This specific product had several studies performed on it, and they were presented at the International Society of Sports Nutrition conference in the summer of 2004. While the findings do not yet come from peer reviewed publications, they yield important information about the efficacy, or lack thereof, of this supplement.

The first study examined the blood levels of arginine and "time released arginine" (following a four gram supplementation with each) to determine whether the latter enhanced the duration of elevated blood arginine levels (18). The reasoning for this study is due to the claim that NO2 has time-release technology, resulting in "perpetual pumps."

Unfortunately for the company, blood arginine levels were nearly all quite similar, and at times 30% lower, in the time-release trial compared to the pure arginine trial! The reason for the lower levels of the former group remains elusive, but could be due to a decreased absorption by the gut, an increased uptake by tissues, or a half dozen other fates for arginine (see 4). Not surprisingly, there was nothing resembling a "time release" effect.

The second study of interest evaluated the effects of NO2 on body composition, muscle strength and endurance (8). For eight weeks, subjects took either 12 grams of NO2 or placebo and underwent a resistance training protocol. At the end of the time period, subjects between groups had no differences in either muscle mass or body fat percentage.

Interestingly, the NO2 group threw an average of 19 pounds onto their bench 1RM, while the placebo group added less than a six pound mean. Does it seem strange to anyone else that this supplement alone supposedly added an average of more than 13 pounds to bench press 1RM over placebo without a concomitant change in muscle mass? This would indicate that the changes are strictly neural in origin, which gets quite complicated and goes beyond the scope of this article.

I'll briefly mention that while nitric oxide itself can have a negative effect on the force of muscle contraction (25), this effect has yet to be shown in humans, and doesn’t warrant serious consideration for our purposes. More importantly, all of the scientific evidence indicates that it's not even possible for us to consume high enough levels of arginine to effectively increase nitric oxide levels! Since this unpublished study is already gracing the advertisements for this supplement, we need to examine the results in a little more detail.

If the subjects in the above study were untrained, they would all add a significant amount of strength without changes in muscle mass within the first several weeks of working out. In this case, these rapid neural adaptations would be expected in both groups, but wouldn't explain how arginine seemingly tripled the improvement in the nervous system activation.

However, since the subjects were in fact trained, the situation is even more puzzling. Unlike novice trainees, strength increases in trained individuals tend to be more a result of muscle growth, which means that there should've been some changes in lean body mass accompanying the other gains. There wasn't.

I would've been impressed, albeit skeptical, by a three or four pound gain over the placebo group on bench press 1RM, but an average of 13 pounds?! Looking at it another way, this means an average gain of two and a half pounds on bench 1RM each week, and this progress is maintained for a whole eight weeks on the same program!

If this trend continued for all exercises, which it presumably does, everyone with these results could easily become a competitive powerlifter. Although such improvements might be theoretically possible, you must remember that these fantastic results were achieved on a training program and diet that normally leads to a mere six pound addition to bench press. Furthermore, to have such incredible strength gains throughout every muscle group, without even the slightest trend for improved muscle growth, demands questioning.

Considering the other research which showed no effect on blood flow and no time release effect, the results just don’t fit. Whether it be improper group selection, outliers in the data, or measurement error, the results presented remain questionable.

With my objective experience as a strength coach, researcher and bodybuilder, I don't believe these results to be possible. Having said that, this article is merely intended to give you the facts that you won’t get anywhere else, and allow you make up your own mind.

Let’s sum of the results of this study and others:

• One group used oral arginine in this study, but oral arginine supplementation doesn't affect blood flow.

• The arginine group used "time release" arginine, but so-called time release arginine is not actually time released.

• The trained individuals in the NO2 group got stronger without increasing muscle growth, but trained individuals get stronger mostly due to muscle growth.

• The training program and diet alone yielded a six pound increase in bench 1RM, yet four grams of NO2 taken three times a day tripled strength gains on the same program.

In short, something just isn't right.

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