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Definition: "An ergogenic aid is any substance or phenomenon that enhances performance "
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11.02.2015 |
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Better NO boosters contain a combination of L-arginine and L-citrulline
Sports supplements with amino acids designed to boost the concentration of nitrogen monoxide [NO] work better if they contain not just L-arginine or L-citrulline but a combination of the two. Researchers at the Japanese manufacturers Kyowa Hakko Bio discovered this when they did an experiment on rabbits.
L-Arginine
Despite this, L-arginine supplementation doesn't have spectacular effects in athletes, probably because the liver breaks L-arginine down fast. Some supplements manufacturers get round this problem by using L-arginine's metabolite, L-citrulline, in their products instead. The liver cannot break down L-citrulline, but enzymes in the body can convert L-citrulline into L-arginine.
Study
They gave rabbits water containing a hefty dose of L-arginine. The human equivalent would be about 12 grams.
A second group of rabbits was given an identical dose of L-citrulline, and a third group was given a mixture containing equal amounts of L-arginine and L-citrulline. The human equivalent of the doses that the third group of rabbits got would be about 6 grams L-arginine and 6 grams L-citrulline. Obscenely high, indeed, but the Japanese were after proof of principle.
Results
The mixture of L-citrulline and L-arginine resulted in a bigger rise in the concentration of NO in the blood of the animals than the rise of the amino acids separately. The artery widening effect of NO is due to the activation of the enzyme cGMP. The concentration of this enzyme also rose by a greater amount when the rats were given the combined amino acids than when they were given them separately.
Circles = L-arginine; squares = L-citrulline; triangles = mixture.
Conclusion
Source:
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