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Head-to-head evidence comparison — which supplement is right for you?
Arginine wins 2 of 3 categories. Both are solid choices — the best pick depends on your specific goals.
Verdict
Probably helps
11 of 19 studies with measurable effects showed benefit.
Top outcomes
Verdict
Likely helps
3 of 4 studies with measurable effects showed benefit.
Top outcomes
Shared outcomes (1)
Outcomes where both Arginine and Ornithine have evidence — compare verdict strength side-by-side.
3-6g daily
30-60 minutes before exercise, Divided doses throughout the day for cardiovascular benefits
L-Arginine powder or capsules
2-6g daily
Before exercise for fatigue reduction, Before bed for sleep support
L-Ornithine HCl
30-60 minutes
During exercise
2-4 weeks
Immediate
During prolonged exercise
Hours post-exercise
1-2 weeks
Immediate
Nutritional interventions for preventing and treating pressure ulcers
The Cochrane database of systematic reviews (2024) · Meta analysis · n=7920
Compared to standard diet, protein supplements may result in little to no difference in pressure ulcer incidence (protein 21 per 1000, standard diet 28 per 1000; RR 0.75, 95% CI 0.49 to 1.14; 4 studies, 4264 participants; low-certainty evidence).
Comparative Effects of Different Nutritional Supplements on Inflammation, Nutritional Status, and Clinical Outcomes in Colorectal Cancer Patients: A Systematic Review and Network Meta-Analysis
Nutrients (2023) · Meta analysis · n=2841
Glutamine was superior in decreasing tumor necrosis factor-α (MD -25.2; 95% CrI [-32.62, -17.95]), whereas combined omega-3 and arginine supplementation was more effective in decreasing interleukin-6 (MD -61.41; 95% CrI [-97.85, -24.85]).
Nutritional interventions for treating foot ulcers in people with diabetes
The Cochrane database of systematic reviews (2020) · Meta analysis · n=629
It is also uncertain whether arginine, glutamine and β-hydroxy-β-methylbutyrate supplement increases the proportion of ulcers healed at 16 weeks compared with placebo (RR 1.09, 95% CI 0.85 to 1.40).
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.
Based on meta-analysis showing mean reductions of 5.39 mmHg systolic and 2.66 mmHg diastolic. Effects are modest and may not be clinically significant for all individuals. GI side effects increase notably above 6g.
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.
Arginine has a higher evidence score (9/10 vs 8.5/10) and wins in 2 of 3 categories.
Both Arginine and Ornithine score equally (65) for improve endurance.
No known interactions between Arginine and Ornithine have been documented in our database. However, always consult a healthcare provider before combining supplements.