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Head-to-head evidence comparison — which supplement is right for you?
L-Citrulline wins 2 of 3 categories. Both are solid choices — the best pick depends on your specific goals.
Verdict
Likely helps
9 of 11 studies with measurable effects showed benefit.
Top outcomes
Verdict
Probably helps
3 of 5 studies with measurable effects showed benefit.
Top outcomes
3-6g (or 6-8g citrulline malate)
30-60 minutes before exercise, Or split doses throughout day
L-Citrulline powder (pure form)
2-6g daily
Before exercise for fatigue reduction, Before bed for sleep support
L-Ornithine HCl
1-2 weeks
24-48 hours post-exercise
30-60 minutes
With doses >10g
During prolonged exercise
Hours post-exercise
1-2 weeks
Immediate
Absence of Effects of L-Arginine and L-Citrulline on Inflammatory Biomarkers and Oxidative Stress in Response to Physical Exercise: A Systematic Review with Meta-Analysis
Nutrients (2023) · Meta analysis · n=1080
We observed no difference between pre- vs. post-exercise for oxidative stress (subtotal = -0.21 [CI: -0.56, 0.14], p = 0.24, and heterogeneity = 0%.
Effects of Citrulline or Watermelon Supplementation on Body Composition: A Systematic Review and Dose-Response Meta-Analysis
Nutrients (2025) · Meta analysis
Overall, CIT supplementation had no substantial effects on body mass index (BMI), body weight, fat mass (FM), waist circumference (WC), body fat percentage (BFP), and fat-free mass (FFM).
Effect of food sources of nitrate, polyphenols, L-arginine and L-citrulline on endurance exercise performance: a systematic review and meta-analysis of randomised controlled trials
Journal of the International Society of Sports Nutrition (2021) · Meta analysis
No effect on exercise performance following consumption of foods rich in L-citrulline was identified (SMD=-0.03, p=0.24).
Comparative Efficacy of Treatment Options for Minimal Hepatic Encephalopathy: A Systematic Review and Network Meta-Analysis
Clinical gastroenterology and hepatology : the official clinical practice journal of the American Gastroenterological Association (2020) · Meta analysis · n=1563
In a meta-analysis of data from 25 trials, we found rifaximin and lactulose to be most effective for reversal of minimal HE in patients with cirrhosis.
Safety assessment of L-ornithine oral intake in healthy subjects: a systematic review
Amino acids (2025) · Systematic review
The main observed adverse events were gastrointestinal disorders.
Efficacy of L-ornithine L-aspartate for minimal hepatic encephalopathy in patients with cirrhosis: A meta-analysis of randomized controlled trials
Arab journal of gastroenterology : the official publication of the Pan-Arab Association of Gastroenterology (2024) · Meta analysis · n=292
LOLA has significant beneficial effects on reversal of MHE and prevention of OHE in patients with cirrhosis compared with placebo or no intervention.
Meta-analysis showed significant reduction in muscle soreness 24h post-exercise but effect size was modest. Studies primarily used citrulline malate form.
Evidence specific to L-ornithine L-aspartate form in cirrhosis patients. Meta-analysis of 292 patients showed significant benefit vs placebo. GI adverse events noted as main side effect. Limited applicability to healthy populations.
AI-estimated from published studies. Interpret as directional guidance.
L-Citrulline has a higher evidence score (6/10 vs 5/10) and wins in 2 of 3 categories.
For improve endurance, L-Citrulline has a higher relevance score (85 vs 65).
No known interactions between L-Citrulline and Ornithine have been documented in our database. However, always consult a healthcare provider before combining supplements.