L-Citrulline Dosage Calculator
A non-essential amino acid that raises arginine and nitric oxide more effectively than arginine itself. Increases blood flow, delays muscle fatigue, and meaningfully improves both endurance and strength performance.
What is L-Citrulline?
L-citrulline is a non-proteinogenic amino acid found naturally in watermelon. Unlike direct arginine supplementation, citrulline bypasses first-pass hepatic metabolism and is converted to arginine in the kidneys, producing sustained plasma arginine elevation (120–170% increase) and consequently higher nitric oxide (NO) synthesis than arginine supplementation at equivalent doses. NO-mediated vasodilation reduces peripheral vascular resistance, increases oxygen and nutrient delivery to working muscle, and delays the onset of muscle acidosis by enhancing lactate clearance. A 2010 RCT (Pérez-Guisado & Jakeman, Journal of Strength and Conditioning Research) showed that 8 g citrulline malate 60 minutes before a bench press protocol increased repetitions to failure by 52.92% compared to placebo, and reduced post-exercise muscle soreness by 40% at 24 and 48 hours. Meta-analyses consistently confirm 1–3% improvements in endurance time trials and significant increases in resistance training volume.
How to Take L-Citrulline
**Pure L-citrulline:** 0.1–0.15 g/kg body weight (6–10 g for most adults) taken 45–60 minutes pre-workout. **Citrulline malate (2:1 ratio):** 8 g pre-workout — the form used in most resistance training RCTs. Citrulline malate may provide additional ergogenic benefit from the malate (a Krebs cycle intermediate that reduces ammonia accumulation), though this contribution is debated. Choose pure citrulline for endurance and cardiovascular benefits; citrulline malate for resistance training volume.
Timing Recommendations
Take 45–60 minutes before training for peak plasma nitric oxide availability during the workout. Post-workout citrulline can support recovery by maintaining elevated blood flow to damaged muscle tissue during the repair window, though pre-workout remains the primary evidence-supported window. On rest days, citrulline has no established benefit and is not needed.
Potential Side Effects & Safety
Very well tolerated. GI discomfort (bloating, nausea) occasionally occurs at doses > 10 g on an empty stomach — take with a light snack or split into two doses. Mild hypotension possible when combined with phosphodiesterase inhibitors (Viagra, Cialis) — contraindicated combination. Theoretical reduction in blood pressure relevant for hypotensive individuals.
Who should avoid L-Citrulline?
Individuals on nitrate-containing medications or phosphodiesterase-5 inhibitors (sildenafil, tadalafil) — additive vasodilation risk. Individuals with hypotension should monitor blood pressure. No contraindication in pregnancy at dietary amounts, but supplemental doses lack safety data.
Best Stacks with L-Citrulline
L-citrulline + beta-alanine + caffeine forms the most evidence-supported pre-workout performance stack. Adding creatine addresses a complementary energy system (phosphocreatine vs. NO-mediated blood flow). Beetroot powder stacks synergistically — both elevate NO via different pathways (citrulline via arginine conversion; beetroot via dietary nitrate-to-nitrite-to-NO pathway).
Scientific References
All dosage recommendations are grounded in peer-reviewed research.
- 1Citrulline malate enhances athletic anaerobic performance and relieves muscle soreness
Journal of Strength and Conditioning Research · 2010
- 2A systematic review of L-citrulline supplementation on endurance and strength performance
European Journal of Sport Science · 2020
L-Citrulline Dosage Calculator
Personalized to your body weight
Enter your weight above to see your personalized dosage
Safety notes
- Take 45–60 minutes before training — not post-workout.
- Do NOT combine with Viagra, Cialis, or any PDE5 inhibitor — dangerous additive hypotension.
- GI discomfort at doses > 10 g? Take with a small snack or split the dose.
- Citrulline malate 2:1 and pure L-citrulline are not equivalent — check your label.
This calculator provides general guidance only. Always consult a qualified healthcare professional before starting any supplement.