Nitric Oxide Supplements (Bodybuilding and Athletic
Performance) Review Article
Do Nitric Oxide
Supplements Really Work? Find Out If Nitric Oxide Supplements Really Build
Muscle or Improve Performance.
Medically reviewed and
edited by Tod Cooperman, M.D.
Initially Posted:
11/11/2011
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Table of Contents
What Is Nitric Oxide?
Nitric
oxide has been generating a lot of buzz lately in both research labs and weight
rooms. Not to be confused with nitrous oxide or "laughing
gas," nitric oxide (NO) is a different gas that plays important roles
throughout the body. Among other things, it's a vasodilator that tells the
blood vessels to relax, a crucial step for encouraging blood flow. Recent
research suggests that regular exercise may help bolster the supply of NO,
which might be a large reason why workouts improve circulation and lower the
risk of heart disease.
What Are Nitric Oxide
Supplements?
Many people in the weight-training crowd see NO as a natural
shortcut to greater strength and bigger muscles. The idea is that anything that
boosts blood flow to the muscles will also boost performance and results.
People interested in a quick NO fix have turned to dietary supplements that
claim to increase the supply of the gas NO. Most of these products contain
L-arginine, an amino acid that helps fuel the enzyme (NO synthase) that
produces NO. While other ingredients may be included in NO supplements, there
is little to no research supporting their effect the production of NO. NO
supplements include products like naNO
Vapor, Nitric Stack, Nitrix, NO
Fury, and NOX-3. Dramatic claims made on some NO products or
websites selling them include:
·
Harnesses the power of nitric oxide to get you incredibly pumped
beyond belief.
·
Contains a unique blend of arginine that will deliver massive
muscle pumps and extreme muscle hardness and fullness after your very first
dose!
·
Amplified nitric oxide release that leads to muscle growth
activation.
·
Transforms the 2-hour or less window of "pumped
perfection" into a physique-altering phenomenon that lasts the entire day.
Do Nitric Oxide Supplements
Really Work?
There is no doubt that nitric oxide plays a vital role in
circulation. But even though some bodybuilders swear by the results of
"nitric oxide" supplements, it's not clear that taking large doses of
L-arginine or other amino acids orally significantly increases production of
nitric oxide in everyone. The research studies published on nitric oxide
supplements in athletes so far haven't been promising. A 2009 study of
well-trained male athletes found that giving 6 grams of L-arginine supplementation
for three days raised their serum arginine levels but had no effect on nitric
oxide production or performance of intermittent anaerobic exercise (Liu, J Nutr Biochem
2009). In that study, nitric oxide production did increase during
exercise, but no more so with L-arginine than placebo. A 2011 study of eight
healthy young men published in the Journal of Nutrition found no evidence that
a beverage containing 10 grams of L-arginine improved blood flow to the muscles
or did anything to speed muscle buildup after weight lifting (Tang, J Nutr 2010).
A 2010 study including three different commercially available "nitric
oxide" supplements published in the Journal of the International Society
of Sports Nutrition found that none of the supplements (powders given in a
mixture with water 30 minutes prior to exercise) significantly improved weight-lifting
performance or muscle "pump" (the feeling that muscles were bigger,
fuller, and harder) in resistance-trained men (Bloomer, J Int Soc Sports Nutr 2010). The supplements also did not raise
biological indicators of nitric oxide in the blood or oxygen in muscles. The
products each listed L-arginine within a proprietary blend of other ingredients
but did not specify the specific amount of L-arginine, like many NO supplements
on the market.
Nitric oxide supplements may not be the answer for big muscles or for elite
athletes, but there's still some hope that they can improve exercise
performance in certain individuals. A 2010 study by researchers at UCLA
published in the Journal of the International Society of Sports Nutrition found
that a dose of Niteworks (from
Herbalife), a supplement containing 5.2 grams of a blend of L-arginine and L- citruline, increased the time that older male cyclists
(aged 50 to 73 years) could work out before reaching the anaerobic threshold,
the point at which lactic acid starts building up in muscles (Chen, J Int Sports Nutri, 2010). Niteworks includes large doses of vitamins C
and E, based on the assumption that these antioxidants may prevent nitric oxide
inactivation by oxygen free radicals. Another study in 2010 by British
researchers published in the Journal of Applied Physiology found that a beverage
containing L-arginine improved the stamina of healthy, recreationally active
men (Bailey, J Appl Physiol 2010).
Compared to taking a placebo beverage, drinking a beverage containing 6 grams
of L-arginine seemed to permit an extra two minutes or so of intense exercise
before reaching exhaustion.
As noted in ConsumerLab.com's
Review of L-Arginine Supplements,
several studies also suggest that L-arginine supplements may be helpful in
people with cardiovascular conditions such as angina or atherosclerosis.
However, L-arginine may also increase the risk of death in patients recovering
from a heart attack.
The Bottom Line:
Nitric oxide (NO) supplements don't actually contain nitric
oxide (a gas) but include the ingredient L-arginine which may increase nitric
oxide production in the body. L-arginine may improve circulation and, possibly,
some aspects of exercise performance -- but probably not for well-trained
athletes. Despite their popularity in bodybuilding circles, there's also no
clear evidence that NO products lead to gains in strength, muscle size, or
muscle "pump". If you want to try L-arginine, it would be wise to
choose a product that lists the actual amount of L-arginine on the label, as
opposed to a proprietary blend that doesn't. A daily dose of about 6 grams per
day has shown benefit for specific uses noted above. You can look at ConsumerLab.com's
Review of L-Arginine Supplements for quality ratings and
price comparisons of several L-arginine supplements. Be sure to review
the Concerns and Cautions with L-arginine in
that report, which includes a warning against L-arginine supplements if you
have had a heart attack and potential effects on the stomach and insulin
response.
Information on this site
is provided for informational purposes only. It is not an endorsement of any
product nor is it meant to substitute for the advice provided by physicians or
other healthcare professionals. The information contained herein should not be
used for diagnosing or treating a health problem or disease. Consumers should
inform their healthcare providers of the dietary supplements they take.
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