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Head-to-head evidence comparison — which supplement is right for you?
Caffeine wins 1 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
22 of 25 studies with measurable effects showed benefit.
Top outcomes
3-6g daily
30-60 minutes before exercise, Divided doses throughout the day for cardiovascular benefits
L-Arginine powder or capsules
100-200mg
Morning, 30-60 minutes before exercise
Pill/capsule for precise dosing
30-60 minutes
During exercise
2-4 weeks
Immediate
15-45 minutes
30-60 minutes
30-60 minutes
30-60 minutes
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).
Effect of Acute Caffeine Intake on the Fat Oxidation Rate during Exercise: A Systematic Review and Meta-Analysis
Nutrients (2020) · Meta analysis · n=2020
A subsequent meta-analysis was performed using the random effects model to calculate the standardized mean difference (SMD).
The effects of caffeine intake on weight loss: a systematic review and dos-response meta-analysis of randomized controlled trials
Critical reviews in food science and nutrition (2019) · Meta analysis · n=606
Thirteen RCTs with 606 participants were included in the meta-analyses.
Effect of Caffeine and Nitrates Combination on Exercise Performance, Heart Rate and Oxygen Uptake: A Systematic Review and Meta-Analysis
Nutrients (2024) · Meta analysis · n=95
The meta-analysis revealed that caffeine and nitrates supplementation (CAF+nitrates) did not enhance performance in time trials (TTs) over the CAF alone (g = -0.06; 95% CI = -0.46 to 0.35; p = 0.78) or nitrates alone (g = 0.29; 95% CI = -0.12 to 0.70; p = 0.17).
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.
Based on multiple meta-analyses showing 3-6mg/kg optimal dosing. Performance benefits plateau around 200-300mg with increased jitteriness at higher doses.
AI-estimated from published studies. Interpret as directional guidance.
Caffeine has a higher evidence score (9.5/10 vs 9/10) and wins in 1 of 3 categories.
For athletic performance, Caffeine has a higher relevance score (90 vs 65).
No known interactions between Arginine and Caffeine have been documented in our database. However, always consult a healthcare provider before combining supplements.