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Head-to-head evidence comparison — which supplement is right for you?
Arginine vs Soy Protein: Arginine has the stronger overall evidence (7.5 vs 6.5/10); they're alternatives for support heart health — the best pick depends on your goals. Take the 60-second quiz for a pick tailored to your goals.
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
Mostly mechanism / observational
Top outcomes
Shared outcomes (1)
Outcomes where both Arginine and Soy Protein 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
20-40g per serving for muscle (aim ~2-3g leucine); ~25g/day is the level associated with cholesterol lowering
any
Soy protein isolate
30-60 minutes
During exercise
2-4 weeks
Immediate
6-12 weeks
4-12 weeks
Acute
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).
No Difference Between the Effects of Supplementing With Soy Protein Versus Animal Protein on Gains in Muscle Mass and Strength in Response to Resistance Exercise.
Int J Sport Nutr Exerc Metab (2018) · Meta analysis · n=266
Nine studies (266 participants); soy vs whey/animal protein with resistance training ≥6 weeks
Meta-analysis of the effects of soy protein intake on serum lipids.
N Engl J Med (1995) · Meta analysis
38 controlled clinical trials; mean soy intake ~47g/day
Effects of high-quality protein supplementation on cardiovascular risk factors in individuals with metabolic diseases: A systematic review and meta-analysis of randomized controlled trials.
Clin Nutr (2024) · Meta analysis
63 RCTs across soy, milk, whey, and casein protein
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.
AI-estimated from published studies. Interpret as directional guidance.
Arginine has a higher evidence score (7.5/10 vs 6.5/10) and wins in 2 of 3 categories.
For support heart health, Arginine has a higher relevance score (62 vs 50).
No known interactions between Arginine and Soy Protein have been documented in our database. However, always consult a healthcare provider before combining supplements.
The right pick depends on your goals. Answer a few quick questions for a personalised recommendation — or dig into the full evidence on each.