Updated: September 13 2013
What Is It?Arginine is an amino acid. It has two forms, D and L isoforms. The L-form is one of the 20 most common natural amino acids. This supplement research review will be about L-arginine.
Sources of Arginine
1. Animal sources: cottage cheese, ricotta, milk, yogurt, whey protein drinks, beef, pork, gelatin, chicken, turkey, quail, lobster, salmon, shrimp, snails, and tuna.
2. Plant sources: wheat flour, buckwheat, granola, oatmeal, peanuts, coconut, pecans, cashews, walnuts, almonds, Brazil nuts, hazelnuts, pinenuts, pumpkin, sesame, sunflower, chickpeas, and cooked soybeans
3. In the human body: arginine is synthesized from citrulline
What Does Research (Human Studies) Say?
1. Increases plasma L-arginine; small but reliable effect. [1-6]
2. Decreases blood pressure (BP); small and unreliable effect. [1,4,6,7,8]
3. Increases blood flow; small and unreliable effect; due to increased synthesis of nitric oxide, but there is limited evidence of increased NO-synthesis with L-arginine. [2,5,6,8,9]
4. Increases nitric oxide (NO) synthesis; small and unreliable effect. [3,5,6,7,9,13]
5. Increases anaerobic running capacity (anaerobic physical performance); small and unreliable effect. [7]
6. Increases endothelial function (vascular response); small and unreliable effect; seen in people with impaired glucose tolerance or diabetes mellitus type 2. [8,13]
7. Decreases concentrations of endothelin-1; small effect. [13]
8. Increases insulin secretion and insulin sensitivity; small effect; may be due to the secretagogue-effect of arginine; prolonged use may regenerate pancreatic beta-cells in those with impaired glucose tolerance. [4]
9. Decreases fat mass; small effect; it may be seen after a prolonged use in people with impaired glucose tolerance; this does not mean that L-arginine can be used as a fat burner
in healthy people. [4]
10. Increases lean mass; small effect; it may be seen after a prolonged use in people with impaired glucose tolerance; this does not mean that L-arginine can be used as a fat burner
in healthy people. [4]
11. Increases adiponectin level and adiponectin:leptin ratio; small effect; seen in people with impaired glucose tolerance. [13]
Conclusion
There is limited evidence that L-arginine supplementation is beneficial.
Verdict: Do not add to your supplement stack
Recommended Dosage (Used in the Studies)
1. Pre-workout supplement (PWO): 3-6 grams / daily; 10 g may lead to diarrhea; the limit is 20 g. [10]
Where Can You Buy This Supplement?
Amazon.com, Bodybuilding.com
Side Effects of This Supplement
1. Tested (20 grams) without adverse effects (except diarrhea) and may be safe; limited evidence though. [10]
2. Diarrhea (osmotic diarrhea) may occur at doses above 10 grams; occurs in L-arginine supplementation, but not D-arginine. [11-12]
References
1. L-arginine-induced vasodilation in healthy humans: pharmacokinetic-pharmacodynamic relationship
2. L-arginine supplementation in peripheral arterial disease: no benefit and possible harm
3. No effect of short-term arginine supplementation on nitric oxide production, metabolism and performance in intermittent exercise in athletes
4. Effect of a long-term oral l-arginine supplementation on glucose metabolism: a randomized, double-blind, placebo-controlled trial
5. Pharmacokinetic and pharmacodynamic properties of oral L-citrulline and L-arginine: impact on nitric oxide metabolism
6. Effects of 7 days of arginine-alpha-ketoglutarate supplementation on blood flow, plasma L-arginine, nitric oxide metabolites, and asymmetric dimethyl arginine after resistance exercise
7. Acute L-arginine supplementation reduces the O2 cost of moderate-intensity exercise and enhances high-intensity exercise tolerance
8. Hemodynamic and vascular response to resistance exercise with L-arginine
9. Restoring vascular nitric oxide formation by L-arginine improves the symptoms of intermittent claudication in patients with peripheral arterial occlusive disease
10. Risk assessment for the amino acids taurine, L-glutamine and L-arginine.
11. Adverse Gastrointestinal Effects of Arginine and Related Amino Acids
11. Adverse Gastrointestinal Effects of Arginine and Related Amino Acids
12. Growth hormone responses to varying doses of oral arginine.
13. Beneficial effects of a long-term oral L-arginine treatment added to a hypocaloric diet and exercise training program in obese, insulin-resistant type 2 diabetic patients
14. The effect of oral L-arginine supplementation on fasting glucose, HbA1c, nitric oxide and total antioxidant status in diabetic patients with atherosclerotic peripheral arterial disease of lower extremities
15. A study of growth hormone release in man after oral administration of amino acids
13. Beneficial effects of a long-term oral L-arginine treatment added to a hypocaloric diet and exercise training program in obese, insulin-resistant type 2 diabetic patients
14. The effect of oral L-arginine supplementation on fasting glucose, HbA1c, nitric oxide and total antioxidant status in diabetic patients with atherosclerotic peripheral arterial disease of lower extremities
15. A study of growth hormone release in man after oral administration of amino acids
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