Blood Flow & Pump
L-Citrulline / Citrulline Malate
Raises arginine and nitric oxide levels more effectively than arginine itself. Improves blood flow, reduces fatigue, and enhances work capacity.
Effective Dose
6–8g citrulline (or 8–10g C. Malate)
per clinical evidence
Evidence Level
Moderate
Blood Flow & Pump
Mechanism
Nitric oxide via arginine pathway
primary action
Best For
Pre-workout
Endurance, Pump
This profile is for informational purposes only and does not constitute medical advice. Consult a qualified healthcare professional before starting any supplementation, especially if you have pre-existing conditions or take medications.
What Is L-Citrulline / Citrulline Malate?
L-citrulline is an amino acid found abundantly in watermelon. After absorption, it is converted to arginine in the kidneys — bypassing the gut degradation that limits oral arginine's effectiveness. Elevated arginine feeds eNOS (endothelial nitric oxide synthase), increasing NO production and vasodilation.
How It Works: The Science
Citrulline enters the urea cycle and is converted to arginine by argininosuccinate synthase and lyase. This indirect route raises plasma arginine more effectively than direct arginine supplementation. Higher arginine availability increases nitric oxide synthesis, dilating blood vessels, reducing oxygen cost of exercise, and improving blood flow to working muscle.
Primary Mechanism
Nitric oxide via arginine pathway
Evidence-Based Benefits
Dosage Guide
Effective Dose
6–8g citrulline (or 8–10g C. Malate)
6–8g pure L-citrulline or 8–10g citrulline malate (2:1 ratio), taken 30–60 minutes pre-workout. Citrulline malate delivers ~5.6g citrulline per 8g serving. Effects on NO are dose-dependent — sub-5g doses show weaker results in the literature.
Safety Profile & Side Effects
Well tolerated with no significant adverse effects at recommended doses. May cause mild GI discomfort if taken on an empty stomach. Not recommended alongside erectile dysfunction medications (PDE-5 inhibitors) due to additive blood pressure lowering.
Who Should (and Shouldn't) Take It
Most useful for gym athletes wanting better pumps and endurance, and for any sport requiring sustained submaximal output. Stack with beetroot extract or agmatine for additive NO effects.
Frequently Asked Questions
Related Ingredients
Medical Disclaimer
Ingredient profiles are for informational purposes only and do not constitute medical advice. Consult a qualified healthcare professional before starting any supplementation, especially if you have pre-existing conditions or take medications. Full disclaimer →