Are you taking large doses of l-arginine to increase your nitric oxide production? I hope not.
If you are, I have some bad news for you. It doesn’t work.
I have talked about nitric oxide many times before. It is one of the most critical oxygen-based molecules that you have in your body. Nitric oxide regulates blood pressure, blood vessel function, sexual function, and immune function.
So what does this have to do with l-arginine?
L-arginine is an amino acid. That means that it’s a component of the proteins in your diet. Your body uses l-arginine to form the enzyme that is responsible for producing nitric oxide. In that process, the l-arginine is converted into l-citrulline. L-citrulline is then converted in the kidney back into l-arginine for the process to continue making more nitric oxide. So, it seems perfectly natural to expect that when you take l-arginine as a supplement, your body will use it to make more nitric oxide. Not so fast, pardner.
L-arginine can also be processed in the liver into a waste product called urea. Recently, researchers studied nine healthy men and women. They gave all of them various doses of l-arginine. Then they used a special technique to determine how much of the l-arginine went into nitric oxide production and how much was converted into urea.
The results are pretty dismal for all those who had hoped that taking l-arginine by itself is a good way to increase nitric oxide production.
In every case, after the participants ingested and absorbed the l-arginine, 60% of it was immediately converted to urea in the liver. Of the remaining l-arginine that made it to the bloodstream, only around 2% went to nitric oxide production. So, is there a way to improve this situation? In fact, there are two ways.
One way is to take l-citrulline. Remember that when the body uses l-arginine to produce nitric oxide, the l-arginine is converted into l-citrulline. The l-citrulline is then converted back into l-arginine in the kidney. So, what would happen if you were to take l-citrulline all by itself?
Three years ago, researchers published the results of giving 12 young, healthy men a placebo pill and then measuring the output of nitric oxide in their breath. It did not increase at all. Then they repeated the experiment, and this time gave them 6 grams of l-citrulline instead of the placebo. This time, the nitric oxide levels increased by a whopping 20%. Not only that, but their blood levels of l-arginine also increased. So, it looks like taking l-citrulline is a more effective way to get the effects of l-arginine than actually taking l-arginine itself. Who would have guessed? But that is not the end of the story.
There is another way to increase your nitric oxide levels using a supplement. It’s called CircO2, which contains l-citrulline. Just take one lozenge per day. One particular study shows that within one hour, your nitric oxide levels will be higher and your blood pressure lower. I call that amazing.
How does it work? In a very ingenious and patented process. It works independently of l-arginine by causing nitrates and nitrites to be converted into nitric oxide.
So if you are taking l-arginine hoping to have the benefits of higher nitric oxide production, you can stop now. And instead take one CircO2 each day. You can further improve on that by taking 6 grams of l-citrulline once a day.
Yours for better health,
Frank Shallenberger, MD
REF:
Houston, M. and L. Hays. “Acute effects of an oral nitric oxide supplement on blood pressure, endothelial function, and vascular compliance in hypertensive patients.” J Clin Hypertens(Greenwich). 2014 July;16(7):524-9.
Mariotti, F., K.J. Petzke, D. Bonnet, et al. “Kinetics of the utilization of dietary arginine for nitric oxide and urea synthesis: insight into the arginine-nitric oxide metabolic system in humans.”?Am J Clin Nutr.?2013 May;97(5):972-9.
Theodorou AA, Zinelis PT, et al. Acute L-Citrulline Supplementation Increases Nitric Oxide Bioavailability but Not Inspiratory Muscle Oxygenation and Respiratory Performance. Nutrients. 2021 Sep 22;13(10):3311