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Info on L-arginine


Originally Posted by BossaNova

Is there any validity to the estrogen level increase? Practically every bodybuilding publication I’ve read puts Arginine in it’s essential supps list.

I’ve never heard anything about it before, so I am eagerly await some kind of source for the claim.

I’d like to see the source aswell - manboobs really aren’t on my checklist.

Start: 6.7" BPEL 4.7" MSEG

Now: 7.3" BPEL 5.0" MSEG

Goal: 8.0" BPEL 5.5" MSEG

I was looking for information about how/when to take l-arginine, and came across this pretty good site:

In particular, the site boosts the ‘theory’ that taking doses about 30 mins before bed will boost GH and many other good things… check it out…

I’ve hear L-Arginine can be helpful when you want to increase your load.. Can someone explain to me how it works or if it works or if I have been miss informed

1st May 2007 - EL 5.11 inches, ie 13 cm

It’s said to be the “biggest scam” of supplements. That’s what I have found. Here are some links and here is a little background on the author;

“David J. Barr is a Doctoral student at the prestigious University of Texas Medical Branch amino acid metabolism lab, which is almost single handedly responsible for our pre and post workout nutrition information. An accomplished varsity strength coach, he has certifications with the NSCA and USA Track and Field. In addition to his work for NASA at the Johnson Space Center, David’s research has involved everything from the cellular basis of muscle breakdown to work on critically ill catabolic patients.”


Hemodilators: Theory and Practice

The hemodilator (or blood vessel dilator) products saturating the market are purported to stimulate blood flow and subsequently enhance nutrient delivery to muscles, resulting in increased size and strength. As you may know, these products contain little more than the amino acid arginine, something that’s been on the supplement market for years and years. Basically, arginine supplementation is claimed to stimulate the synthesis of the hemodilator nitric oxide (NO) in our blood vessels.

The existing theory looks like this:

Arginine -> Nitric Oxide -> Vasodilation -> Nutrient Delivery -> Muscle Growth and Strength

Now there’s nothing inherently wrong with arginine. In fact, it’s an important amino acid. It’s just not the amino acid to really help your gains — more on that later.

New research has been revealed since the first T-Nation article on these types of supplements was published. Now we can focus on that which is directly applicable to us: studies on healthy adults.

Sick Over Arginine

The whole hemodilator theory is relatively simple. Arginine is the precursor for NO synthesis and it’s been shown that high dose arginine infusion directly into the bloodstream can lead to vasodilation in healthy fasted humans (17). Unfortunately, high doses can lead to decreases in total body water and sodium (4). And even a dose as low as 10 grams has been associated with gastric upset when consumed orally (26,14).

Researchers involved in a third study demonstrating oral arginine-induced GI distress actually had to reduce the quantity originally given so the trials could be completed effectively (29). Despite the reduction to seven grams an hour for three hours (for a 200 pound man), the researchers reported: “All of our subjects reported mild intestinal cramping and diarrhea that lasted for approximately five hours.”

But wait, it gets worse! This arginine dose still had no significant effect on glycogen storage following exercise (29)! Because oral arginine only has 70% bioavailability, and up to 50% of this can be broken down to ornithine, taking arginine tablets or powder is impractical for research (6, 9). This is why arginine is usually infused directly into the blood via peripheral IV for scientific studies, and even then an impractical dose of 30 grams of this amino acid is common.

In fact, one study compared infusions and oral dosing. The researchers found that six grams of arginine had no effect via either route of administration, while it took a 30 gram infusion to cause vasodilation (6). So, it takes a 30 gram IV dose to get results. If we were to get these results from an oral dose, we’d have to take 43 grams because only 70% of it is bioavailable (I.e. 30 / .7 = 43).

Now if 10 grams can cause gastric upset, then the 43 gram oral dose (with bioavailability taken into account) makes me more than a little uneasy.

Arginine: A No Go for NO

If you think that this lack of effect is an isolated incident, other studies investigating high oral doses of arginine and NO induced blood flow have shown no effect when 21 grams (7 g 3x/d) were used (1). Two additional studies where 20 grams per day were taken for 28 days also showed no effects (11,12).

At first, this complete lack of effect was a little surprising considering that arginine is the precursor for nitric oxide synthesis. But upon closer inspection, natural arginine levels are far in excess of what should activate the enzyme responsible for NO production — an effect known as the arginine paradox (21).

In yet another study, a six day, arginine free diet had no effect on nitric oxide synthesis. This indicates that arginine isn’t limiting for NO production, and it’s regulation is far more complicated than supplement companies would have us believe (9).

Of course, the whole rested and fasted thing doesn’t apply to you, so let’s see what happened when exercise was involved. This next noteworthy study used 10 grams of arginine along with 70 grams of carbohydrates in subjects who either performed resistance training or cycling exercise (26). The results? There were no changes in blood flow or glucose uptake compared to placebo, regardless of which mode of exercise was used. This is significant because it directly contradicts the claims of the supplement manufacturers.

For those who are more skeptical, or perhaps just brainwashed by flashy advertising, you’re probably not happy with studies using pure arginine. Oh no, it has to be special arginine, like the ones used in the popular products, before you’ll believe any results. Fine, let’s look into the science and crack that nut.

The Acid Test

While it’s important to understand the evidence behind normal arginine supplementation, many would argue that it doesn’t apply to the original nitric oxide-stimulating supplement, NO2. This is because the aforementioned product contains arginine alpha-ketoglutarate, not simply arginine. The theory is that alpha ketoglutarate (AKG) somehow makes this supplement “work.” Okay, that’s cool, let’s see what science has to say. ..


Pt.2 :


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