across the PubMed/MEDLINE peer-reviewed index.

      Key findings

      Opens current human and preclinical literature matching L-Citrulline and "randomized controlled trial". Filter by RCT, meta-analysis, or year on the results page.

      Open study
      Systematic reviewPubMed (NLM) · 1970

      PubMed: L-Citrulline — meta-analysis

      Live PubMed search

      Live results for "L-Citrulline meta-analysis" across the PubMed/MEDLINE peer-reviewed index.

      Key findings

      Opens current human and preclinical literature matching L-Citrulline and "meta-analysis". Filter by RCT, meta-analysis, or year on the results page.

      Open study
      Systematic reviewPubMed (NLM) · 1970

      PubMed: L-Citrulline — pharmacokinetics

      Live PubMed search

      Live results for "L-Citrulline pharmacokinetics" across the PubMed/MEDLINE peer-reviewed index.

      Key findings

      Opens current human and preclinical literature matching L-Citrulline and "pharmacokinetics". Filter by RCT, meta-analysis, or year on the results page.

      Open study
      Systematic reviewPubMed (NLM) · 1970

      PubMed: L-Citrulline — safety adverse events

      Live PubMed search

      Live results for "L-Citrulline safety adverse events" across the PubMed/MEDLINE peer-reviewed index.

      Key findings

      Opens current human and preclinical literature matching L-Citrulline and "safety adverse events". Filter by RCT, meta-analysis, or year on the results page.

      Open study
      Systematic reviewPubMed (NLM) · 1970

      PubMed: L-Citrulline — dose response

      Live PubMed search

      Live results for "L-Citrulline dose response" across the PubMed/MEDLINE peer-reviewed index.

      Key findings

      Opens current human and preclinical literature matching L-Citrulline and "dose response". Filter by RCT, meta-analysis, or year on the results page.

      Open study
      Systematic reviewGoogle Scholar · 1970

      Google Scholar: L-Citrulline — clinical evidence

      Live Scholar search

      Cross-database citation index for L-Citrulline as it relates to "clinical evidence".

      Key findings

      Includes preprints, theses, and journal articles. Useful for tracking citation counts and follow-on work.

      Open study
      Educational use only. This profile is not medical advice. Consult a qualified healthcare professional before starting any supplement, especially if you take prescription medication or have a chronic condition.