Arginine Versus Citrulline: Which is superior to Nitric Oxide Synthesis? by Jerry Brainum 10/21

 

 

When Applied Metabolics was initially published in print form in the late 90s, I wrote about a then-obscure substance called Nitric Oxide or NO. Although unknown in bodybuilding and sports, NO was causing a sensation in medicine because it appeared to provide a myriad of effects in both health and disease. Before NO was formally identified, which led to the three scientists who succeeded in doing so winning the Nobel Prize for medicine 1998, a substance was known to be produced in blood vessels that when released inside the lining of the vessels, produced an immediate and pronounced dilation effect, thereby greatly increasing blood flow. But it proved nearly impossible to identify because it was an ephemeral gas that appeared within seconds and disappeared in about 4 seconds. Trying to isolate it was akin to catching a ghost. For want of a better term, the gaseous substance was called the "endothelial relaxation factor," since it appeared to be produced in the endothelium or the lining of blood vessels. Thanks to the research of the three scientists who won the Nobel prize, this mysterious factor was finally identified as nitric oxide (NO). This work was considered so significant that NO was awarded the "Molecule of the year" award in 1998, although it never showed up to accept the award. But what else would you expect from a ghost?

In my article published in Applied Metabolics that same year, 1998, I suggested that based on its potent vasodilation effects, NO could have some useful applications in sports and exercise. For example, the dilation of blood vessels that results from the release of NO would improve blood flow into the muscle. This would have the effects of not only increasing the feeling of a pronounced muscle pump during exercise but also improve the flow of blood into the muscle for increased delivery of oxygen and nutrients. That, in turn, would tend to reduce feelings of muscular fatigue, allowing more intense training, while the increased delivery of nutrients into the muscle, such as amino acids, might play a role in increased muscle protein synthesis, which would translate into a greater degree of muscular hypertrophy or muscle size gains. Later research showed that NO does play direct roles in promoting muscular hypertrophy, such as through the promotion of anabolic hormones such as testosterone and growth hormone, as well as directly influencing the hypertrophy process by helping to activate satellite cells, muscle stem cells involved in the repair and growth of muscles.

I suggested in my article that supplements that boost NO synthesis would likely turn out to popular among athletes and bodybuilders because of the effects on muscle related to NO release. Within 10 years, my prediction came true and since then countless types of food supplements purported to boost NO . . .