L-Arginine Supplements May Be Useless

Few supplements received as much attention lately as L-arginine, the naturally occurring amino acid, of which manufacturers claim it improves workout results through an increase in nitric oxide and growth hormone. A new study found that for anyone reasonably fit, it does just about nothing.

What Is L-Arginine?

L-arginine is a precursor of nitric oxide, a substance that has been shown to increase blood flow, which – if you believe some  supplement manufacturers – leads to increased workout performances.

I already talked about this in my review of N.O.-Xplode 2.0 and if you read it, you know that already there I doubted that taking a supplement to increase your nitric oxide level would make any difference.

Testing L-Arginine Scientificially

Now Scott Forbes, a doctoral student in exercise physiology at the University of Alberta, Canada, did something I’m very thankful for and what most supplement companies never consider, despite having the funds to do so: He scientifically tested different doses of L-arginine and what effect they had.

He took 14 healthy, athletic men, made sure they were not using any other nutritional supplements and analyzed their consumption of  carbohydrates, protein and fat. To put all on a level playing field, they were then required to follow a set diet, that regulated food and water intake, and finally gave them either a low or high dose of L-arginine. Then he examined how these influenced the blood level of L-arginine, markers of nitric oxide and growth hormone – the last playing an important role in cell production and therefore too having an impact on increases in muscle mass.

No Effect If You Already Are Fit

The results? Both the high and low doses raised L-arginine concentrations in the blood at rest, and both were equally effective in doing so. But neither promoted a significant increase in nitric oxide or growth hormone.

It is therefore very likely that L-arginine will do nothing for you, if you already are active and have a balanced nutrition.

Did you use one of these supplements and experienced a positive effect? Please let me know!

Picture courtesy of “Bruce“.