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Sports Nutrition

Everything You Need to NO

Just say NO. NO news is good news. Getting to NO you.

Magazines that, like this one, address the pursuit of healthy lean mass have exhausted every possible pun involving the letters NO. While that may make it tough for us to continue to come up with catchy headlines, it means that NO one (we can’t help ourselves) should be unaware of the benefits of NO or, more formally, nitric oxide. But just in case you somehow don’t NO (last one, promise) what the fuss is about — or just couldn’t get past the horrible puns — we’ve assembled this primer to introduce you to the compound that pretty much guarantees improvements in mass. You won’t even NO what hit you (sorry).

High vs. Wide

The first thing you need to know about nitric oxide (NO) is that it’s not the same as nitrous oxide. Yes, they’re both gases, but one will get you giggling in the dentist’s chair, while the other will bump your pump in the gym.

Nitric oxide is produced naturally in the body, and it is instrumental in just about all the body’s functions, from transmitting messages between nerve cells and aiding the immune system in fighting off intruders to controlling blood flow and regulating the function of just about all the body’s organs.

It is so critical to health, in fact, that Science magazine named it “molecule of the year” in 1992, and in 1998, the scientists who discovered its influence on the cardiovascular system were awarded the Nobel Prize in physiology/medicine.

It is just that influence that interests us. As it turns out, nitric oxide signals the smooth muscles that line the blood vessels to relax, which dilates the vessels themselves. That affects everything from blood pressure to erections, though for our purposes, the most critical factor is the fact that wider blood vessels allow for more blood flow to muscle tissue. Because blood carries water, nutrients, oxygen and other critical elements to muscles, getting more blood through means getting more of all that good stuff in there. So not only does that guarantee that your muscles will be bathed in exactly what they need to speed recovery and improve muscle growth, but the added fluid pressing on the muscle cell walls encourages growth in and of itself.

Furthermore, new research presented at the 2009 meeting of the International Society of Sports Nutrition found that subjects who took a NO-boosting supplement and engaged in weight training for four weeks experienced a significant increase in muscle strength in addition to mass. Another study, this one published in the American Journal of Physiology, found that NO enhances lipolysis, which is the release of fat cells from fat stores into the blood stream to be burned.

All About Arginine


Clearly, there are ample reasons to ensure that your NO levels are up there. But sadly, NO doesn’t come in pill form and is not available in stores. In order to increase NO levels, therefore, you need to take the amino acid arginine, which the body breaks down to create NO. Furthermore, arginine is known to blunt levels of a hormone called growth-hormone-inhibiting hormone, which, uh, inhibits growth-hormone production. Shocker, right? Anyway, responsible for higher growth-hormone levels and higher NO levels, arginine is certainly among a bodybuilder’s best friends.

But while arginine is easily found — supplement store shelves are laden with it because everyone knows how beneficial NO is to bodybuilders — picking which type to take is not so simple. Here is a quick rundown of some of the most common types.


This is as basic as it gets. However, some scientists argue that arginine by itself is not absorbed as well by the body as when it’s bonded to other compounds. Which is why we have things like…


Yes, it’s a mouthful, but the alpha-ketoglutarate part is just a compound that the body will convert into the amino acid glutamine. Because the intestines love glutamine (and the intestines are where supplement absorption occurs), there’s some evidence that having that glutamine precursor attached to the arginine makes it absorb easier.


Another mouthful, this one has the potential to further muscle growth. The KIC part of the equation is converted by the body to something called beta-hydroxy beta-methylbutyrate (HMB), which prevents catabolism and enhances muscle growth. KIC can also aid recovery during and after workouts because it assists in the removal of ammonia from the body.


No mouthful and no fancy acronyms for this compound, which consists solely of arginine bonded to malic acid, a compound linked to energy production.


This one is arginine bonded to an acid and an alcohol, but don’t get excited. No intoxication will result from consuming this particular form of arginine, but improved uptake might. It’s thought that the ester group helps arginine cross cell membranes, from the intestines to the muscle tissue, resulting in better absorption.


Taking arginine is certainly the most popular and expeditious way of increasing NO levels in the body, but that doesn’t mean that it should be the only way. Many NO-boosting supplements include one or more of the following compounds precisely because they assist arginine in bumping up NO. Either opt to take one of those products or add some of these to your regimen. (See page 46 for a quick-glance chart).


Like arginine, citrulline is an amino acid that can be used to create NO in the body. However, it’s beneficial to take it with arginine because while arginine can get hoarded by the intestines (yes, they need it, too), citrulline can slip right through and stock NO levels. In fact, a study published in the British Journal of Clinical Pharmacology found that taking citrulline raised levels of arginine and NO better than taking arginine.


Easily synthesized by the body, histidine is not among the nine essential amino acids. However, supplementing with it can do wonders for both NO levels. Rather than directly increasing NO production, histidine increases the activity of nitric oxide synthase (NOS), the enzyme responsible for breaking arginine apart and creating NO. The more NOS you have, the more arginine your body will be able to use.


This potent antioxidant vitamin also works on the back-end, using its free-radical-fighting powers to limit the breakdown of NO.


Also an antioxidant, this extract from the French maritime pine tree works the way histidine does, kicking NOS into gear to increase the amount of arginine that’s broken down into NO.


When a study published in, of all places, the journal Nitric Oxide compared the NO-protecting abilities of powerful antioxidants like Concord grape juice, blueberry juice, red wine, and even vitamins C and E, it found that pomegranate juice reigned supreme, proving to be 300 times better at preventing NO from sustaining oxidative damage than anything else.


Arginine and NO boosters in general are known as preworkout supplements, and with good reason. The most ideal time to take them is between 30 and 60 minutes before you hit the gym. The idea is to expand those blood vessels and get that blood pumping so that your muscles will be well-served with nutrients and that your energy levels will be boosted in time for your workout. Most people also find that the pump that arginine provides makes them look even more impressive in the gym’s mirrors.

But that’s not the only time to ingest arginine. You should also take it after workouts in order to make sure that your blood vessels remain dilated to help your muscles recover, by ushering beneficial nutrients in and speeding the removal of all the bad stuff created by pushing out rep after rep. Furthermore, you’ll recall that arginine has a beneficial effect on growth-hormone levels, which ideally should be high around workout time to help maximize muscle growth.

In addition, take arginine before breakfast to promote anabolism after your overnight fast and again before bed to help recovery while you sleep. We provide you a chart to guide your intake, aptly titled “Arginine: Your Daily Guide,” on this page. With that, we hope we’ve left NO nitric-oxide-related questions unanswered. (OK, now that’s the last pun.)


Follow this handy schedule, remembering it’s always best to take arginine on an empty stomach to improve absorption.

MORNING Awake: 3 to 5 grams of arginine 30 to 60 minutes later: breakfast

PREWORKOUT 90 minutes out: 3 to 5 grams of arginine 30 to 60 minutes out: preworkout protein and carbs

POSTWORKOUT Just racked your last weights: 3 to 5 grams of arginine 30 minutes later: postworkout protein and carbs

BEDTIME 90 minutes out: 3 to 5 grams of arginine 30 to 60 minutes out: bedtime protein and healthy fats


We talked about how and when to take arginine, but if you’re interested in supplementing with any of its little helpers, this guide will help you figure out the details.